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PubMed1979

Study of electrical activity in the area of the hypothalamic ventromedial nucleus and the lateral hypothalamus of rats fed on a high protein and high fat diet.

The authors studied bioelectric potentials in the area of the hypothalamic ventromedial nucleus and the lateral hypothalamus of rats fed on a standard, a high protein and a high fat diet. On the first 3--6 days after changing from the standard to the high fat and high protein diets, a decrease in the amplitude of electrical activity was recorded in both the areas in question. It was also found that the frequency of electrical activity in the hypothalamic ventromedial nucleus or the lateral hypothalamus rose, after 3 days administration of the high fat or the high protein diet, in correlation to the type of diet, and that, in the frequency spectrum, a change occurred in the proportion of basic frequency in relation to superimposed frequencies distorting it. It was further found that there was a permanent difference between the amplitude of electrical activity in the lateral hypothalamus and the hypothalamic ventromedial nucleus.

Animals↗
PubMedDate not supplied

[Effect of external ionizing radiation on morphofunctional indices of the hypothalamus, hypophysis and adrenal glands].

The laboratory rats exposed to one-time external ionizing radiation have been found to have phase changes of morphofunctional and secretory cells activity of hypothalamus, hypophysis, cortex and medullary of adrenal glands. The first phase called reactive (3-7 days) is characterized by enhancing energy-producing, protein-synthesizing and secretory functions of secretory sells of hypothalamus supraoptic nucleus, corticotrophic cells of adenohypophysis, adrenocorticytes of cortex and adrenocytes of medullary of adrenal glands. The second phase of dystrophic changes (7-14) is characterized by different degree of distrophic-destructive changes. The third phase (14-1 month) is characterized by compensatory adaptative and recovery processes during which we can see on the background of dystrophic changes the processes of intracellular reparative regeneration. The fourth phase (1-3 months) is characterized by virtually complete recovery of morphofunctional and secretory activity of most cells of hypothalamus, hypophysis and adrenal glands.

Adrenal Glands↗
PubMedDate not supplied

The vasotocinergic system in the hypothalamus and limbic region of the budgerigar (Melopsittacus undulatus).

We report a morphological and biochemical analysis on the presence, distribution and quantification of vasotocin in the hypothalamus and limbic region of the budgerigar Melopsittacus undulatus, using immunohistochemistry on serial sections and competitive enzyme linked immunoadsorbent assay measurements on tissue extracts. Analysis of the sections showed large vasotocin-immunoreactive neurons in three main regions of the diencephalon, of both male and female specimens. Vasotocinergic cell bodies were located in the ventral and lateral areas of the hypothalamus, dorsal to the lateral thalamus and medial to the nucleus geniculatus lateralis. Immunoreactive neurons were placed also periventricularly, close to the walls of the third ventricle, at the level of the magnocellular paraventricular nucleus. Well evident bundles of immunoreactive fibers were placed ventral to the anterior commissure in the same regions of the hypothalamus and thalamus where vasotocinergic perikarya are localized. Fibers were identified close to the third ventricle, and in the lateral hypothalamic area along the lateral forebrain bundle. In contrast to what reported for other oscine and non-oscine avian species, we were not able to identify immunopositive neurons in any region above the anterior commissure, or detect relevant differences on the distribution of the vasotocin immmunoreactivity between sexes. Competitive enzyme linked immunoadsorption assay and image analysis of the extension of immunoreactivity in the tissue sections were consistent with the qualitative observations and indicated that there is no statistically significant dimorphism in the content of vasotocin or in the location and distribution of vasotocinergic elements in the investigated areas of male and female parrot brains.

Animals↗
PubMedDate not supplied

Histamine-induced cyclic AMP formation in the chick hypothalamus: interaction with vasoactive intestinal peptide.

Effects of histamine (HA) on cyclic AMP production and its action upon the effects evoked by vasoactive intestinal peptide (VIP) were studied in the chick hypothalamus. HA (0.1-1000 microM) potently stimulated cyclic AMP formation in the hypothalamic slices, reaching maximal effect (2.5-3.5-fold increase) at a 100 microM concentration, and displaying an EC50 value of approximately 6.5 microM/ The stimulatory action of HA was mimicked by agonists of HA receptors, with the following rank order of potency: HA>4-methylHA (H2)>or=Nalpha,Nalpha-dimethylHA (H3>>H1=H2)>or=2-methylHA (H1)>>amthamine (H2)>>dimaprit (H2) approximately tele-methylHA. The HA (100 microM)-evoked increase in cyclic AMP production was concentration-dependently antagonized by selective H2-HA receptor blockers (aminopotentidine>>cimetidine>or=ranitidine>>zolantadine) and was not affected by mepyramine and thioperamide, a selective H1- and H3-HA receptor antagonist, respectively. The pharmacological profile of HA receptors linked to the cyclic AMP-generating system in the chick hypothalamus indicates that they represent either an avian-specific H2-like HA receptor or a novel subtype of HA receptors. Chicken VIP (cVIP; 0.1-3 microM) potently stimulated cyclic AMP synthesis in the chick hypothalamus in a concentration-dependent manner. A combination of cVIP with HA produced cyclic AMP response more than additive, and such a synergistic interaction was antagonized by ranitidine. It is suggested that in the avian brain HA and VIP may play in concert to regulate neuroendocrine processes.

Animals↗
PubMedDate not supplied

[The role of the lateral and medial hypothalamus in reproducing a motor reaction as the signal during the acquisition of classical conditioned reflexes].

In experiments on three dogs there was shown that testing electrostimulation of the lateral hypothalamus reproduced the motor reaction which is a signal stimulus at elaboration of classic alimentary conditioned reflexes (CRs) and did not reproduce it at elaboration of classic defensive CR. Testing electrostimulation of medial parts of the hypothalamus reproduced, as LH electrostimulation the "signal" motor reaction, but in less percentage of cases, during elaboration of classic alimentary CRs and did not reproduce it at elaboration of classic defensive CRs. The reproduction of the signal motor reaction at LH electrostimulation is connected with activation of backward conditioned connection from motivation structures of the hypothalamus to representation of the signal stimulus in the motor cortex.

Animals↗
PubMed2005

[The effect of four kinds of traditional Chinese herbal compound on the experimental acute stress behaviors and the hypothalamus-pituitary-adrenal gland axis].

OBJECTIVE: To study the effects of four kinds of traditional Chinese herbal compound, Sini powder, Banxiahoupu soup, Ganmaidazao soup and Guizhigancaolonggumuli soup, on the experimental acute stress behaviors and the hypothalamus-pituitary-adrenal gland axis. METHOD: Rats were divide into 7 groups: normal group, model 1 and 2 groups, Sini powder group, Banxiahoupu soup group, Ganmaidazao soup group, and Guizhigancaolonggumuli soup group. The behaviors of the rats and their CRH of the hypothalamus, ACTH of plasma and CORT of serum (by the means of radio-immunity) were detected. RESULT: Sini powder could reduce the crossing times of open-field test( P < 0.01) and the contents of CRH and CORT (P < 0.01, P < 0.05); Banxiahoupu soup could extent the still time of tail-hanging test ( P < 0.05) and the content of CRH (P < 0.05); Ganmaidazao soup could prolong the still time (P < 0.05) and reduce the struggle times (P < 0.01) of tail-hanging test and reduce the contents of CRH, ACTH and CORT (P < 0.01, P < 0.05); Guizhigancaolonggumuli soup could reduce the crossing times of open-field test (P < 0.01) , extent the still time (P < 0.05) and reduce the struggle times ( P < 0.01) of tail-hanging test of tail-hanging test, also reduce the contents of CRH, ACTH and CORT (P < 0.01, P < 0.05). CONCLUSION: The four kinds of traditional Chinese herbal compound can increase the ability of anti stress by affect the different taches of the hypothalamus-pituitary-adrenal gland axle and change the stress behaviors, which are based on their respective functions of regulating Qi, dispersing phlegm, tonifying Qi and warming Yang.

Adrenocorticotropic Hormone↗
PubMed2006

Expression of NPY-immunoreactive neurons in the hypothalamus of the cycling ewe.

The purpose of the study was to localise neuropeptide Y (NPY) immunoreactive (ir) neurons in the hypothalamus during two phases of the oestrous cycle in the ewe. Hypothalamic tissue was collected from Polish Merino ewes (n=8) in the follicular (15th day) and preovulatory (17th day) phases of the oestrous cycle. NPY-ir neurons were detected in the hypothalamus using immuohistochemistry followed by image analysis; positive staining was expressed as the percentage of stained area and optical density. Two populations of the NPY-positive neurons were detected and evaluated in the infundibular and periventricular nuclei of the hypothalamus. The population of NPY-ir neurons located in the infundibular nucleus exhibited a prominent expression of NPY immunoreactivity in the perikarya and fibres only during the preovulatory phase. Both, percent area and the optical density of NPY immunostaining measured in this area were higher (P < 0.01) in the preovulatory than in the follicular phase. Another population of NPY-ir neurons was localised in the periventricular nucleus and did not show any changes during the two phases of the cycle. The present study suggests that NPY-ir neurons present in the infundibular nucleus can play a role in the preovulatory GnRH discharge from the median eminence.

Animals↗
PubMed2006

[Cytosine demethylation in the tyrosine hydroxylase gene promoter in the hypothalamus cells of the rat brain under the action of an aminoadamantane derivative Ladasten].

In our previous study of mechanisms of pharmacological activity of a derivative of 2-aminoadamantane, Ladasten, we have shown more than a twofold increase in the mRNA level of the tyrosine hydroxylase (TH) gene in the rat brain hypothalamus 1.5-2 h after a single administration of this substance. In the present study, we employed the bisulfate sequencing technique to detect changes of GpG islands methylation status in the TH gene 5'-flanking region (-650 + 84) in hypothalamus cells of control and experimental rats after a single exposure to Ladasten. Ladasten was shown to increase frequency of cytosine demethylation in binding sites of some transcription factors or in neighboring motifs. It is suggested that the Ladasten-induced increase of TH gene transcriptional activity in rat hypothalamus is associated with cytosine demethylation in CpG islands in some regulatory gene elements.

Adamantane↗
PubMed2006

[A case of primary central nervous system malignant lymphoma developing from the optic chiasma and hypothalamus].

A 63-year-old woman was admitted to our hospital with a 1-month history of visual field defect and reduced bilateral visual acuity. Neurological examination revealed enlargement of bilateral central scotoma and blurred vision, and brain MRI showed masses in the optic chiasma and right hypothalamus on Ti-weighted image with contrast enhancement. Although the patient was treated with high-doses of methylprednisolone four times, the masses spread to the right internal capsule and the vicinity of the right lateral ventricle. An open biopsy was performed and microscopic examination of the sample revealed lymphoplasmacytic lymphoma. Although primary central nervous system lymphoma (PCNSL) developing from the optic chiasma and hypothalamus is rare, PCNSL should be considered in patients with multiple lesions in the optic chiasma and hypothalamus.

Brain Neoplasms↗
PubMedDate not supplied

[The delta sleep-inducing peptide as a factor enhancing the content of substance P in the hypothalamus and the resistance of rats to emotional stress].

The influence of the delta-sleep inducing peptide (DSIP, 60 and 120 nmol/kg, intraperitoneally) on the content of substance P (SP) in rats hypothalamus was studied on males of August line. DSIP administration significantly increased the mean SP content in the hypothalamus and also its content in animals, stable and predisposed to emotional stress. Daily DSIP administration before putting the rats in conditions of stress increased the SP content in the hypothalamus decreased at the emotional stress. Preliminary single DSIP administration to the animals subjected to stress also increased the SP content. Single DSIP administration in a dose of 60 nmol/kg sharply reduced classical stress manifestations, such as hypertrophy of adrenals and thymus involution.

Animals↗
PubMed1991

Cytoarchitectonic pattern of the hypothalamus in the catfish, Clarias batrachus (Linn.).

The hypothalamus of the catfish, Clarias batrachus has been investigated to reveal the organization of various parvocellular (aldehyde fuchsin-negative) nuclear complexes and to suggest homologies. The hypothalamus of C. batrachus can be divided into the preoptic area, postoptic area, tuberal area and the laterally placed inferior lobes. Application of cytoarchitectonic criteria permits the delineation of 9 distinct nuclear complexes in the preoptic area extending along the periventricular margin of the preoptic recess. The postoptic area is represented by only two nuclear groups, the nucleus postopticus lateralis and the nucleus of the horizontal commissure. The tuberal area consists of as many as 14 nuclei, some are divisible into subnuclei, arranged in an elaborate pattern. The nucleus lateralis tuberis is located in the mid-ventral margin of the tuberal area and revealed two subdivisions, the pars anterior and pars posterior. At the mid-tuberal level, the nucleus anterior tuberis is well-developed and revealed dorsal, ventral and lateral subdivisions. The paraventricular organ is encircled by nucleus of the paraventricular organ. The conspicuous lateral recesses are flanked dorsally by nucleus recessus lateralis superior and ventrally by nucleus recessus lateral by nucleus recessus lateralis superior and ventrally by nucleus recessus lateralis inferior. In the caudal tuberal area, in close proximity of the pituitary, the nucleus arcuatus hypothalamicus is described for the first time. The recessus posterioris is encircled by nucleus recessus posterioris. The inferior lobes are massive and each consists of 7 well-defined nuclear complexes. The nucleus lobi inferioris centralis is represented by giant-sized cells clustered in the center of the lobes. The periventricular nucleus of the inferior lobes occupies the area surrounding the recesses of the inferior lobes. The hypothalamus shows 4 circumventricular organs. The organum vasculosum laminae terminalis is situated along the ventral wall of the preoptic recess. While the paraventricular organ is located in the dorsal wall of the third ventricle, the posterior recess organ is located in the postero-ventral wall of the third ventricle. The saccus vasculosus is small, capsule-like and located caudally in between the two mamillary nuclei.

Animals↗
PubMed1991

Aging and the hypothalamus-pituitary-adrenocortical axis, with special reference to the dog.

Aging affects the hypothalamus-pituitary-adrenocortical (HPA) system in various ways. It affects the receptors for glucocorticosteroids in the limbic system, the hypothalamus and the pituitary; the basal and stress-induced secretion of proopiomelanocortin-derived peptides and glucocorticoids; and the neuronal integrity, especially in the hippocampus. The homeostatic actions of glucocorticoids occur through the glucocorticoid and the mineralocorticoid receptors. It has been hypothesized that the balance between these two receptors, which are co-localized in the hippocampus, determines the basal HPA activity and the magnitude of the response to challenges. Feedback actions of glucocorticoids are mediated via glucocorticoid receptors in the hypothalamus and the pituitary. In aged rats many changes in the binding capacity of the mineralocorticoid receptor and glucocorticoid receptor and in the regulation of the HPA activity have been reported, but the findings often seem contradictory. The only consistent finding has been that the binding capacity of mineralocorticoid receptor in the hippocampus is reduced. The number of glucocorticoid receptors may be increased, reduced or unchanged in senescent rats. In old dogs the receptor changes were largely confined to mineralocorticoid receptor, there being a 60% reduction in the binding capacity in the limbic system, but glucocorticoid receptor was unchanged in all brain regions. Senescent dogs also had an increased basal secretion of ACTH, and of cortisol. The old dogs had exaggerated responses to stress and to administered corticotropin-releasing hormone, but the termination of the response by the feedback mechanism was unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex↗
PubMed1991

The trigger for parturition in sheep: fetal hypothalamus or placenta?

The fetal pituitary-adrenal axis plays a pivotal role in the mechanisms leading to parturition in sheep. Fetal cortisol concentrations gradually increase in the last 15 days before term, with a marked increase occurring in the last 3-4 days. Some mechanism causes a marked increase in the stimulatory drive to the fetal pituitary resulting in increased secretion of ACTH from the pituitary, and subsequent cortisol secretion from the adrenal gland. In this paper we discuss the roles of the hypothalamus and placenta in triggering the onset of labour in sheep. We have shown that prostaglandin E2 can stimulate the release of ACTH and cortisol in the intact fetus and we believe that this could be mediated by the release of CRH and AVP. Although CRH and AVP are present in the fetal hypothalamus and are capable of being released, these factors may not be released until approximately 135 days of gestation. One fundamental question in relation to parturition remains unanswered: how are the high concentrations of cortisol in fetal plasma sustained given that cortisol has an inhibitory feedback effect on the release of CRH and ACTH secretion? We discuss the possibility that the placenta provides an additional trophic drive to both the pituitary and adrenal glands which contributes towards the sustained elevated cortisol concentrations needed to initiate parturition. The placenta may initiate the hypothalamus and PGE2 and/or CRH, secreted by the placenta, may stimulate pituitary ACTH release.

Animals↗
PubMed1990

[A method for determining the angiotensin-converting enzyme activity in the rat hypothalamus and hypophysis].

A method for determination of the activity of angiotensin-converting enzyme (ACE) in the hypothalamus and hypophysis of the rat was provided. Membrane-bound enzyme was extracted from tissues by twice homogenization and centrifugation after solubilization of membrane structures with the detergent triton X-100. Protein concentrations of tissue extracts and time of incubation, at which there was linear generation of dipeptid his-lev in the course of the enzymic reaction as at the same time its degradation from tissue peptidases was under 10%, were between 0.16 and 0.35 mg/ml for the hypothalamus and between 0.07 and 0.18 mg/ml for the hypophysis with duration of incubation between 15 and 30 min. Under these conditions the enzymic activity was determined by a substrate-fal-his-lev, amounting to 18.22%-1.3 and 96.22-42 nmol/min/mg of protein (x-SEM) for the hypothalamus (n = 18) and hypophysis (n = 30) respectively. The coefficients of variation of the enzymic analysis were determined for a series in a day (1.37%) and for a series in time (9.59%). Hydrolyzing activity synonymously identified as ACE was differentiated from other tissue peptidildipeptide hydrolases by the following three criteria: hydrolyzing activity in respect to the specific for ACE artificial substrates; activation of enzymic action by Cl-; inhibition of the activity by converting inhibitors captopryl and MK 422 as well as by the helatic agent EDTA-Na2.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1990

[Effect of monoamine neurotransmitters in the hypothalamus in a cortisol-induced rat model of yang-deficiency].

Eight monoamine neurotransmitters in hypothalamus of normal and cortisol-induced Yang-deficiency rats were measured with HPLC-ECD. These neurotransmitters included: (1) Noradrenaline (NA); (2) Adrenaline (A); (3) 3-methoxy-4-hydroxyphenyl glycol (MHPG); (4) 3,4-dihydroxyphenylacetic acid (DOPAC); (5) Dopamine (DA); (6) 5-hydroxyindole-3-acetic acid (5-HIAA); (7) Homovanillic acid (HVA); and (8) Serotonin (5-HT). With the mobile phase of 10% methanol-0.15 M chloroacetic acid-sodium hydroxide buffer, the neurotransmitters might be well separated, the sensitivity was similar to that of gas chromatography-mass spectrogram with the lower limit of 0.1 ng, this assay was simple and might be accomplished with half an hour. The Yang-strengthening Chinese herbs Radix Aconiti Praeparata, Cortex, Cinamomi, Epimedium brevicorum and Herba Cistanchis were used in the study and the following were founded: (1) In the hypothalamus of cortisol-induced Yang-deficiency rat NA decreased and a increased when compared with that of the normal controls (both P less than 0.05). (2) After 4 weeks of administration of Yang-strengthening herbs, the NA and A of the Yang-deficiency rats returned to nearly normal and it suggested these herbs have the effect of "supporting the right and recovering the source"; DA markedly increased both in control rats and Yang-deficiency rats (P less than 0.05, P less than 0.001 respectively); DOPAC obviously decreased both in control rats and Yang-deficiency rats (P less than 0.001); 5-HT and 5-HIAA increased in the control rats (both P less than 0.001) and HVA significantly decreased in Yang-deficiency rats. (3) The ratio of DA/DOPAC and 5-HT/5-HIAA markedly increased both in the control and Yang-deficiency rats after using Yang-strengthening herbs (P less than 0.01-0.001) and it suggested Yang-strengthening herbs could inhibit the activity of monoamine oxidase in hypothalamus.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1990

[Serotonin of hippocampus and hypothalamus taking part in the analgesic effect of adrenocorticotropic hormone in rats].

The effects of ip intra-PAG injection of ACTH on serotonin (5-HT), norepinephrine (NE) contents of hippocampus and hypothalamus and pain threshold were investigated. The results showed: (1) After ip ACTH, the pain threshold, the contents of 5-HT of the two brain regions and the NE content of hippocampus were markedly elevated. Prior destruction of periaqueductal gray (PAG), the elevation of pain threshold and the increase of the 5-HT contents of two brain regions due to ip ACTH were completely abolished, while the effect of ACTH in elevating NE content of hippocampus still persisted. (2) After intra-PAG injection of ACTH, the pain threshold and the 5-HT contents in hippocampus and hypothalamus were significantly increased, however, the NE levels in hippocampus and hypothalamus showed no significant changes. The analgesic effect of the intra-PAG injection of ACTH was prevented by icv LSD, but not by naloxone, atropine, hexamethonium and phentolamine. (3) After icv ACTH, the pain threshold did not change. These results suggest that the serotoninergic system may be activated by PAG for mediation of ACTH-induced analgesia.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

[The uptake of 3H-serotonin by neural elements of the rat hypothalamus in ontogeny].

Development of serotoninergic system of rat hypothalamus has been studied. The level of its maturity was measured by specific absorption of 3H-serotonin by hypothalamus of fetuses (days 16-20 of intra-uterine development), newborn (9 days after birth) and adult rats. Inhibitors of specific serotonin capture by serotoninergic neural elements (cocaine, fluoxetin and cytalopram) were used in control experiments. Specific uptake of 3H-serotonin by hypothalamus was detected on day 16 of intra-uterine development. It increased twice by day 18 and remained unchanged until birth. No statistically significant increase of 3H-serotonin uptake was detected in newborn and adult animals.

Aging↗
PubMed1990

[Formation of S-100 containing cells of the hypothalamus and adenohypophysis in normal ontogenesis and in protein deficiency].

By means of the indirect immunohistochemical method distribution of S-100 containing cells has been studied in sections of the mediobasal hypothalamus (astrocytes) and adenohypophysis (follicular-stellate cells) in newborn, 10- and 21-day-old rats under normal development and under protein insufficiency. For this the animals are given the diet containing 6% of protein (control--25% of protein). S-100 containing cells are revealed in the hypothalamus and adenohypophysis in 10- and 21-day-old animals. In the brain of the newborn rats S-100 immunoreactive cells are not revealed. At the ultrastructural level the diaminobenzidine (DAB) reaction products in the immunoreactive cells are revealed diffusely along the whole cytoplasm of the cells, in nuclei the DAB reaction products are absent. Part of S-100 containing cells is essentially lowered, comparing with the control. In the rat adenohypophysis part of S-100 containing cells from the 10th up to the 21st day also decreases. Unlike the hypothalamus, however, content of cells, immunopositive to S-100 exceeds the analogous index in the control rats of the corresponding age groups.

Age Factors↗