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PubMed1978

Neuroradiologic study of hamartomas of the tuber cinereum and hypothalamus.

Five cases, four histologically proven, of hamartoma of the tuber cinereum and hypothalamus in children are reported. The ages of the patients range from 2 to 12 years. Three cases had pubertas praecox, and in all of these the hamartoma was located in the basal cistern between the chiasm and pons and had a collar button shape and size typical of hamartoma of the tuber cinereum. In the third case, a huge calcified mass in the suprasellar region was initially thought to be craniopharyngioma. The fourth case had a hamartoma within the substance of the hypothalamus and presented with hyponatremia and temporal lobe seizures.

Age Factors↗
PubMed1976

Differential effects of para-chlorophenylalanine on self-stimulation in caudate-putamen and lateral hypothalamus.

Rats were prepared with chronic bipolar electrodes aimed at either the caudate-putamen or lateral hypothalamus and those displaying consistent self-stimulation were given additional training at half-maximal current intensities. All subjects received an intragastric injection of para-chlorophenylalanine (400 mg/kg) and self-stimulation tests continued until pre-injection rates were re-established. Responding in both brain areas was suppressed 24 h after drug treatment. The next day, self-stimulation rates in the hypothalamus increased to 115% of pre-drug levels reaching a level of 180% by the third day of post-drug testing. In contrast, self-stimulation of sites in the neostriatum continued to decline, with minimal levels reaching 48% of control on the fourth post-drug day. Self-stimulation rates in both groups had returned to control levels by post-drug day 6. These data indicate that the role of serotonergic mechanisms in brain stimulation is locus specific, and that the specific nature of this role may be determined by interaction with other neurochemical systems. The possible interaction between dopaminergic and serotinergic mechanisms in the neostriatum is discussed as a model of self-stimulation in this region of the brain.

Animals↗
PubMed1980

Effect of clonidine and phentolamine on self-stimulation behavior in the dorsal and ventral regions of the lateral hypothalamus in mice.

The effects of IP injections of increasing doses of clonidine and phentolamine on self-stimulation behavior (ICSS) in the dorsal and ventral regions of the lateral hypothalamus were studied in C57BL/6 mice. Clonidine specifically stimulates alpha-noradernergic receptors and has two distinct effects on ICSS. Ventral hypothalamic ICSS is immediately depressed at low doses (5 microgram/kg) whereas dorsal ICSS exhibits a discrete increase. At higher doses, ICSS is perturbed at both sites. Phentolamine is a specific blocking agent of alpha-noradrenergic receptors and depresses dorsal ICSS more than that of the ventral region. These observations clearly indicate a noradrenergic influence in the dorsal region of the hypothalamus.

Animals↗
PubMed1980

Effects of Lilly 110140 (flouxetine) on self-stimulation behavior in the dorsal and ventral regions of the lateral hypothalamus in the mouse.

The effects of Lilly 110141 (fluoxetine) injected IP on self-stimulation behavior triggered in the dorsal and ventral regions of the lateral hypothalamus were studied in C57BL/6 mice strain. Lilly 110140 inhibits serotonin reuptake. It depresses dorsal self-stimulation at a low dose (5 mg/kg) and improves ventral sel-stimulation at a high dose (20 mg/kg). The changes brought about by the injection of the 5 mg/kg dose support the proposed inhibitory role of serotonin on self-stimulation and also suggest that the fibers communicating with certain serotonergic neurons are localized primarily in the dorsal region of the lateral hypothalamus.

Animals↗
PubMed1980

VIP in the rat brain: evidence for a major pathway linking the amygdala and hypothalamus via the stria terminalis.

We report here on the detailed distribution of VIP-like immunoreactivity in the rat brain by a combined immunological approach using immunocytochemistry and radioimmunoassay. VIP-like immunoreactivity was widely distributed. Cell bodies and and fibres were noted principally in the cortex, hippocampus, amygdala, suprachiasmatic nucleus and brain stem. In addition dense areas of immunoreactive fibres and terminals were seen in the stria terminalis and its bed nucleus. The fibres appear to form a major VIP-containing pathway which links the amygdaloid complex with the hypothalamus. Although the functional significance of VIP in the brain is unknown, its presence in the amygdala, the hypothalamus and their linking pathway, as well as its pharmacological actions suggest that it may play a role in neuroendocrine regulation and the modulation of hypothalamic function.

Amygdala↗
PubMed1982

Release of endogenous histamine in the hypothalamus of anaesthetized cats and conscious, freely moving rabbits.

The hypothalamus of anaesthetized cats and conscious, freely moving rabbits was superfused with CSF through double-walled, push-pull cannulae and the release of endogenous histamine was determined in the superfusates by a radioenzymatic assay. In the posterior hypothalamic area of the anaesthetized cat, the rate of release of endogenous histamine varied rhythmically; phases of high rate of release appeared at 60 min cycles. The release of histamine was increased by electrical stimulation of the superfused area, as well as by hypothalamic superfusion with potassium-rich CSF. In the conscious rabbit, the anterior hypothalamic area and the posterior hypothalamic nucleus were superfused simultaneously. In both regions, the resting release of histamine varied rhythmically at approximately 70 min cycles. Phases of high or low-rate of release in the anterior hypothalamic area coincided with the corresponding phases in the posterior hypothalamic nucleus. The rhythmic release of endogenous histamine in the hypothalamus, as well as the ability of depolarizing stimuli to enhance the release of the amine support the idea that histamine acts as a neurotransmitter in the central nervous system.

Anesthesia↗
PubMed1980

Metabolism of 3H-noradrenaline released from isolated rat hypothalamus by extracts of black widow spider glands.

In the isolated rat hypothalamus preincubated with 3H-noradrenaline, an extract from the venom glands of Latrodectus mactans elicited on overflow of tritium which consisted of 70--71% 3H-noradrenaline and 18% 3H-3,4-dihydroxyphenylglycol. Exposure to cocaine or pargyline diminished the formation of 3H-3,4-dihydroxyphenylglycol, suggesting that the glycol is formed presynaptically after neuronal reuptake of the transmitter released by the venom. Our data suggest that the venom depolarizes the noradrenergic neurones of rat hypothalamus, and that the depolarization leads to calcium-dependent release of 3H-noradrenaline.

Animals↗
PubMed1978

Metabolic fate of 3H-noradrenaline released from the mouse hypothalamus.

In slices of mouse hypothalamus labelled in vitro with 3H-noradrenaline (3-H-NA), the deaminated metabolite 3H-3,4-dihydroxyphenylglycol (3H-DOPEG), represented 40.2 +/- 2.6% of the total outflow of radioactivity and was the main fraction in the spontaneous efflux. Inhibition of neuronal monoamine oxidase by exposure to 60 micron bretylium, reduced the outflow of 3H-DOPEG to 9.7 +/0 0.3%. At the same time, the proportion of 3H-normetanephrine (3H-NMN) was significantly increased. On the other hand, an increased outflow of 3H-DOPEG and a lower proportion of 3H-NMN was obtained in the presence of 2.9 micron of the reserpine like agent Ro 4-1284. It is suggested that in the mouse hypothalamus, the deaminated metabolite, DOPEG, is formed inside the nerve terminals, while the O-methylated metabolite, NMN, might result from the activity of extraneuronal catechol O-methyltransferase.

Animals↗
PubMed1978

Decreased cAMP content of the hypothalamus of genetically hypertensive rats.

In genetically hypertensive rats an altered catecholamine content of hypothalamic structures has been reported. In the present study cAMP was estimated in the hypothalamus and cortex of genetically hypertensive rats and compared with normotensive controls of the same strain. It is shown, that the cAMP content of the hypothalamus of the hypertensive animals was decreased to about 60% of control values, whereas there was no difference of the cAMP content in the cortical regions of the same animals. These results indicate an alteration of the adenyl cyclase-cAMP-phosphodiesterase system in hypothalamic structures of genetically hypertensive rats.

Animals↗
PubMed1981

Catecholamine-containing neurons in cultures of fetal rat hypothalamus: distribution, morphology, and maturation.

The distribution, morphology, and maturation of catecholamine (CA) neurons have been studied in hypothalamic explants from late-gestation rats. CA-containing neurons were identified using the glyoxylic acid technique. CA-containing processes were present from all hypothalamic areas except the preoptic region. Several fiber types were identified. CA neurons in vitro resemble CA neurons in adult hypothalamus. This tissue culture system may be useful in the study of a number of properties of hypothalamus CA neurons.

Animals↗
PubMed1992

Preproenkephalin RNA increases in the hypothalamus of rats stressed by social deprivation.

1. Pharmacological evidence indicates that stress induced by brief (14 to 20-day) social deprivation in the rat is associated with an activation of the central preproenkephalin (ENK) opioid system. This study examines the neurochemical evidence that substantiates such an activation. 2. Using a specific ENK complementary DNA probe, ENK RNA levels were measured by dot blot and Northern blot analyses in different brain areas of socially deprived rats. Immunoreactivity to met-enkephalin-derived peptides was also evaluated by radioimmunoassay in the same brain regions. 3. Brief social deprivation increased the levels of ENK RNA and enkephalin immunoreactivity in whole hypothalamus. 4. Our data suggest that this type of stress appears to be associated to an induction of ENK gene transcription in hypothalamus.

Animals↗
PubMed1990

Picomolar-affinity binding and inhibition of adenylate cyclase activity by melatonin in Syrian hamster hypothalamus.

1. The effect of melatonin on forskolin-stimulated adenylate cyclase activity was measured in homogenates of Syrian hamster hypothalamus. In addition, the saturation binding characteristics of the melatonin receptor ligand, [125I]iodomelatonin, was examined using an incubation temperature (30 degrees C) similar to that used in enzyme assays. 2. At concentrations ranging from 10 pM to 1 nM, melatonin caused a significant decrease in stimulated adenylate cyclase activity with a maximum inhibition of approximately 22%. 3. Binding experiments utilizing [125I]iodomelatonin in a range of approximately 5-80 pM indicated a single class of high-affinity sites: Kd = 55 +/- 9 pM, Bmax = 1.1 +/- 0.3 fmol/mg protein. 4. The ability of picomolar concentrations of melatonin to inhibit forskolin-stimulated adenylate cyclase activity suggests that this affect is mediated by picomolar-affinity receptor binding sites for this hormone in the hypothalamus.

1-Methyl-3-isobutylxanthine↗
PubMed1981

Subcellular distribution of coronary dilatatory protein-hormonal complexes in rat hypothalamus.

We previously reported the presence of a group of coronary dilatatory protein-carriers of the cardioactive neurohormones and precursors of bioactive compounds in the hypothalamus of some animals. Investigation of the subcellular distribution of those proteins revealed their localization in neurosecretory granules and in synaptosomes of the hypothalamus. In further investigation of the regional distribution of coronary-active proteins in different parts of the brain they were found in synaptosomes of the cerebral cortex too. The main location of coronary-active proteins in synaptosomes indicates their participation in synaptic functions.

Animals↗
PubMed1979

Uptake of para-tyramine and meta-tyramine into slices of the caudate nucleus and hypothalamus of the rat.

The kinetics of the uptake of p-tyramine, m-tyramine, and dopamine were investigated in slices of the hypothalamus and striatum of the rat in the presence of nialamide. When uptake was analyzed by a least-squares fit to a Lineweaver-Burk plot, each amine appeared to be concentrated by both a "low"-affinity and a "high"-affinity system in both brain regions. The obtained Km and Vmax values for the "high"-affinity uptake system for each amine in both brain regions were similar. In general terms, the uptake systems in the striatum exhibited larger Km and Vmax values, with the velocity of uptake being in the order dopamine less than m-tyramine less than p-tyramine. 2,4-Dinitrophenol (DNP) and ouabain reduced all uptakes in the caudate, but reduced only the "high"-affinity uptake of m-tyramine and the "low"-affinity uptake of dopamine in the hypothalamus.

Animals↗
PubMed1980

Differential effects of benztropine and desipramine on the high affinity uptake of paratyramine in slices of the caudate nucleus and hypothalamus.

The effect of benzotropine and desipramine on the uptake of dopamine and p-tyramine was studied in slices of caudate and hypothalamus. In the hypothalamus, of the various combinations of drugs and amines, desipramine inhibited p-tyramine uptake most effectively. In the caudate, benzotropine inhibited dopamine uptake most effectively. It is suggested that in the caudate, p-tyramine may possess its own unique transport system distinct from that utilized by dopamine which is inhibited by benzotropine.

Animals↗
PubMed1986

Rate of in vivo verapamil exchange within the hypothalamus of the cat as examined by push-pull perfusion.

To investigate the characteristics of the uptake within hypothalamic tissue of the Ca2+-channel blocker, verapamil, push-pull canulae were implanted bilaterally above the anterior hypothalamic-preoptic area (AH/POA) and posterior hypothalamus (PH) of the cat. The functional reactivity of these two anatomical regions was verified in the unrestrained cat, prior to a push-pull perfusion, by a micro-injection of either 5-7 micrograms norepinephrine (NE) into AH/POA, or by perfusion of 50 mM Ca2+ within the PH, both of which induce a transient decline in the cat's core temperature. Verapamil was perfused in a concentration of 0.4, 2.0 or 4.0 micrograms/microliter for successive 10 and 20 min intervals within these NE and Ca2+-sensitive sites. A quantitative analysis of verapamil in each sample of perfusate was performed double-blind by HPLC-spectrophotometric detection. The results showed that the percent recovery of verapamil after the 10 min interval was always less than that after the next 20 min period of perfusion. These recovery values were independent of the site of perfusion and the concentration of verapamil. However, the mean uptake of verapamil into tissue after 10 min was significantly greater than that after the 20 min period for all concentrations tested. These results demonstrate that the hypothalamus has a time-dependent characteristic to incorporate a Ca2+-channel blocker into the parenchyma. Once the point of tissue saturation is reached, a steady-state level of verapamil uptake is established.

Animals↗
PubMed1979

Histochemical characterization of monoamine oxidase in ependyma of rat hypothalamus.

Monoamine oxidase (MAO) activity has been demonstrated histochemically in rat hypothalamic ependyma using the sulphate-tetrazolium and coupled peroxidatic techniques with tryptamine, tyramine, 5-hydroxytryptamine and benzylamine as substrates. Both methods were applied to cryostat sections with and without exposure to selective amine oxidase inhibitors, including the selective A-MAO inhibitor clorgyline, and the B-MAO inhibitor deprenyl. Our results show that both cuboidal-columnar and tanycyte ependyma contain one or more forms of MAO not generally present in the hypothalamus. It is suggested that ependymal MAO may form an amine-barrier system modulating the movement and effect within the hypothalamus of specific cerebrospinal fluid or blood monoamines.

Animals↗
PubMed1989

Somatostatin concentration and binding in the rat hypothalamus and striatum during severe insulin-induced hypoglycemia.

Hypoglycemia was induced by administration of insulin (40 I.U./kg) to 24 h fasted rats. Somatostatin-like immunoreactivity (SLI) and 125I-Tyr11-somatostatin binding were measured in the striatum and hypothalamus at the onset of hypoglycemic coma (5-10 min). No significant changes in SLI concentration were detected in either site although the total number of specific somatostatin receptors in the striatum membranes, but not in the hypothalamus, decreased in insulin-injected rats when compared with the control group.

Animals↗