Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “HYPOTHALAMUS”

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 1,675 records · Page 93Linked to original sources
PubMed1992

[The reactions of the viscerosensory neurons of the nucleus solitarius to stimulation of the posterior and anterior hypothalamus].

The "vagal" neurons of the solitary tract nucleus responded to stimulation of anterior and posterior hypothalamus in 78.7 and 27.6 per cent, resp., the responses being mainly of the activation type. The descending effect from the hypothalamus involved primary as well as secondary "vagal" neurons. The responses were of mono-, oligo- and polysynaptic nature.

Action Potentials↗
PubMed1992

Immunocytochemical localization of GnRH in the hypothalamus of the bat Miniopterus schreibersii schreibersii.

The distribution of gonadotropin-releasing hormone (GnRH) has been examined in the hypothalamus of adult female bats, Miniopterus schreibersii schreibersii, along annual reproductive cycle by means of light-microscopic immunocytochemistry. GnRH-immunoreactive cells are localized throughout the medial basal hypothalamus, being specially numerous in the arcuate nucleus. They are generally bipolar or monopolar neurons with smooth contour, although spiny cells were also found exclusively in the arcuate nucleus from periovulatory bats. Depletion in both number and immunocytochemical labelling of GnRH perikarya is detected in pregnant and lactating bats. GnRH-immunoreactive fibers are distributed in the internal layer of the median eminence and the infundibular stalk. Pregnant and lactating animals show lower GnRH fibers content and a less intense labelling than in periovulatory and hibernating conditions. The results suggest that changes in the secretory activity of GnRH neurons may be associated with hibernation and delayed implantation that suffer these mammalian species.

Animals↗
PubMed1991

[Effects of left atrial stretch and carotid occlusion on the single unit activity of anterior and posterior hypothalamus in cat].

The effects of left atrial stretch (AS) and carotid occlusion (CO) on the single unit activity of anterior and posterior hypothalamus (AH and PH) were investigated in 40 urethan-chloralose-anesthetized cats. A total of 185 units with spontaneous discharge were recorded. 46.3% (44/95) of the neurons in AH and 23.3% (21/90) of those in PH were responsive to AS. Majority of the neurons affected by AS exhibited a decrease in firing rate. A few units only showed transient response during the onset and release of AS (on-off response). Out of the 185 units, 85 units were tested by both AS and CO, and 15 units (17.6%) were responsive to both interventions. Among them 11 (73.7%) were inhibited by AS and excited by CO. From the results mentioned above, it is suggested that: (1) AS may exert an inhibitory effect on the activity of neurons in AH. (2) The activity of neurons in PH may be also affected by AS. (3) The inputs from the atrial volume receptor and carotid baroreceptor converge on the same neuron of the hypothalamus.

Animals↗
PubMed1975

Stress-induced ACTH release after removal of the hypothalamus in rats with atrophied neural lobe.

Twenty-four hours after isolation of the pituitary by surgical removal of the medial hypothalamus, i.e. in rats with pituitary island, E. coli endotoxin significantly increased the plasma corticosterone level. Atrophy of the neural lobe, due to pituitary stalk section performed one month prior to removal of the medial hypothalamus, did not prevent the increase of ACTH release by E. coli endotoxin. E. coli endotoxin-induced ACTH release in MBH-deprived animals does not appear to be a function of mechanisms operating only in the innervated lobe.

Adrenocorticotropic Hormone↗
PubMed1977

[Role of the medial hypothalamus in regulating the pituitary-adrenocortical system].

In unrestrained rabbits, inhibition of ACTH release as determined by changes in plasma levels of corticosteroids, followed electrolytic lesion of the dorso-and ventromedia nuclei of the hypothalamus. Electric stimulation of the dorsal midbrain tegmentum had activated ACTH prior to lesion; after the lesion of the dorso-and ventromedial nuclei the stimulation produced no response. The dorso-and ventromedial nuclei of the hypothalamus are essential for basal and induced secretion of the ACTH.

Adrenal Cortex Hormones↗
PubMed1989

[The destruction of perikaryas of the mesencephalic reticular formation and the posterior hypothalamus does not cause major disorders of awakening in the cat].

Ibotenic acid microinjections have been realized at the level of the mesencephalic reticular formation and the posterior hypothalamus in 7 cats. This technique has led to a quasi-total destruction of cell bodies in the two areas (including the histaminergic neurons). 2 to 3 days after such lesions, there were no major effects on behavioral waking. These results do not favor the hypothesis of the existence of a waking system at the level of the mesencephalic reticular formation and/or posterior hypothalamus.

Animals↗
PubMed1977

Hypersensititivity of rats to anorectic agents after lesions in the ventromedial hypothalamus.

Anorectic agents such as d-amphetamine and fenfluramine showed a remarkably higher effect in rats with hyperphagia after lesioning the ventromedial hypothalamus. A persistence and even a further increase of the hypersensitivity to anorectics was observed in animals which, eight months after ventromedial hypothalamus-lesioning, resumed almost normal eating patterns. The appearance of the hypersensitivity to anorectic agents after lesioning and its persistence or enhancement in long-term operated animals are interpreted in terms of the mechanisms contributing to the neural reorganization of the control of the feeding center after suppression of ventromedial inhibitory influences.

Animals↗
PubMed1987

Aminergic neurons in the hypothalamus of the dogfish, Scyliorhinus canicula L. (Elasmobranch). A histofluorescence study.

Aminergic neurons of the hypothalamus of Scyliorhinus canicula were studied using formaldehyde-induced fluorescence. An aminergic organ of the preoptic recess (PRO) consists of both cerebrospinal fluid (CSF)-contacting and non-contacting green-yellow fluorescent neurons of bipolar or multipolar morphologies. Caudal to the optic chiasma a group of faint fluorescent neurons is located among the fibres of the commissura transversa. In the posterior hypothalamus the infundibular wall has numerous aminergic CSF-contacting neurons along lines of diverticles. Scarce CSF-contacting neurons are also found in the roof and floor of the recesses of the inferior hypothalamic lobes. The folded posterior recess has a very high number of aminergic CSF-contacting neurons of bipolar shape. Its coarse layer of cell bodies is covered by a large amount of fluorescent fibres which form a conspicuous cap-like band. These structures are discussed from a comparative point of view in relation with aminergic hypothalamic systems of other anamniote vertebrates.

Animals↗
PubMedDate not supplied

Activity of noradrenergic neurons of medial-basal hypothalamus of female rabbits in some stages of reproduction.

Activity of noradrenergic neurons of medial-basal hypothalamus of female rabbits in some stages of reproduction. Acta Physiol. Pol., 1978, 29 (2): 111--115. The differences were found in the activity of noradrenergic neurons of medial-basal hypothalmus (MBH) estimated by the analysis of metabolism of intraventricularly infused 3H-noradrenaline (3H-NA) in various stages of reproduction in female rabbits. The gonadal hormones and especially 17beta-estradiol seem to be involved in this activity. The rapid disappearance of 3H-NA from MBH, found immediately after mating, implicates an involvement of noradrenaline in the process of Gn-RHs release form the rabbit hypothalamus.

Animals↗
PubMed1985

Gudden's tegmental nuclei and their connections to the hypothalamus and the reticular formation. II. An experimental study using retrograde double labelling with HRP and iron-dextran in the rat.

12 rats in double experiments were studied for the simultaneous retrograde transport of HRP and Dextran-fer from injections in the mamillary body and in the reticular formation or in selected diencephalic structures into the cells of Gudden's tegmental nuclei. The results of this particular study corroborated the findings of retrograde transport in single experiments (see Part I) showing all the cells of ventral Gudden's nucleus as projecting into the mamillary body, the cells of its peripheral parts as projecting also via a collateral to the lateral hypothalamus, and the cells of its central parts as projecting, in addition, via a collateral to the reticular formation (ncl. pedunculo-pontinus and ncl. pontis oralis). Cells of the ventral part of the ncl. dorsalis tegmenti Guddeni project into the lateral mamillary body and some of then also through a collateral into the whole of the hypothalamus. Part of its cells project independently into the RF (ncl. pontis oralis). The dorsal part of the ncl. dorsalis tegmenti Guddeni projects bilaterally to the ncl. pontis oralis.

Animals↗
PubMed1985

[Effect of the limbic cortex and hypothalamus on the activity of the medullary respiratory neurons].

Effects of stimulation of anterior limbic cortex (areas 24 and 32) and postero-lateral hypothalamus on the spike discharges of bulbar respiratory neurons were studied in anesthetized cats with normal respiration. The effects could be similar or different. The responses of respiratory neurons to stimulation of the hypothalamus were more pronounced and had lower thresholds than those to stimulation of the anterior limbic cortex. The effects of both structures on the spike activity of inspiratory and expiratory neurons have a generalized character (facilitatory as well as inhibitory). Possible mechanisms of the respiration control by the limbic structures are discussed.

Action Potentials↗
PubMed1977

[Presence of neurons synthesizing LH-RH in the anterior hypothalamus of the duck (Anas platyrhynchos)].

Using histochemical techniques with LH-RH anti-serum, a large number of LH-RH producing neurons were identified in the Duck hypothalamus, under different physiological conditions. The LH-RH pericaryas were localized in a well delimited area of the anterior hypothalamus, including the dorsal part of the periventricular preoptic nucleus. The LH-RH containing axons were directed downwards towards the infundibulum, and terminated within the external layer of the rostral and caudal median eminence, in close vicinity to the capillaries of the pituitary portal system.

Animals↗
PubMedDate not supplied

[Role of serotonin receptors of the medial-basal hypothalamus in the mechanisms of negative feedback of the hypophyseal-testicular complex].

Administration of serotonin into the lateral ventricle of the brain of male rats, against the background of complete isolation of the medial-basal hypothalamus was accompanied by the block of the compensatory elevation of the blood testosterone level following unilateral castration. Experiments with local serotonin administration into the hypophysial region of the hypothalamus of hemicastrated rats indicated that the inhibitory effect produced by the excitation of the serotonin receptors of this region on the mechanism of the negative feedback of the hypophysis-testicular system was realized at the arcuate nuclei level.

Animals↗
PubMed1984

[Interrelations between the hypothalamus and the amygdaloid complex in the regulation of motor function of the digestive tract].

In chronic experiments on dogs, preliminary stimulation of corticomedial and parvocellular basal nuclei of amygdala augmented the motor responses of the gastro-intestinal tract to subsequent stimulation of median hypothalamic structures and weakened the inhibitory effects of posterior hypothalamic structures on motility of the digestive tract. After preliminary stimulation of the hypothalamus, the motor responses of stomach and small intestine to subsequent stimulation of corticomedial and parvocellular basal nuclei of amygdala were enhanced. The data obtained suggest existence of a complex functional hypothalamo-amygdaloid interaction, the hypothalamus with its basic mechanisms of regulation of motor function of the digestive tract playing the leading part in this interaction.

Amygdala↗
PubMed1978

[Characteristics of the estradiol receptor system of the anterior hypothalamus and adenohypophysis in guinea pigs].

The presence of a specific receptor system (E2-R) wthith low capacity and high stability of the E2-R complex formation was shown in the guinea pig adenohypophysis and anterior hypothalamus cytozols under the vivo and in vitro conditions. Some parameters of the physico-chemical properties of the E2-R system in these tissues differed. The adenohypophysis and the anterior hypothalamus receptor complexes formed at different temperatures were not identical.

Animals↗
PubMed1982

[Existence of neurotensin receptors in the caudate nucleus and posterior hypothalamus].

Chronic experiments in dogs revealed that administration of neurotensin (3 and 10 mkg in 1.5 mkl) into the caudate nucleus altered the parameters of conditioned and unconditioned food reflexes: shortened the latency by 31% and augmented the reflexes by 56%. The microapplication of neurotensin in the same dosage into the posterior hypothalamus increased the stomach secretory function induced by histamine administration. The caudate nucleus and the hypothalamus seem to contain cells which have the receptors for neurotensin and take part in the mechanisms of conditioning and central influences on the digestive system's organs.

Animals↗
PubMed1983

[Effect of arecoline on neuronal activity in the posterior hypothalamus of rabbits with experimental fever].

It has been found in experiments on unanesthetized rabbits that arecoline administered to the lateral ventricle of the brain produced an action which was opposite to that of leukocytic pyrogen. It inhibited the activity of individual neurons of the posterior hypothalamus and decreased the body temperature, with this decrease being attended by the signs of intensified heat emission. Arecoline injection coupled with the central action of PGE2 was followed by an increase in the neuronal activity in the posterior hypothalamus and reduction of hyperthermal response.

Action Potentials↗
PubMedDate not supplied

[Ascending effects of the posterior portion of the hypothalamus on electrical activity of the cerebral cortex in the rabbit during postnatal ontogeny].

Effects of electrostimulation of the posterior hypothalamus on the neocortical activity of non-anesthetized freely-moving rabbits in the postnatal ontogenesis was studied by means of electroencephalografic method. In rabbits of the first postnatal week the electrostimulation evoked in the neocortex mainly an activation reaction of synchronized character. From the second week of the postnatal age the electrostimulation caused in the EEG of the neocortex a desynchronization reaction. The data obtained show that the posterior hypothalamus may take part in the regulation of the state of sleep and wakefulness in rabbits from the first week of the postnatal age.

Animals↗