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Biomedical subjects

V Roşca

Publications and source records attributed to V Roşca.

At least 19 recordsLinked to original sources
PubMed1986

Evidence for the involvement of cerebral renin-angiotensin system (RAS) in stress analgesia.

Studies concerning variations of the central renin-angiotensin system (RAS) during immobilization stress in rats have shown a significant increase in renin-like activity in the hypothalamus and fronto-parietal cortex, together with a definite decrease in the hypophysis and pineal gland. The resultant stress analgesia is blocked by the previous administration of naloxone and saralasin (angiotensin II antagonist). The intracerebral administration of renin and angiotensin II produces an increase in latencies to thermoalgesic stimuli; this is reduced, as is immobilization stress, by naloxone and saralasin. Both chemical hypophysectomy obtained by dexamethasone pretreatment as well as surgical epiphysectomy block the stress-induced analgesia. The experimental data obtained argue in favour of the participation of the cerebral RAS in stress analgesia through the indirect mechanism of release of opioid peptides.

Analgesia↗
PubMed1981

Possible hormonal role of the angiotensin-like peptides in mammals' pineal gland.

An isorenin is synthetized in the pineal gland cells. The amount of isorenin as well as the synthesis of angiotensin I and II in the pineal gland depends on the circadian rhythm, osmotic stimuli and stimulation of the cervical sympathetic postganglionar fibres. Pineal angiotensin is released both into the blood and in the cerebrospinal fluid (CFS). The major site of the pineal angiotensin action are the circumventricular organs, the preiventricular receptors of the anterior hypothalamus and the epiphysis cerebri itself. Except its participation in regulating arterial pressure and the hydroelectrolytic metabolism, through its central effects on the brain, pineal angiotensin-like peptides also participate in the pool of circulating angiotensin and it may represent Farrell's pineal glomerulotropic factor.

Angiotensin I↗
PubMed1980

Influence of angiotensin II on dog pineal serotonin content.

Intravenous infusion of angiotensin II in different concentrations for 2 h induced an increase in the serotonin contents of pineal gland, hypothalamus and brain stem in dogs. The maximal stimulatory effect was obtained with a concentration of 50 ng angiotensin II/kg body wt./min. Results are interpreted with regard to the concept of an intrinsic isorenin-angiotensin system and its implications at the level of brain nervous tissue and accessory glands. Experimental data indicating the possible existence of positive and negative feedback relationships between the brain isorenin-angiotensin system and serotonin metabolism in the pineal gland, are presented.

Angiotensin II↗
PubMed1978

Iso-renin secretion from rat brain cortex slices in vitro under the influence of ions and electrical stimulation.

The aim of this study was to obtain additional data concerning the influence of changes in osmolarity and ionic composition on iso-renin secretion from rat brain cortex slices. The slices were isolated and superfused in vitro according to the technique of Pull and McIlwain (1972). The secretion of iso-renin was strongly stimulated by an increase of Na+ concentration. Iso-renin output almost doubled upon raising NaCl from 120 to 240 mM. Decrease of the NaCl concentration to 60 mM resulted in a reduced iso renin secretion while addition of tetrodotoxin (TTX) (60 micron) did not significantly alter the iso-renin content of brain slices. Changes in osmotic pressure were without significant influence. Electrical stimulation or elevation of extracellular K+ concentrations enhanced iso-renin secretion. Furthermore, Ca2+ ions seem to increase both the content and the release of cerebral iso-renin.

Animals↗
PubMed1975

A renin-like activity in pineal gland and hypophysis.

Using Boucher micromethod for determining renin activity in the rat pineal gland and hypophysis tissues, before and after NaCl 10% i.v. administration, the normal rats showed an average value of 96.8 +/- 21 ng Ang/g/h at the hypophysis level, and 325 +/- 66 ng Ang/g/h in epiphysis. In rats previously treated with 1--1.5 ml. NaCl 10% i.v., a more reduced renin-like activity was found both in hypophysis and epiphysis, that is 36.5 +/- 13 ng Ang/g/h and 144.5 +/- 38 Ang/g/h, respectively. In keeping with the previous data regarding the drinking and ADH-releasing effects of angiotensin, the obtained results plead for a possible participation of the cerebral glandular tissue renin in the self-regulating of the hydroelectrolytic balance.

Animals↗