Biomedical subjects
A Hidalgo
Publications and source records attributed to A Hidalgo.
Mechanisms involved in the spasmolytic effect of extracts from Sabal serrulata fruit on smooth muscle.
1. The effects of two extracts from Sabal serrulata fruits [total lipidic (L) and saponifiable (S)] on smooth muscle contractions have been assayed. 2. Both extracts (0.1-1 mg/ml) relaxed the tonic contraction induced by norepinefrine (30 nM) on rat aorta [EC50, 0.53 +/- 0.05 mg/ml (L) and 0.5 +/- 0.04 mg/ml (S)] and by KCl (60 mM) on rat uterus. The Sabal extracts (0.3-1 mg/ml) also antagonized the dose-response curve of contractions induced by acetylcholine (0.1-100 microM) on urinary bladder. 3. dL-Propranolol (1 microM) but not the inactive (R)-(+)-propranolol(1 microM) potentiated the Sabal extracts relaxant effect by lowering the EC50 (0.35 +/- 0.2 vs 0.20 +/- 0.01 mg/ml for L and 0.43 +/- 0.02 vs 0.19 +/- 0.02 mg/ml, P < 0.01, for S extract). 4. Cycloheximide (10 micrograms/ml) antagonized the effect of extracts from Sabal. However, actinomycin D (5 micrograms/ml) significantly (P < or = 0.01) antagonized the effect of the total lipidic extract without modifying that of the saponifiable extract. 5. The relaxant effect of both extracts was not modified by the tyrosine kinase inhibitor genistein (10 microM) or the ornithine decarboxylase inhibitor alpha-difluoromethyl-ornithine (10 mM).
Calcium and depolarization-dependent effect of pregnenolone derivatives on uterine smooth muscle.
1. The effects of several gestagens (pregnenolone [1 to 30 microM], 20 alpha-hydroxy-pregnenolone [1 to 30 microM], and 20 beta-hydroxypregnenolone [1 to 30 micro M]) on rat uterine contraction induced by KCl (60 mM) and CaCl2 (30 microM to 6 mM) have been assayed. 2. The three drugs relaxed the tonic contraction induced by KCl in a concentration-dependent way. The respective EC50 values were: 27.6 +/- 1.58 microM (pregnenolone), 4.1 +/- 0.12 microM (20 alpha-hydroxy-pregnenolone), and 11.2 +/- 1.04 microM (20 beta-hydroxypregnenolone). CaCl2 (1 to 10 mM) totally counteracted the relaxing effect of pregnenolone but only partially compared to that of 20 alpha- or 20 beta-hydroxy-pregnenolone. 3. CaCl2 (30 microM to 6 mM) produced concentration-dependent contraction of rat uterus in medium lacking calcium plus 30, 60, or 90 mM of KCl. The EC50 values of CaCl2 were: 0.38 +/- 0.072, 0.183 +/- 0.015, and 0.183 +/- 0.015 mM in a medium with 30, 60, or 90 mM of KCl, respectively. 4. Pregnenolone (10 microM) did not significantly modify the EC50 of CaCl2 in a medium with 30, 60, or 90 mM of KCl. However, 20 beta-hydroxypregnenolone (10 microM) antagonized, in a noncompetitive manner, the concentration-response curve to CaCl2. 5. 20 alpha-Hydroxypregnenolone (4 microM) antagonized the concentration-response curve to CaCl2 in a competitive manner. This antagonism was directly related to the concentration of KCl in the medium. 6. Our results suggest a different calcium antagonist effect of the three gestagens assayed.
Characterization of TGF-beta 1-binding proteins in human bone marrow stromal cells.
The proliferation and differentiation of haemopoietic progenitor cells is dependent on their close relation with bone marrow stromal cells, which constitute a source of cytokines as well as expressing receptors for both the cytokines and progenitor cell adhesion molecules necessary for regulated haemopoiesis. We have generated human bone marrow stromal cell cultures and analysed the TGF-beta 1 receptor components expressed by these cells. [125I]TGF-beta 1-affinity labelling experiments showed the involvement of type I and II receptors in the binding of TGF-beta 1, as demonstrated by specific immunoprecipitation of [125I]TGF-beta 1-receptor complexes. In addition, large TGF-beta 1-labelled complexes displaying an electrophoretic mobility similar to betaglycan were also observed in these experiments. Endoglin, another component of the TGF-beta receptor system, was detected by flow cytometry on the surface of cultured marrow stromal cells, and in the human bone marrow stromal cell line Str-5, and was immunoprecipitated from surface-iodinated cells. Endoglin on the stromal cells was able to bind TGF-beta 1, as demonstrated by specific immunoprecipitation of [125I]TGF-beta 1-endoglin complexes using anti-endoglin antibodies. The results presented provide evidence that bone marrow stromal cells are fully capable of responding to TGF-beta 1. Given the important role of TGF-beta as a regulator of the synthesis of cytokines and cytokine receptors, as well as cell adhesion molecules, these data indicate that the binding of TGF-beta 1 by stromal cells might represent an important step in the regulation of the proliferation and differentiation of haemopoietic progenitor cells.
Spasmolytic activity of a lipidic extract from Sabal serrulata fruits: further study of the mechanisms underlying this activity.
The mechanisms involved in the spasmolytic effect of a lipidic extract from Sabal serrulata fruits were investigated. The extract relaxed vanadate-induced contractions on rat uterus incubated in a calcium free solution (EC50 = 11.41 +/- 1.38 micrograms/ml). The modification of the effect by a cyclooxygenase inhibitor (indomethacin), a protein kinase A inhibitor (TPCK), calcium modifying drugs, and drugs interfering with transcription and protein synthesis has been assayed. The effect was unmodified by a 3 microM concentration of indomethacin, (EC50 = 8.77 +/- 1.28 vs 11.41 +/- 1.38 micrograms/ml) and a 5 micrograms/ml concentration of the transcription inhibitor, actinomycin D, (EC50 = 8.23 +/- 2.19 vs 11.41 +/- 1.38 micrograms/ml). The inhibitor of intracellular calcium mobilization TMB-8 (0.1 mM), the Na+/Ca+2 exchanger inhibitor amiloride (0.1 mM), the calcium chelator BAPTA-AM (50 microM), the PKA inhibitor TPCK (10 microM), and the protein synthesis inhibitor cycloheximide (10 micrograms/ml) significantly shifted to the right the dose-response curve of the extract (EC50 = 17.83 +/- 1.87 micrograms/ml, 18.61 +/- 2.50 micrograms/ml, 35.28 +/- 9.13 micrograms/ml, 33.99 +/- 3.07 micrograms/ml, and 27.31 +/- 4.93 micrograms/ml, respectively, vs 11.41 +/- 1.38 micrograms/ml). These results suggest that the effect of the lipidic extract from S. serrulata fruits could be partially due to Na+/Ca+2 exchanger activation and interference with intracellular calcium mobilization, and point to cAMP as a possible mediator. Moreover, protein synthesis seems to be involved in the spasmolytic activity.
Role of cyclic nucleotides in contraction induced by oxytocin in the testicular capsule of the rat in vitro.
The effects of phosphodiesterase inhibitors, an activator and an inhibitor of guanylyl cyclase, and cAMP and cGMP analogs on oxytocin-induced contractions have been studied in the testicular capsule of rats. The nonspecific phosphodiesterase inhibitors, theophylline and caffeine, attenuated the oxytocin-induced contractions via mechanisms that seem to be related to an increase in cAMP levels, since a similar effect was produced by dibutyryl cAMP. Sodium nitroprusside facilitated oxytocin-induced contractions. This effect was mimicked by dibutyryl cGMP. Methylene blue, an inhibitor of soluble guanylyl cyclase, decreased oxytocin-induced contractions, which suggests an involvement of guanylyl cyclase in the oxytocin effect. These results suggest that cAMP modulates the contraction and that cGMP, contrary to what happens in most smooth muscles, could participate in oxytocin-induced contractions in the testicular capsule of rats.
Pharmacological dissociation of UTP- and ATP-elicited contractions and relaxations in isolated rat aorta.
Effects of UTP have been described in many tissues, but it is not clear whether these are due to purinoceptors. Specific receptors for UTP, 'pyrimidinoceptors', and 'nucleotide receptors' have also been proposed. We pharmacologically characterized the receptors involved in the ATP- and UTP-induced contraction under basal tone and the relaxation of raised tone elicited by noradrenaline in isolated rat aorta. The rank order of potency for the agonists for the contraction was alpha,beta-methylene ATP > > ATP, and the desensitization by alpha,beta-methylene ATP suggests that ATP contractions were mediated via P2X purinoceptors which were located on the vascular smooth muscle. The rank order of potency of the agonists for relaxation was 2-methyl-thio ATP > > ATP, which is suggestive of a P2Y purinoceptor. However, the relaxation seems to be unrelated to the classical P2Y subtype and a heterogeneous population of purinoceptors might therefore exist. The evidence comes from the distinct location and the different pharmacological effect of reactive blue 2 on 2-methyl-thio ATP and ATP receptors. 2-Methyl-thio ATP produced an endothelium-dependent relaxation while ATP-induced relaxation was produced via endothelium-dependent and endothelium-independent mechanisms, unrelated to adenosine receptors. It is unlikely that UTP-induced contractions and the endothelium-dependent relaxation were produced via purinoceptors since the pharmacology is not consistent with that of the classical P2 purinoceptors studied. Furthermore, UTP-sensitive receptors showed a pharmacological property that was also distinct from that of the 'nucleotide' or P2U receptor reported. The results suggest the presence of a heterogeneous population of purinoceptors and pyrimidinoceptors pharmacologically different from the receptors for ATP.
Estrogens and non-estrogenic ovarian influences combine to promote the recruitment and decrease the turnover of new neurons in the adult female canary brain.
The higher vocal center (HVC) of the songbird forebrain exhibits persistent neurogenesis in adulthood, particularly in a region of the mediocaudal neostriatum that is associated with a subventricular layer of estrogen receptive cells. We asked whether estrogens might influence adult neurogenesis, by assessing the effect of ovariectomy on HVC neuronal production in the adult female canary. Fifteen 1-year-old females were separated into groups of ovariectomized, estradiol-replaced ovariectomized, and gonadally intact birds. To label dividing cells and their progeny, the birds were given [3H]thymidine for 8 days, killed 32 days later, and their brains autoradiographed. A significant rise was noted in the number of HVC neurons per section in estradiol-treated birds relative to the untreated control birds. The number of [3H]thymidine-labeled HVC neurons was also higher in the estrogen-treated birds; however, the neuronal labeling index (LI) did not vary as a function of estradiol replacement, as the total number of HVC neurons rose in parallel with the added new neurons. In contrast, the neuronal LI did rise as a result of ovariectomy, and this ovariectomy-associated increase in the LI was not reversed by estradiol. Among non-neuronal cell types, the endothelial LI was higher in estrogen-treated birds than in their untreated counterparts, suggesting estrogen-associated angiogenesis. Radioimmunoassay confirmed that serum estradiol was reduced in the castrated birds. Since estrogen appeared to promote the survival of [3H]thymidine+ neurons, we next sought to determine whether estrogen acted directly on the newly generated neurons, or rather indirectly through an intermediary cell population. To this end, we asked whether the new neurons or their precursors expressed estrogen receptor immunoreactivity (ER-IR). Five adult male canaries were given [3H]thymidine for periods ranging from 2 to 28 days, killed at varying times up to 3 weeks thereafter, then probed for ER-IR and autoradiographed. [3H]thymidine+ cells displayed no detectable ER-IR within their first 4 weeks of postmitotic life. Rather, during migration from the ventricular zone (VZ), the new neurons traversed a layer of mitotically quiescent, ER+ subventricular cells. Double labeling for ER-IR and cell-type selective antigens confirmed that these ER+ cells were neurons. These results indicate that the early survival of new neurons in the adult songbird HVC is promoted by estrogen, and may be mediated by the estrogen-stimulated paracrine release of neurotrophic agents by ER-IR subventricular neurons. Our data suggest that estrogen's promotion of neuronal survival may operate concurrently with an estrogen-independent ovarian suppression of neuronal mitogenesis.
Extracellular and intracellular effects of polyamines on smooth muscle contractions.
The natural polyamines spermine, spermidine and putrescine, and their metabolic products N1-acetylspermine (N-AS) and 5'-deoxi-5'-methyl-thioadenosine (DMT), but not N1-acetylspermidine nor N-acetylputrescine, relax the KCl-induced contraction in rat uterus in a dose-dependent way. This relaxing effect is counteracted by CaCl2 (0.1-6 mM) but not by Bay K 8644. Spermine, N-AS and DMT also inhibit the contraction induced by methacholine and PGF2 alpha. Spermine, DMT and N-AS relax the vanadate-induced contraction in uterus incubated in calcium-free solution plus EDTA. However, in the vanadate contraction, the EC50s are higher than those obtained with other contracturants. These results suggest that polyamines inhibit smooth muscle contraction by action at plasma membrane level decreasing the influx of calcium. However, intracellular actions of polyamines could also be involved in their effects.
Spasmolytic and calmodulin inhibitory effect of non-steroidal anti-inflammatory drugs in vitro.
The effect of several anti-inflammatory drugs (NSAIDs), the calmodulin inhibitor W-7 and cortisol on vanadate-induced tonic contraction and on calmodulin dependent cAMP-phosphodiesterase activity have been assayed. Indomethacin, diclofenac, phenylbutazone, mefenamic acid, naproxen, tolmetin, piroxicam, aspirin and W-7, but not metimazol, produce dose-dependent relaxation of vanadate-induced tonic contraction on isolated rat uterus. Cortisol relaxes the vanadate contraction up to 45%. None of the drugs assayed inhibit the basal activity of phosphodiesterase with concentrations lower than 1 mM. However, indomethacin, diclofenac, phenylbutazone, mefenamic acid, naproxen, piroxicam, aspirin and W-7 inhibit, in a concentration-dependent way, the calmodulin-stimulated activity of phosphodiesterase. The maximum inhibition achieved with tolmetin (1 mM) and cortisol (1 mM) was 38% and 24%, respectively. Metamizol has no effect on basal or/and stimulated phosphodiesterase. This, as far as we know, is the first description of relationship between NSAIDs and calmodulin-dependent processes and our results suggest that the inhibition of calmodulin with NSAIDs may be directly related to their pKa and liposolubility.
Effects of preanesthetic and anesthetic drugs on endothelium-dependent responses in the rat aorta.
1. Acetylcholine often fails to induce endothelium-dependent relaxation in human vessels in vitro. Due to the fact that most of these vessels come from surgery, we examined the influence of drugs used in anesthesia on endothelium-dependent responses in rat aorta. 2. Groups of male Wistar rats of the following treatments were utilized: P group, diazepam+promethazine+atropine; I group, pentothal+succinylcholine; IG group, halothane+nitrous oxide; M group, morphine+pancuronium; C group, untreated rats. Dose-response curves to noradrenaline and acetylcholine were determined in rat aorta in vitro, in the presence and absence of endothelium. 3. Acetylcholine induced more relaxation (P < 0.05) in the rat aorta of IG group compared with that of the C group. 4. In the rat aorta from P and IG groups, the contractions produced by several concentrations of noradrenaline were significantly smaller (P < 0.05) when the endothelium was removed. Similar effects occurred in aorta strips of animals previously treated with either atropine, promethazine, cimetidine or halothane. 5. Our results suggest that drugs currently used in anesthesia interfere with some endothelium-dependent effects on isolated rat aorta but according to these results they do not seem to be responsible for the lack of acetylcholine relaxation sometimes described in human vessels in vitro.
Non-genomic effects of catecholestrogens in the in vitro rat uterine contraction.
1. The effects of catecholestrogens 2-hydroxyestradiol (2-OH E2, 0.6-30 microM), 4-hydroxyestradiol (4-OH E2, 1-30 microM) and 2-methoxyestradiol (2-MeO E2, 0.6-30 microM) on rat uterine contraction induced by KCl (60 mM), have been assayed. 2. All drugs assayed relaxed the tonic-contraction induced by KCl in a concentration-dependent way. The EC50s were: 4.4 +/- 0.5, 4.2 +/- 0.3 and 8.5 +/- 0.7 microM for 2-MeO E2, 2-OH E2 and 4-OH E2, respectively. This relaxing effect was counteracted by CaCl2 (1-10 mM) but not by the calcium channel agonist Bay k 8644 (1 nM-1 microM). 3. The effect of 2-MeO E2 is not modified by propranolol (1 microM), cycloheximide (35 microM), actinomycin D (4 microM), alpha-difluoromethyl-ornithine (10 mM) or genistein (10 microM). Nor did cycloheximide (35 microM) or actinomycin D (4 microM) modify the relaxing effect of 2-OH E2 and 4-OH E2. Propranolol (1 microM) significantly increased the effect of 4-OH E2 but not the effect of 2-OH E2. 4. Our results suggest that the relaxing effect of catecholestrogens in the rat uterus is a non-genomic effect and could be related to inhibition of extracellular calcium entry.
Influence of hormonal status in relaxant effect of diethylstilbestrol and nifedipine on isolated rat uterus contraction.
1. The effects of diethylstilbestrol (DES, 10(-7)-10(-5) M) and nifedipine (10(-10)-10(-7) M) on KCl (60 mM)-induced tonic contraction in the uterus of ovariectomized and 17 beta-estradiol (0.1 mg/kg/day, s.c.)-, 17 alpha-estradiol (0.1 mg/kg/day, s.c.)-, or progesterone (2 mg/kg/day, s.c.)-treated rats have been assayed. 2. The dose-dependent relaxation produced by nifedipine in ovariectomized rats (EC50 = 5.59 +/- 1.25 x 10(-9) M) is potentiated in uterus of rats treated with 17 beta-estradiol and progesterone (EC50 = 0.59 +/- 0.1 and 0.49 +/- 0.1 x 10(-9) M, respectively) but not in the 17 alpha-estradiol-treated rats (3.01 +/- 0.6 x 10(-9) M). 3. The relaxation produced by DES on ovariectomized rats (EC50 = 0.84 +/- 0.14 x 10(-6) M) is reduced when the rats are treated with 17 beta-estradiol (EC50 = 2.22 +/- 0.2 x 10(-6)M) or progesterone (EC50 = 1.24 +/- 0.08 x 10(-6) M), but unmodified by 17 alpha-estradiol (EC50 = 0.58 +/- 0.01 x 10(-6) M). 4. The nifedipine-induced relaxation is reversed with Bay K 8644 (10(-10)-10(-6) M) in all experimental conditions. However, Bay K 8644 counteracted the relaxation of DES at 45.7% on ovariectomized rats but this was lower than 30% in the other groups. 5. Our results suggest that in ovariectomized rats the effects of both nifedipine and DES are similar, but 17 beta-estradiol and progesterone produce a contrary effect on the relaxation induced by nifedipine and DES (by increasing the nifedipine and decreasing the DES effects).(ABSTRACT TRUNCATED AT 250 WORDS)
Involvement of sodium/calcium exchange in the diclofenac-induced spasmolytic effect on rat uterus.
1. The effect of diclofenac (10-100 microM) on rat uterus contraction and its modification by ouabain (0.1 mM), amiloride (0.1 and 1 mM), ouabain (0.1 mM) plus amiloride (1 mM) and the replacement of sodium by choline have been assayed. 2. Diclofenac produces dose-dependent relaxation of vanadate (0.3 mM)-induced contraction (EC50, 17.3 +/- 1.8 microM). This effect is significantly reduced in choline medium (EC50, 49.1 +/- 4.5 microM) and by ouabain in sodium-medium (EC50, 52 +/- 7 microM). 3. Amiloride displaces, in a dose-dependent way, the diclofenac-induced relaxant effect. However, ouabain plus amiloride did not produce a sinergic effect. 4. Our results suggest that diclofenac produces relaxation of vanadate-induced contraction by activation of Na+/Ca(2+)-exchange.
Calcium-and G-protein-related spasmolytic effects of nonsteroidal anti-inflammatory drugs on rat uterus contractions in vitro.
The effects of the nonsteroidal anti-inflammatory drugs (NSAIDs) acetylsalicylic acid, metamizole, phenylbutazone, indometacin, piroxicam, naproxen, tolmetin, diclofenac, and mefenamic acid on methacholine (10 mumol/l), prostaglandin F2 alpha (1 mumol/l), and KCl (60 mmol/l) induced contractions of isolated rat uterus were assayed. All of these cause a concentration-dependent inhibition of methacholine and prostaglandin F2 alpha-induced contractions with the exception of acetylsalicylic acid, metamizole, and naproxen. All except acetylsalicylic acid and metamizole relaxed in a concentration-dependent manner the tonic contractions induced by KCl. CaCl2 (0.1-10 mmol/l) totally counteracted the relaxant effects of naproxen and tolmetin, but not those of the other NSAIDs. Bay K8644 did not revert the effect of the NSAIDs. Pertussis toxin (50 micrograms/l) did not modify the effect of indometacin, mefenamic acid, and tolmetin, but partially antagonized the effects of diclofenac and naproxen and increased the effect of phenylbutazone and piroxicam. These results suggest that some of the NSAIDs assayed induce smooth muscle relaxation by mechanisms independent of prostaglandin synthesis inhibition, but related to the inhibition of extracellular calcium influx through mechanisms related or unrelated to pertussis toxin sensible G proteins.
Targeted ablation of glia disrupts axon tract formation in the Drosophila CNS.
Glial cells are thought to play a role in growth cone guidance, both in insects and in vertebrates. In the developing central nervous system of the Drosophila embryo, the interface glia form a scaffold prior to the extension of the first pioneer growth cones. Growing axons appear to contact the glial scaffold as the axon tracts are established. We have used a novel technique for targeted cell ablation to kill the interface glia and thus to test their role in establishment of the embryonic axon tracts. We show that ablation of the interface glia early in development leads to a complete loss of the longitudinal axon tracts. Ablation of the glia later in embryonic development results in defects comprising weakening and loss of axon fascicles within the connectives. We conclude that the interface glia are required first for growth cone guidance in the formation of the longitudinal axon tracts in the Drosophila embryo and then either to direct the follower growth cones, or to maintain the longitudinal axon tracts.
Three distinct roles for the engrailed gene in Drosophila wing development.
BACKGROUND: The development of Drosophila includes stages at which the future component parts of the adult seem to be divided into distinct anterior and posterior compartments, with clones of cells restricted by their lineage to only one of the two compartments. The engrailed gene is thought to be a 'selector' gene that controls the expression of other genes to confer a 'posterior identity' on groups of cells that are related to each other by lineage. Consistent with this notion, engrailed encodes a homeo-domain-containing transcription factor that is expressed in all posterior developmental compartments of the fly. In this paper, the processes that are regulated by engrailed during morphogenesis of the fly wing are analyzed. RESULTS: The effects of a total lack of engrailed function in the wing have been analyzed for the first time. This has revealed three different requirements for engrailed during wing development. It has a late role in patterning the wing margin, which includes cells within the anterior compartment. In addition, it is involved in the cell-cell interactions that maintain the expression of the decapentaplegic gene along the antero-posterior compartment boundary; decapentaplegic, in turn, controls growth through a mechanism that depends on the activity of the gene hedgehog, and the maintenance of the compartment boundary depends on these cell-cell interactions. Finally, there is a global requirement for engrailed in the control of growth through a hedgehog-independent mechanism. In fact, cell proliferation is induced after removal of the functions provided by both engrailed and a second gene, patched. CONCLUSIONS: The multiple roles of engrailed and the temporal specificity for each function of the gene suggest that engrailed does not act simply by assigning an identity to cells, as had been supposed previously, but rather that is has more complex roles. Establishment and maintenance of the antero-posterior compartment boundary does not depend exclusively on the engrailed gene product. In addition, engrailed plays a major role in the control of growth by a pathway independent of putative inducing signals.
Dorsal dislocation of the first metatarsophalangeal joint.
We report 3 cases of dorsal dislocation of the first metatarsophalangeal joint treated by closed reduction. Associated dislocation of the sesamoid complex may make reduction difficult. We suggest a modification of Jahss's classification and have confirmed our findings in amputation specimens.