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M Palkovits

Publications and source records attributed to M Palkovits.

At least 325 records · Page 18Linked to original sources
PubMed1980

Adrenergic innervation of the rat hypothalamus.

The adrenergic innervation of the hypothalamus was studied by measuring hypothalamic adrenaline levels following surgical transection of the lower brain stem or electrolytic lesion of the medullary adrenaline-containing cell groups. The adrenaline levels in some hypothalamic nuclei and in the median eminence showed a slight decrease after partial transection of the medulla oblongata, whilst there was a pronounced decrease (by 59-78%) 7-10 days following total hemisection or unilateral lesion of the C1-catecholaminergic cell group in the medulla oblongata.

Animals↗
PubMed1980

Topography of chemically identified neurons in the central nervous system: progress in 1977-1979.

The latest results concerning the chemically identified central nervous system (CNS) neurons are summarized. Only those observations proved by morphological or biochemical methods in individual regions are utilized. During the last decade the presence and topography of almost 40 substances have been identified in the CNS. This review aims to demonstrate progress during 1977--1979. The coexistence of more and more biogenic amines, acetylcholine, amino acids and neuropeptides within the same CNS regions or nuclei has become evident. Although many neurons are already chemically characterized, the nature of most CNS cells is still unknown.

Acetylcholine↗
PubMed1979

Dopamine, noradrenaline and 3,4-dihydroxyphenylacetic acid (DOPAC) levels of individual brain nuclei, effects of haloperidol and pargyline.

Noradrenaline (NA), dopamine (DA) and DOPAC were determined with a newly developed radioenzymatic method simultaneously in the striatum, limbic system, hypothalamus and in catecholamine-containing cell groups of the rat brain. Only a loose relationship could be established between DOPAC and DA contents in the various brain areas. The lowest relative DOPAC level (DOPAC/DA ratio) was found in the median emience, while it was the highest in the periventricular nucleus of the hypothalamus. Haloperidol increased the DOPAC level in only part of the nuclei examined (striatum, olfactory tubercle, central amygdaloid nucleus), while in other limbic regions as well as in the hypothalamic dorsomedial, arcuate and paraventricular nuclei it proved to be ineffective. The DOPAC level in the locus coeruleus was decreased by haloperidol. Pargyline caused an appr. 50% decrease of DOPAC content of most of the nuclei in 10 min; the effectivity of the drug did not show parallelism with that of haloperidol. The monoamine oxidase inhibition caused no change in the DOPAC level in the hypothalamic periventricular and paraventricular nuclei. Results are discussed as a consequence of different reactivity of various DA-ergic terminals and catecholamine cell bodies to haloperidol and pargyline.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1979

Changes in corticotrophin releasing factor of the stalk median eminence in rats with various cuts around the medial basal hypothalamus.

The activity of corticotrophin releasing factor (CRF) in extracts of the stalk median eminence (SME) complex proper (average protein content, 30.6 micrograms) of male rats was assayed by monolayer cultures of anterior pituitary cells using the release of immunoreactive ACTH. Extracts which were equivalent to 0.025 SME of control rats usually had detectable CRF activity, while there was no detectable activity in extracts of 0.4 SME equiv. taken 8 days after complete surgical isolation of the medial basal hypothalamus (MBH). The activity of CRF in extracts from rats with an anterolateral cut around the MBH was at least ten times less than that in the control rats. One day after placing an anterolateral cut around the MBH the ACTH releasing activity of the SME was not significantly different from that of the control animals but activity decreased significantly 3 days after the operation and was at least ten times less than in the control animals on day 7 after the operation. It is suggested that most of the CRF activity of the SME is contained in nerve fibres entering the neurohaemal region from outside the MBH and that transection of these fibres produced the fall in CRF content of the SME in rats with partial or total surgical isolation of the MBH.

Animals↗
PubMed1979

Blood supply of the rat hypothalamus. VI. Posterior region of the hypothalamus (nucleus hypothalamicus posterior, nuclei praemammillares, nucleus supramammilaris, mammilary body).

It was shown by the double ink-filling technique that the arteries of the rat premammillary region and mammillary body arise from the a. communicans posterior while these areas are drained by the anterior interpeduncular vein. Disregarding some minor overlaps and anastomoses, the blood supplies of the two territories are independent of each other and from the neighbouring areas of the hypothalamus, diencephalon and mesencephalon. Arteries of the premammillary region arise from the premammillary artery, except for some branches of the posterior tuberal and interpeduncular arteries. The mammillary body is supplied by three mammillary arteries (anterior, posterior and lateral). The premammillary region drains into the anterior and posterior premammillary veins. Venous blood of the mammillary body is collected by the anterior and posterior mammillary veins which end in the anterior interpeduncular vein. The circulation of individual premammillary and mammillary nuclei is described in detail.

Animals↗
PubMed1979

Light and electron microscopic studies on the medial forebrain bundle in the rat. I. Nerve terminals in the lateral hypothalamus of extrahypothalamic origin.

Degenerated nerve terminals were demonstrated in the lateral hypothalamus of the rat following transection of the rostral and caudal fibres to the medial forebrain bundle (MFB) and a parasagittal cut along the lateral edge of the hypothalamus. In the light of these findings the termination of extrahypothalamic MFB pathways on intrinsic neurons is assumed.

Animals↗
PubMed1979

Light and electron microscopic studies on the medial forebrain bundle in the rat. ii. nerve terminals from the medial hypothalamus.

After the surgical interruption of connections between the medial and lateral hypothalamus of the rat axonal (transient) and nerve terminal degeneration was shown in the medial forebrain bundle (MFB) with light and electron microscopy. Following 1 mm long parasagittal cuts at various rostro-caudal levels the degeneration pattern within the MFB indicated a certain territoral arrangement of terminating fibres from the medial hypothalamus. After a parasagittal cut through the lateral retrochiasmatic area, degeneration was observed in the full length of the MFB. This suggests that a number of axons connect the medial and lateral hypothalamus through this area. With the aid of a parasagittal cut separating totally the medial and lateral hypothalamus, the degeneration of dendrites in the middle portion of the lateral hypothalamus was also revealed. These proved to derive from cells of the ventromedial nucleus.

Animals↗
PubMed1978

Regional distribution of muscarinic cholinergic receptors in rat brain.

Using the tritiated ligand [3H]quinuclidinyl benzilate ([3H]QNB), a specific muscarinic cholinergic antagonist, the distribution of muscarinic receptors was determined in 75 specific brain regions and nuclei removed by microdissection as well as in large brain areas. [3H]QNB binding was highest in the caudate-putamen; other regions with high binding included the nucleus accumbens, cerebral cortex and hippocampus, certain limbic and thalamic nuclei, superior colliculus, pontine nuclei and the hypoglossal nucleus. Muscarinic cholinergic receptors may be concentrated in these regions. [3H]QNB binding generally correlated well with acetylcholinesterase staining in terminals and is consistent with certain sites as particularly enriched in cholinergic synapses.

Animals↗
PubMed1978

ACTH release after tuberal electrical stimulation in rats with various cuts around the medial basal hypothalamus.

After the combined treatment with dexamethasone, morphine and pentobarbitone, the electrical stimulation in the rat tuber cinereum induces a rise in plasma corticosterone (CS) level, probably by direct stimulation of the corticoliberin-producing neural elements and the consecutive ACTH release. We have attempted to locate these corticoliberin-containing neural elements by electrical stimulation in rats with various surgical cuts (deafferentations) around the medial basal hypothalamus (MBH). Seven to eight days after the complete circumsection of the MBH, the electrical stimulation of the isolated region did not affect plasma CS level. Also, the electrical excitation proved to be ineffective after antero-lateral or only lateral sections that interrupted the fibers running through the lateral region of the retrochiasmatic area. In contrast, a rise in CS level followed electrical stimulation of rats with anterolateral transections, provided the basal part of the lateral retrochiasmatic area stayed intact. We suggest that fibers traversing the basal region of the lateral retrochiasmatic area have a major role in the release of corticoliberin from the median eminence (ME).

Adrenocorticotropic Hormone↗
PubMed1978

Basal levels of pituitary ACTH and plasma corticosterone after complete or frontal cuts around medial basal hypothalamus.

Plasma corticosterone level and corticotropin (ACTH) content of the anterior pituitary (AP) were measured after various cuts around the medial basal hypothalamus (MBH). Seven to eight days after placing a complete cut around MBH there was no change in plasma corticosterone or ACTH content of AP; the slight rise in ACTH concentration was offset by the decreased weight of AP. Twenty eight days after a frontal cut there was no change in plasma corticosterone and in bioactive or immunoreactive ACTH concentration of AP.

Adrenocorticotropic Hormone↗
PubMed1978

Neurochemical anatomy of the neuroendocrine hypothalamus. Neurochemical anatomy of the hypothalamus.

Microdissection techniques for isolated removal of the various regions of the hypothalamus as well as the individual hypothalamic nuclei are detailed. Recent development of biochemical microassays have made it possible that the concentrations of neurohormones, neuropeptides, neurotransmitters and their related enzymes could be detected in such a small volume of brain tissue than the hypothalamic nuclei. Data available of the hypothalamic distribution of above substances are summarized. The possible role and origin of intra- and extrahypothalamic neurohormones as well as the existence of the so-called "hypophysiotrophic area" are discussed.

Animals↗