Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “VASOPRESSIN”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 667 records · Page 37Linked to original sources
PubMed1996

Membrane-delimited G protein-mediated coupling between V1a vasopressin receptor and dihydropyridine binding sites in rat glomerulosa cells.

In rat glomerulosa cells, vasopressin stimulates intracellular calcium mobilization via at least two distinct mechanisms: the release of calcium from inositol-1,4,5-P3-sensitive stores and the activation of transmembrane calcium influx. In this study, we focused on the second mechanism through three experimental approaches. By videomicroscopically examining Fura-2-loaded cells, we demonstrate that vasopressin induces a dose-dependent and receptor-mediated calcium influx fully inhibited by either 1 microM nifedipine or a pertussis toxin pretreatment and potentiated by 1 microM BAY K 8644. Patch-clamp experiments also indicate that vasopressin stimulates L-type calcium current by 87% and only weakly inhibits T-type calcium current. To further characterize the coupling between the vasopressin receptor and the dihydropyridine calcium channel, we performed binding studies using tritiated nitrendipine. With this technique, we showed that on intact cells, vasopressin is able to increase the specific binding of tritiated nitrendipine in a dose-dependent manner (Kact = 2 nM). Pharmacological studies using a series of vasopressin analogs revealed that this effect is mediated via a V1a vasopressin receptor subtype. Furthermore, the vasopressin-stimulated nitrendipine binding was sensitive to pertussis toxin pretreatment, which affected only the maximum binding capacity of nitrendipine-binding sites. More interestingly, we demonstrate that vasopressin still increases nitrendipine binding to plasma membrane preparation and that GTP is absolutely necessary for such a hormonal effect. Altogether, these data confirm the existence of a tight and direct coupling between the V1a vasopressin receptor and a dihydropyridine calcium channel via a pertussis toxin-sensitive G protein.

Animals↗
PubMed1998

Expression of all known vasopressin receptor subtypes by small cell tumors implies a multifaceted role for this neuropeptide.

Vasopressin is one of several small neuropeptides that are reported to be autocrine growth factors for small cell carcinoma of the lung (SCCL). It has been assumed that this peptide exercises its mitogenic influences through the vasopressin V1a receptor, and we have previously demonstrated that this receptor is expressed by classical and variant SCCL. Activation of the vasopressin V1a receptor produces changes in phospholipases C, D, and A2, in protein kinase C, and in Ca2+ mobilization. This study demonstrates that SCCL cells express not only vasopressin V1a receptors but also mRNAs and proteins representing normal V1b receptors and V2 receptors. They were also shown to express mRNA for a human form of the putative receptor rabbit vasopressin-activated calcium-mobilizing receptor (VACM-1). Additionally, SCCL tumor cells were found to express mRNA and protein representing a possible nonfunctional, shortened, "diabetic" form of the vasopressin V2 receptor that is the product of incomplete posttranscriptional splicing. At least four of these five vasopressin receptors were produced by cell lines exemplifying classical and variant forms of SCCL. No differences in the sequences for the V1 receptors between classical and variant SCCL were found. However, although the nature and expression of both vasopressin V1 receptors and human VACM are apparently unaffected by dedifferentiation in SCCL, only the abnormal (and probably nonfunctional) form of the V2 receptor could be demonstrated in variant cell line NCI H82. Functional engagement of vasopressin V2 receptors is reported to produce rises in cAMP and activation of protein kinase A, whereas stimulation of V1b receptors is believed to produce similar changes to those produced by V1a receptors, i.e., activation of phospholipases and of protein kinase C. Stimulation of VACM receptors raises intracellular free Ca2+ through currently unknown but phosphoinositide-independent mechanisms. The presence of all known vasopressin receptors that are, together, potentially capable of inducing several different transduction cascades in small cell tumor cells suggests that this peptide serves a multifaceted role in tumor physiology.

Animals↗
PubMed1998

Role of vasopressin on adrenergic neurotransmission in human penile blood vessels.

We have used in vitro preparations of human penile dorsal artery and deep dorsal vein from 20 multiorgan donors to investigate whether subpressor concentrations of vasopressin facilitate noradrenergic transmission in penile blood vessels. Vasopressin constricted penile dorsal arteries (pD2, 9.38 +/- 0.18) and deep dorsal veins (pD2, 9. 40 +/- 0.14) by activating V1 receptors. Vasopressin (10(-11) and 3 x 10(-11) M) caused concentration-dependent potentiation of the contractions elicited by electrical stimulation (15 V, 0.5-2 Hz, 0.2 msec duration for 15 sec) and produced leftward shifts of the concentration-response curve for norepinephrine. The V1 receptor antagonist d(CH2)5Tyr(Me)AVP (3 x 10(-9)-10(-7) M) induced concentration-dependent inhibitions of potentiation caused by vasopressin. In contrast, the V2 receptor antagonist [d(CH2)5,D-Ile2, Ile4,Arg8]-vasopressin (10(-8)-10(-7) M) did not prevent the potentiation induced by vasopressin. The results demonstrate that vasopressin exerts powerful constrictor action in human penile arteries and veins by direct stimulation of V1 receptors. In addition, vasopressin strongly potentiates the contractions to norepinephrine and stimulation of perivascular adrenergic nerves. Consequently, the direct contractile effects of vasopressin together with its amplifying effects on adrenergic-mediated constriction should be taken into consideration in the overall regulation of penile erection and in those states characterized by increased plasma vasopressin levels.

Adolescent↗
PubMed1997

Endothelium-dependent relaxation of human saphenous veins in response to vasopressin and desmopressin.

PURPOSE: The goal of this study was to determine the effects of vasopressin and the selective V2-receptor agonist desmopressin on human saphenous veins, with special emphasis on endothelium-mediated responses. METHODS: Human saphenous vein segments were obtained from 35 patients undergoing coronary bypass surgery. Paired segments, one normal and the other deendothelized by gentle rubbing, were mounted for isometric recording of tension in organ baths. Concentration-response curves to vasopressin and desmopressin were determined in the presence and in the absence of either the V1-receptor antagonist d(CH2)5Tyr (Me)AVP (10(-6) mol/L), the V1-V2-receptor antagonist desGly-d(CH2)5D-Tyr(Et)ValAVP (10(-6) mol/L), indomethacin (10(-6) mol/L), or NG-nitro-L-arginine methyl ester hydrochloride (L-NAME, 10(-4) mol/L). RESULTS: In vein rings under resting tension, vasopressin produced concentration-dependent, endothelium-independent contractions with a concentration of vasopressin producing half-maximal contractions (EC50) of 3.44 x 10(-8) mol/L. The vasopressin V1-receptor antagonist (10(-6) mol/L) displaced the control curve to vasopressin 9.86-fold to the right in a parallel manner. In precontracted vein rings previously treated with the V1-antagonist (10(-6) mol/L) vasopressin caused endothelium-dependent relaxations. This relaxation was reduced significantly by indomethacin (10(-6) mol/L) and unaffected by the V1-V2-receptor antagonist (10(-6) mol/L) or by L-NAME (10(-4) mol/L). Desmopressin caused endothelium-dependent relaxations in precontracted vein rings that were inhibited by the mixed V1-V2-receptor antagonist and by indomethacin, but not by the V1-antagonist or by pretreatment with L-NAME. CONCLUSIONS: These observations indicate that vasopressin exerts contractile effects on human saphenous vein by V1-receptor stimulation. Vasopressin causes dilatation of human saphenous vein only if V1-receptor blockade is present. This relaxation appears to be mediated by the release of relaxant prostaglandins, probably derived from endothelial cells, and is independent of V2-receptor stimulation or release of nitric oxide. Desmopressin elicits relaxation that is largely dependent on V2-receptor stimulation, which may bring about the release of dilating prostaglandins from the endothelial cells.

Adult↗
PubMed1993

Role of V1 receptors in the action of vasopressin on the baroreflex control of heart rate.

Arginine vasopressin (AVP) elicits a larger decrease in heart rate for a given increase in arterial pressure than do other vasoconstrictors, but there is disagreement as to whether this results from an increase in baroreflex gain or a resetting of the baroreflex to a lower blood pressure. It is also unclear which type of vasopressin receptor mediates the action of vasopressin on the baroreflex. In the present study, the effects of vasopressin, selective vasopressin V1 and V2 receptor agonists, oxytocin, and a vasopressin V1 receptor antagonist on the baroreflex control of heart rate were investigated in conscious, chronically prepared rabbits. Baroreflex curves were generated with intravenous infusions of phenylephrine and nitroprusside and analyzed using a four-parameter logistic model. Intravenous infusion of vasopressin at 5 ng.kg-1.min-1 increased mean arterial pressure by 9 mmHg and decreased heart rate by 31 beats/min. The arterial pressure at the midrange of the baroreflex curve (BP50) decreased from 75.9 +/- 4.8 to 57.6 +/- 1.7 mmHg (P < 0.01), indicating a shift of the baroreflex curve to a lower pressure, but the gain did not change significantly. The actions of vasopressin on blood pressure, heart rate, and BP50 were completely blocked by pretreatment with d(CH2)5[Tyr(Me)2]AVP, a selective V1 receptor antagonist. Infusion of [Phe2,Ile3,Orn8]AVP, a selective V1 receptor agonist, produced cardiovascular effects similar to those of vasopressin and decreased the BP50 of the baroreflex from 73.0 +/- 2.2 to 63.8 +/- 2.2 mmHg (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Vasopressin and oxytocin gene expression in the human hypothalamus.

We studied the distribution of messenger ribonucleic acids coding for vasopressin and oxytocin in the human hypothalamus by means of hybridization histochemistry. Numerous large and medium-sized neurons contain vasopressin messenger ribonucleic acid in the paraventricular nucleus, supraoptic nucleus, and accessory magnocellular nucleus. Small, lightly labeled vasopressin neurons also were detected in the suprachiasmatic nucleus. In addition, a relatively sparse band of mostly ovoid, medium-sized vasopressin neurons mingle with unlabeled neurons of the lateral hypothalamic area; these cells extend dorsoventrally from the region ventral to the stria terminalis to the ventrolateral hypothalamus, sometimes transgressing the boundaries of nearby nuclei. We did not detect vasopressin gene expression in neurons of the bed nucleus of the stria terminalis proper, although some of the dorsal-most labeled neurons of the lateral hypothalamus extend into the region of the caudal bed nucleus. Some lateral hypothalamic neurons also encroach upon other extrahypothalamic structures, such as the zona incerta. The nucleus basalis of Meynert complex was, with only rare exceptions, devoid of cells containing vasopressin messenger ribonucleic acid. Oxytocin messenger ribonucleic acid is found in the supraoptic nucleus, paraventricular nucleus, accessory magnocellular nucleus and, less frequently, in neurons of the lateral hypothalamus. In the hypothalamic magnocellular nuclei, oxytocin neurons are somewhat smaller than vasopressin neurons. Vasopressin cells outnumber oxytocin cells in the supraoptic nucleus, but their numbers are comparable in the paraventricular nucleus. As with vasopressin neurons, lateral hypothalamic oxytocin cells loosely span several diencephalic nuclei and encroach occasionally upon adjacent regions. These results confirm that the organization of vasopressin and oxytocin neurons in the human hypothalamus is largely comparable to that in nonhuman species and demonstrate the utility of hybridization histochemistry for elucidating the chemoarchitecture of the human brain.

Adolescent↗
PubMed1993

Vasopressin induces arachidonic acid release through pertussis toxin-sensitive GTP-binding protein in aortic smooth muscle cells: independence from phosphoinositide hydrolysis.

We previously reported that pertussis toxin (PTX) had little effect on arginine vasopressin-induced formation of inositol trisphosphate (IP3) in rat aortic smooth muscle cells [Kondo et al.: Biochemical and Biophysical Research Communications 161:677-682, 1989]. In the present study, we investigated the mechanism of vasopressin-induced arachidonic acid release in rat aortic smooth muscle cells. Vasopressin stimulated both the release of arachidonic acid and the formation of IP3 dose dependently in the range between 10 pM and 1 microM. The effect of vasopressin on arachidonic acid release was more potent than that on the formation of IP3. Quinacrine, a phospholipase A2 inhibitor, significantly suppressed the vasopressin-induced arachidonic acid release but had little effect on the formation of inositol phosphates. NaF, a GTP-binding protein activator, mimicked vasopressin by stimulating the arachidonic acid release. The arachidonic acid release stimulated by a combination of vasopressin and NaF was not additive. PTX partially but significantly suppressed the vasopressin-induced arachidonic acid release. In the cell membranes, PTX catalyzed ADP-ribosylation of a protein with an M(r) of about 40,000. Pretreatment of membranes with 0.1 microM vasopressin in the presence of 2.5 mM MgCl2 and 100 microM GTP markedly attenuated this PTX-catalyzed ADP-ribosylation of the protein in a time-dependent manner. These results strongly suggest that PTX-sensitive GTP-binding protein is involved in the coupling of vasopressin receptor to phospholipase A2 in primary cultured rat aortic smooth muscle cells.

Adenosine Diphosphate Ribose↗
PubMed1984

Homologous and heterologous mitogenic desensitization of Swiss 3T3 cells to phorbol esters and vasopressin: role of receptor and postreceptor steps.

Prolonged treatment of Swiss 3T3 cells with phorbol 12,13 dibutyrate (PDB) rendered the cells refractory to subsequent mitogenic stimulation by both PDB and vasopressin. In contrast, the cells retained full responsiveness to a wide variety of other mitogens. An early response to vasopressin and phorbol esters, inhibition of (125I)-labeled epidermal growth factor [(125I)-EGF] binding, was also substantially decreased in PDB pretreated cells. The cross desensitization was not produced by vasopressin; this ligand induced homologous but not heterologous desensitization. Exposure of Swiss 3T3 cells to PDB caused a down regulation of (3H)-PDB receptors but did not reduce the binding of vasopressin to refractory cells. The time-course (t1/2 = 7 h) and dependence on PDB concentration (half maximal at 20 nM) for this phorbol ester receptor loss paralleled the induction of the mitogenic desensitizations to both PDB and vasopressin. However, the time-course of recovery revealed an important dissociation between receptor presence and mitogenic response. When Swiss 3T3 cultures, which had been pretreated with PDB, were washed to remove this ligand and incubated in its absence for 24 h, both (3H)-PDB receptors and PDB or vasopressin inhibition of (125I)-EGF binding were almost completely restored to control levels. However the homologous and heterologous mitogenic desensitizations showed a very different reversal time. After a 24-h recovery period PDB-treated refractory cells were still unable to synthesize DNA in response to PDB or vasopressin. The mitogenic desensitizations were however completely reversible; after a 48-h incubation in the absence of PDB the cells responded fully to the mitogenic actions of PDB or vasopressin. This finding suggests that a further postreceptor step was also desensitized by prolonged PDB treatment. The presence of a low level of cycloheximide during the PDB pretreatment blocked induction of this postreceptor refractoriness. We propose that this refractory postreceptor step selectively blocks both PDB and vasopressin stimulation of DNA synthesis and may represent the point at which the mitogenic pathways of phorbol esters and vasopressin converge.

Animals↗
PubMed1986

Effect of salt loading and salt deprivation on the vasopressin and oxytocin content of the median eminence and the neural lobe in adrenalectomized rats.

In adrenalectomized rats the influence of salt loading or salt deprivation on the vasopressin and oxytocin content of the median eminence (ME) and the neural lobe (NL) was studied by means of various methods: morphometric and microphotometric analysis of aldehyde fuchsin-stained sections of ME and NL; immunohistochemical demonstration of neurophysin, oxytocin, and vasopressin in the ME and in the NL; radioimmunological measurement of oxytocin and vasopressin in the ME and in the NL. Adrenalectomy in salt-substituted rats raised the vasopressin content of the outer layer of the ME (OLME) but had no influence on the amount of vasopressin in the inner layer of the ME and in the NL. Osmotic stimulation of adrenalectomized rats by hypertonic saline markedly diminished vasopressin and oxytocin in the inner layer of the ME and in the NL but did not, or only slightly reduced vasopressin in the OLME. Withdrawal of salt supplementation in adrenalectomized rats resulted in a decrease of plasma sodium and plasma volume. It did not change the vasopressin or oxytocin content of the inner layer of the ME and of the NL, but it was correlated with a decrease of vasopressin in the OLME. The present findings may suggest that vasopressin in the OLME is involved in salt and/or volume regulation by influencing the hypophysial-adrenal axis.

Adrenalectomy↗
PubMed1975

Immunofluorescence of vasopressin and oxytocin in the rat hypothalamo-neurohypophypopseal system.

The present paper deals with the development of an immunofluorescence procedure that allows specific localization of vasopressin and oxytocin in the hypothalamo-neurohypophyseal system(hnx) of the rat. Antibodies against arginine vasopressin (AVP), lysine-vasopressin (LVP) and oxytocin were raised by injecting these hormones that were covalently bound to thyroglobulin into rabbits. The vasopressin-immunized rabbits showed periods of diabetes insipidus, while histoloty of the "hns revealed an intact neurosecretory system with signs of increased endogenous hormone synthesis in the supraoptic nucleus and increased release in the neuro-hypophysis of some rabbits. The daily water intake of the oxytocin-immunized rabbits was similar to that of control rabbits. The development of antibodies against vasopressin as measured in the immunofluorescence procedure showed a course that was quite different from the curve of the titer as determined by radioimmunoassay (RIA). Also the specificity of the antibodies used in the immunofluorescence procedure was found to be quite different from their specificity in a RIA system. Potency and specificity of the antibodies have to be studied therefore within the immunofluorescence procedure itself. Using freshly frozen acetone-postfixed hypotalami or pituitaries, no sharp localization of immunofluorescence could be obtained in the HNS. Therefore prefixation was performed. Both, the type and the duration of prefixation revealed quite different results regarding the immunofluorescence in the neurosecretory cell boides in the hypotalamus and of their endings in the neurohypophysis. The best immunofluorescence results were obtained using 6 hours glyoxal-prefixation for the hypothalamus and 24 hours formalin-prefixation for the pituitary. The cross-reaction of the antibodies for oxytocin or vasopressin was tested on synthetic hormones that were bound to CNBR-activated agarose beads and mounted on glass sides. All anti-plasmas showed cross-reaction on beads containing the heterologou- antigen. The plasmas were purified by incubation with beads containing the heterologous hormone until the cross-reacting component had been removed. Using purified antibodies, the distribution of oxytocin and vasopressin cells within the HNS was investigated. More oxytocin containing cells were localized in the rostral part and more vasopressin in the caudal part of both, the supraoptic (SON) and paraventricular nucleus (PVN). Comparable percentages of oxytocin and vasopressin containing cells were found in the SON and PVN. The absolute amount of oxytocin containing cells was 2.5 times more in the SON than in the PVN, which seems to contradict the "classical" view that the PVN predominantly or entirely synthetizes oxytocin. In addition, fluorescence was found using antobodies against vasopressin in the suprachiasmatic nucleus in Wistar rats and heterozygous Brattleboro rats, but not in this nucleus of homozygous Brattleboros.

Animals↗
PubMed1993

Effects of central vasopressin administration to infant rats.

The neurohypophyseal peptide hormone arginine-vasopressin functions as a neuropeptide in several brain areas in addition to its role as a posterior pituitary hormone. Several studies indicate that arginine-vasopressin and arginine-vasopressin receptors appear early in the infant rat brain. To determine if arginine-vasopressin receptors in the infant were responsive to exogenous peptides, we compared the behavioral effects of central or peripheral administration of arginine-vasopressin, arginine vasotocin, the oxytocin precursor oxytocin-Gly-Lys-Arg, and arginine-vasopressin receptor antagonists in socially isolated rat pups. Central administration of arginine-vasopressin decreased the number of rat pup ultrasonic vocalizations, reduced locomotor activity and decreased the latency to express a response to negative geotaxis. Temperature was also reduced at all doses tested. Co-administration of arginine-vasopressin and receptor antagonists suggested that changes in vocal behavior were mediated by the V1 receptor subtype. Changes in core temperature appeared to be mediated by a V2 receptor subtype. Peripheral arginine-vasopressin administration increased calling and decreased core body temperature. Neither effect was blocked by central receptor antagonist administration. The results are consistent with the hypothesis that arginine-vasopressin receptors in the infant rat brain are functional.

Animals↗
PubMed1986

Vasopressin gene expression is attenuated in the fetal Brattleboro rat.

Due to a genetic defect the homozygous Brattleboro rat is unable to synthesize vasopressin gene products but still transcribes a mutant vasopressin mRNA from the gene. To study the influence of vasopressin gene products on the development of vasopressin gene expression, vasopressin mRNA levels of the supraoptic and paraventricular nucleus were measured at fetal day 20, postnatal day 1, 15 and 30 in the Wistar rat and in the heterozygous and homozygous Brattleboro rat by Northern blot analysis and in situ hybridization. In the homozygous Brattleboro rat of fetal day 20 and postnatal day 1, no or minute amounts of vasopressin mRNA were detectable but vasopressin mRNA was readily detectable at postnatal day 15 and 30. The Wistar rat and heterozygous Brattleboro rat had abundant vasopressin mRNA at fetal day 20 with increasing amounts towards postnatal day 30. The results indicate that vasopressin gene expression in the development of the homozygous Brattleboro rat is attenuated, possibly due to the absence of vasopressin gene products.

Animals↗
PubMed1984

Vasopressin: a potent growth factor in adrenal glomerulosa cells in culture.

Previous studies have shown that vasopressin stimulates the mitotic activity in adrenal zona glomerulosa cells in intact as well as in hypophysectomized rats. (Payet and Isler, Cell and Tissue Res. 172, 1976; Payet and Lehoux, J. steroid Biochem. 12, 1980). We now report that this effect is direct and specific, since vasopressin stimulates the mitotic activity of rat adrenal zona glomerulosa cells in primary cultures. These cells were prepared by dissociation with collagenase in the culture medium MEM-d-Valine. Isolated cells were placed in 3.5 diameter petri dishes in MEM-d-valine medium containing 15% fetal calf serum and antibiotics for two days and 5% fetal calf serum for subsequent cultures. The medium was changed at 24 hr intervals. The hormones were added 3 days after the culture was started. The mitogenic effect of vasopressin was found to be dependent both on time and hormone concentrations. Vasopressin (10(-11) M) stimulated thymidine incorporation 4.8 +/- 0.6-fold after 2 days of treatment and 5.3 +/- 1.6-fold after 8 days. When ACTH (10(-11) M) was added together with vasopressin (10(-11) M) the mitogenic effect was enhanced at 6.5 +/- 1.9-fold after 2 days and 12.9 +/- 6.9-fold after 8 days of treatment. The aldosterone and corticosterone outputs were also stimulated by the combined presence of vasopressin and ACTH in the incubation medium; a maximal effect was observed between 6 and 8 days of treatment. Vasopressin (10(-11) M) + ACTH (10(-11) M) stimulated the aldosterone output 7-fold and that of corticosterone by 18-fold. When added alone, vasopressin, as well as ACTH alone had only a small effect on the aldosterone output. However, ACTH alone stimulated the corticosterone output 10-fold. In conclusion, vasopressin is an important and specific growth factor of the adrenal zona glomerulosa cells. In addition, together with ACTH vasopressin stimulates the aldosterone and corticosterone output both in vivo and in vitro in primary cell cultures.

Adrenal Cortex↗
PubMed1982

Blood pressure and heart rate responses to microinjection of vasopressin into the nucleus tractus solitarius region of the rat.

The nucleus tractus solitarius (NTS) region in the rat has been shown to receive arginine vasopressin (AVP) and oxytocin (OT) neurophysin-containing neuronal projections from the suprachiasmatic (SNC) and paraventricular nucleus (PVN). Thus, vasopressin and oxytocin might have central influences on the circulation. This as investigated by measuring arterial blood pressure and heart rate (HR) responses following microinjection of vasopressin and oxytocin (0.1, 1.0 and 10.0 ng) into the right nucleus tractus solitarius region of rats anesthetized with urethane. Injections of vasopressin into nucleus tractus solitarius produced dose-related increases in blood pressure and heart rate. The effect of oxytocin on the blood pressure and heart rate was of a lesser magnitude without showing a dose-response relationship. Equivolumetric injections of vehicle and luteinizing hormone-releasing hormone (LH-RH) peptide had no detectable effect on blood pressure and minimal effect on heart rate. Injections of vasopressin into three different sites in the brain stem (1 mm anterior, posterior, and lateral to the tractus solitarius) did not produce significant hemodynamic changes. Intravenously injected vasopressin produced increments in blood pressure only at the highest dose level (10.0 ng) and a decrease rather than an increase in heart rate. Ganglionic blockade significantly reduced pressor responses to vasopressin injected into the nucleus tractus solitarius region and completely eliminated HR responses. Pretreatment of the nucleus tractus solitarius with a vasopressin antagonist abolished the blood pressure and heart rate responses produced by injection of vasopressin. These results suggest that vasopressin acts in the region of the nucleus tractus solitarius to exert a central action on the circulation.

Animals↗
PubMed1977

Vasopressin administration in the first month of life: effects of growth and water metabolism in hypothalamic diabetes insipidus rats.

Rats homozygous for the mutant gene for diabetes insipidus (Brattleboro strain) are stunted in growth compared to rats heterozygous for the mutant gene and normal rats without the mutant gene. The hypothesis was tested that normal growth depends upon the presence of vasopressin. It was expected that replacement therapy of vasopressin rats homozygous for diabetes insipidus would make possible a normal growth rate similar to that of rats heterozygous for diabetes insipidus. Rats heterozygous and homozygous for diabetes insipidus were treated with 0.25 U (Days 0-9) and 0.5 U (Days 10-29) of vasopressin during the first month of life. During the treatment period, vasopressin significantly increased the urine osmolatities of the homozygous rats demonstrating the renal effectiveness of the vasopressin. The results showed that remedial vasopressin administration could not produce normal growth rates in homozygous rats and may be detrimental. Six weeks following vasopressin treatment, homozygous, diabetes insipidus rats which had received vasopressin had increased 24 hr water intakes and decreased urine osmolalities compared to control, homozygous rats, Heterozygous rats also had decreased urine osmolalities resulting from vasopressin six weeks after the cessation of vasopressin treatment.

Aging↗
PubMed1992

Hemodynamic effects of a combination of vasopressin and ketanserin in patients with hepatitis b-related cirrhosis.

We measured the hemodynamic effects of intravenous vasopressin, ketanserin (a 5-hydroxytryptamine-2 receptor blocker), and vasopressin plus ketanserin in 33 patients with hepatitis B-related cirrhosis. Thirteen patients received vasopressin alone (0.66 units/min), ten patients ketanserin alone (10 mg), and ten patients vasopressin followed by vasopressin plus ketanserin. Vasopressin alone reduced the hepatic venous pressure gradient (from 18 +/- 5, mean +/- S.D., to 9 +/- 3 mmHg, p less than 0.0001) and cardiac output (p less than 0.0001), but increased mean arterial pressure (p less than 0.005), mean pulmonary arterial pressure (p less than 0.0001), pulmonary capillary wedge pressure (p less than 0.0001), and systemic vascular resistance (p less than 0.001). There was no significant change in heart rate. Ketanserin alone produced a significant fall in the hepatic venous pressure gradient (from 16 +/- 4 to 13 +/- 3 mmHg, p less than 0.0001), mean arterial pressure (p less than 0.005), mean pulmonary arterial pressure (p less than 0.005), and pulmonary capillary wedge pressure (p less than 0.005). Heart rate, cardiac output, and systemic vascular resistance were not significantly changed. The addition of ketanserin to vasopressin corrected most of the systemic hemodynamic disturbances produced by vasopressin. This combination did not lead to a further reduction in the hepatic venous pressure gradient. We conclude that intravenous ketanserin reduces portal pressure in patients with hepatitis B-related cirrhosis. The addition of ketanserin to vasopressin improves the detrimental systemic hemodynamic effects of vasopressin without further reducing the portal pressure.

Aged↗
PubMed1985

Vasopressin and brain development: studies using the Brattleboro rat.

Anomalies in hormonal and neurotransmitter status during early stages of brain development, can lead to lifespan alterations in the functioning of central systems. The neuropeptide vasopressin is nowadays recognized as a putative neurotransmitter, after years of study on its neurosecretory hormonal aspect in water metabolism. Since vasopressin is moreover present early in the brain, and has various mitogenic, metabolic and physiological actions, one might expect vasopressin to be of importance for normal brain development as well. Indeed, the absence of brain vasopressin in the Brattleboro mutant rat coincides with impaired brain development, and some physiological and behavioral defects of these rats are not adjusted by treatment with vasopressin. Regionally the cerebellum seems to be the most affected brain area, both morphologically and biochemically. Only when vasopressin supplementation was done prenatally, this disturbed growth could be restored, which suggests an early role for vasopressin in neurogenesis. Enhanced levels of vasopressin during the perinatal period on the other hand, have been shown to affect permanently the 'setting' of peripheral vasopressin functions in cardiovascular and renal regulatory systems. It is not excluded as yet that after such treatments central organization of vasopressin systems is not impaired as well.

Aging↗
PubMed1995

Structure--function studies of vasopressin analogues with D-3 pyridyl-alanine in position 2.

A number of analogues of vasopressin, incorporating the substitution of D-3'-(pyridyl)-alanine in position 2, were synthesized and tested for antidiuretic (V2), vasoconstrictor (V1a) and ACTH secretory (V1b; pituitary) activities. One analogue, deamino-[D-3'-(pyridyl)-alanine2]arginine-vasopressin (abbreviated d[D-3Pal]VP) was a potent pituitary agonist, weaker antidiuretic agonist, and weak vasoconstrictor antagonist. Another analogue, [D-3'-(pyridyl)-alanine2]arginine-vasopressin, had very weak pituitary activity but no measurable antidiuretic or vasoconstrictor activity. Other D-3'-(pyridyl)-alanine-substituted analogues had only very weak activity in one or two of the bioassays. In further examination of the relationship between the actions of vasopressin on generation of cyclic AMP and secretion of ACTH in pituitary cells, the cyclic AMP responses to d[D-3Pal]VP, to another analogue of vasopressin ([Val4,D-Arg8]VP) with potent agonist activity at pituitary and renal (V2) receptors, and to CRF were compared to that of vasopressin. At the prescribed concentrations, the ACTH secretory responses to vasopressin, d[D-3Pal]VP, and [Val4,D-Arg8]VP were comparable; but only ([Val4,D-Arg8]VP) and CRF, which did not change ACTH secretion, increased intracellular cyclic AMP. These results indicate the possibility of synthesizing analogues of vasopressin with selective activity for the pituitary response and the potential for further study of vasopressin receptor subtypes, using the D-3'-(pyridyl)-alanine substitution. They are also consistent with the concept that the ACTH secretory response to vasopressin by itself is not linked to cyclic AMP, although adenylate cyclase may be activated.

Adenylyl Cyclases↗