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Biomedical subjects

M Palkovits

Publications and source records attributed to M Palkovits.

At least 361 records · Page 20Linked to original sources
PubMed1977

The effect of hypothalamic deafferentation on somatostatin-like activity in the rat brain.

Somatostatin-like activity (SLA) was determined by radioimmunoassay in several brain regions of animals which had either undergone complete deafferentation of the medial basal hypothalamus or a sham-operation. Surgical isolation of the medial basal hypothalamus caused this region to lose most of its SLA, but did not affect activity elsewhere. Similarly, partial (frontal) deafferentation of the medial basal hypothalamus resulted in a substantial decrease in SLA there.

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PubMed1977

Ascending projections to the hypothalamus and limbic nuclei from the dorsolateral pontine tegmentum: a biochemical and electron microscopic study.

Axons arising from the dorsolateral pontine tegmentum of the rat were traced in various hypothalamic and limbic nuclei by the electron microscopic degeneration method (0.5-8 day survival times) and by measuring regional norepinephrine (NE) concentrations after 12 days of survival using a radioenzymatic method. Significant reductions (41-85%) in NE contents were observed in the supraoptic, arcuate, basal and lateral amygdaloid nuclei and in the hippocampus 12 days after the bilateral electrolytic lesions of the locus coeruleus. No changes in NE concentrations were observed in the ventromedial, septal, central amygdaloid nuclei, in the median eminence and olfactory tubercle. Parabrachial lesions resulted in a decrease of NE content only in the olfactory tubercle. By means of electron microscopy terminal degeneration was found in the hypothalamic paraventricular, dorsomedial nuclei, in the median eminence, in the bed nucleus of the stria terminalis, in the central, lateral and basal amygdaloid nuclei, in the hippocampus and in the anterior ventral thalamic nucleus.

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PubMed1977

Blood supply of the rat hypothalamus. V. The medial hypothalamus (nucleus ventromedialis, nucleus dorsomedialis, nucleus perifornicalis).

Using the India ink double-perfusion technique, the blood vessels of the rat's medial hypothalamus were reconstructed from serial sections. The area studied comprised the ventromedial, dorsomedial and perifornical nuclei. The arterial supply of this territory comes from the middle hypothalamic and the anterior, middle and posterior tuberal arteries. The drainage is strictly undirectional: ventralward by the anterior, middle and posterior ventromedial, the posteromedial and posterolateral hypothalamic veins, all ending in the basal vein. The arteries of the ventromedial and dorsomedial nuclei are distinct from those of the arcuate nucleus and median eminence, and their drainage is not connected with the portal vessels. The nuclei studied, even at the levels of their subdivisions, possess own arteries whose territories of supply can well be distinguished with a minimum of overlap. The topography of these arteries is described in detail. The medial hypothalamus has no vascular connections with other regions of the diencephalon including the thalamus.

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PubMed1976

Effect of surgical isolation of the hypothalamus on its neurotransmitter content.

The concentrations of norepinephrine, dopamine-beta-hydroxylase, dopamine, tyrosine hydroxylase, phenylethanolamine-N-methyltransferase, serotonin, tryptophan hydroxylase, histamine, glutamic acid decarboxylase, and choline acetyltransferase were determined in selected hypothalamic nuclei and in the median eminence after deafferentation of the medial basal hypothalamus. Norepinephrine and dopamine-beta-hydroxylase fell markedly while dopamine and tyrosine hydroxylase did not. Serotonin also decreased in all regions studied; histamine decreased in none. Choline acetyltransferase, phenylethanolamine-N-methyltransferase, and glutamic acid decarboxylase declined in some areas, but not in others.

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PubMed1976

Regional distribution of substance P in the brain of the rat.

Using a sensitive radioimmunoassay we have studied the regional distribution of substance P. The level of substance P is higher in the mesencephalon, hypothalamus and preoptic area than in other regions of the brain. Substance P is found in especially high concentrations in the reticular part of the substantia nigra and the interpeduncular nucleus. It is present in large amounts in several septal, preoptic and hypothalamic nuclei as well.

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PubMed1976

Regional concentrations of noradrenaline and dopamine in rat brain.

The concentrations of noradrenaline and lopamine of 92 brain regions have been measured by a radiometric method which enabled discrimination between noradrenaline and adrenaline. Almost all brain regions investigated contained both noradrenaline and lopamine in measurable amount. However, both catecholamines appeared to be unevenly distributed. Very high dopamine concentrations were measured in the olfactory tubercle, the nucleus accumbens, the caudate nucleus and the rostral part of the medial forebrain bundle; the globus pallidus, the nucleus tractus diagonalis and the nucleus septalis lateralis were also very rich in dopamine. Outside the telencephalon the dopamine concentrations were rather low, except in the median eminence and the area tegmentalis ventralis (Tsai), an area corresponding to the A10 region. High noradrenaline concentrations were measured in most hypothalamic nuclei. Relatively high concentrations of this catecholamine were also measured in several mesencephalic (the ventral part of the central gray, the nucleus raphe dorsalis and the nucleus cuneiformis) and pontine (the locus coeruleus and the nuclei parabrachiales) regions. The highest noradrenaline concentrations in the medulla oblongata were observed in the A2 region and the nucleus commissuralis, which contained at least twice as much noradrenaline as did the more rostral part of the nucleus tractus solitarii.

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PubMed1976

The projections of the A8, A9 and A10 dopaminergic cell bodies: evidence for a nigral-hypothalamic-median eminence dopaminergic pathway.

Using the microdissection method of Palkovits and a sensitive microassay for dopamine (DA) and norepinephrine (NE), the CNS projections of the nigral A8, A9 and A10 dopaminergic cell bodies have been determined in rat brain. Following bilateral electrolytic lesions of the A8-A9-A10 region, DA levels fell significantly in the following areas: dorsal septal nucleus (85%), olfactory tubercle (75%), lateral amygdaloid nucleus (75%), habenula (75%), parietal cortex (75%), cingulate cortex (70%), cerebellum (50%), thalamic paraventricular nucleus (50%), and preoptic suprachiasmatic nucleus (45%). Of particular interest was the finding of a 40% fall in the dopamine levels of the median eminence after such lesions. Concentrations of NE in these same areas following lesions of the A8-A9-A10 region were unchanged. These findings suggest that the nigral A8, A9 and A10 dopaminergic cell bodies, project diffusely to many different areas of cortex, hypothalamus, and brain stem, and, more importantly, provide evidence for a previously unsuspected dopaminergic pathway from substantia nigra to median eminence, an area intimately concerned with neuroendocrine regulation.

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PubMed1976

Distribution of glutamate decarboxylase in discrete brain nuclei.

The L-glutamate decarboxylase (GAD) levels of 70 rat brain nuclei were determined. The distribution of GAD is uneven. High AAD activity was found in the substantia nigra, the colliculi, some hypothalamic nuclei (e.g. dorsomedial) some nuclei of the limbic system (e.g. tractus diagonalis and accumbens) and the medial forebrain bundle. The reticular part of the substantia nigra had the highest activity, two-fold higher than any other nucleus. Low GAD activity was found in the nuclei of the pons, the hypothalamic median eminence and the reticular formation. Moderate activity was measured in most areas studied. The biochemical mapping of GAD is discussed in relation to possible GABA pathways in the brain.

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