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In vivo dialysis measurements of dopamine and serotonin release in the nucleus accumbens as a function of body weight
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ABSTRACTS
The NK-3 Receptor Subtype Mediates Central Evoked by Tachykinins. C. POLIDORI, M. MASSI, G. COSTA and G. Camerino, Italy.
DE
Vasopressin
Release
M. PERFUMI, A. SAJIA, CARO. Institute of Pharmacology, University of Camerino, 62032
Intracerebroventricular (i.c.v.) injection of eledoisin (ELE) evokes vasopressin (VP) release in the rat. The present study evaluated the tachykinin (TK) receptor subtype involved in the effect. Testing of several natural and synthetic TKs, including selective agonists for different TK receptors, showed that only those endowed with high activity at NK-3 receptors are able to evoke VP release. The effect is of central origin and not due to hypotension evoked by leakage of I.C.V. TKs, which are potent vasodilators, into the periphery. The magnocellular part of the paraventricular nucleus, which is one of the richest brain areas in NK-3 receptors, might be the site of action for this central effect of TKs.
Sensitivity of Spontaneously Hypertensive Rats to the Antidipsic Effect of Eledoisin. P. L. POMPEI, M. MASSI, G. DE CAR0 and M. PERFUMI. Institute of Pharmacology, University of Camerino, 62032 Camerino, Italy. The present study investigated the sensitivity of spontaneously hypertensive (SH) and of Wistar Kyoto (WK) rats to the antidipsic effect of intracerebroventricular (i.c.v.) injection of eledoisin (ELE). Drinking has been induced by i.c.v. angiotensin II (long/rat), by subcutaneous (s.c.) hypertonic NaCl (15 M, 1 ml/lCOg body weight) and by 18 h of water deprivation. SH rats have been proved to be less sensitive than WK rats to the inhibitory effect of ELE, on angiotensininduced drinking and on osmotic drinking, while no difference was detected for the effect of ELE on drinking induced by water deprivation. The different sensitivity of SH and WK rats might be related to different functional regulation of central tachykinergic mechanisms.
In vivo Dialysis Measurements of Dopamine and Serotonin Release in the Nucleus Accumbens as a Function of Body Weight. E. POTHOS, G. P. MARK, L. HERNANDEZ and B. G. HOEBEL. University, Princeton, NJ 08544, U.S.A.
Department
of Psychology,
Princeton
Extracellular DA increases in the nucleus accumbens during feeding and water intake in response to deprivation. In the present study, the use of in viuo microdialysis with HPLC-EC at 60min intervals showed that mean basal extracellular DA decreased in rats reduced to 80% body weight. There was no detectable change in 5-HT levels. DOPAC decreased in the 80% body weight animals, while SHIAA and HVA remained at baseline levels. The results suggest that the mesolimbic DA system is sensitive to alterations in body weight.
Major Gene Involvement in Human Obesity. R. ARLEN PRICE, ROBERTA NESS and PETER LASKARZEWSKI. University of Pennsylvania, PA, U.S.A., Columbia University, NY, U.S.A. and University of Cincinnati, U.S.A. Obesity is influenced by polygenic inheritance (many genes with small effects) and by major genes (a few genes with large effects on those who possess them). We have just completed a study of 965 families that suggests that major genes which predispose to obesity are common. Major gene influence appears to be especially likely for obesity that exceeds 40% or more over ideal weight. The development and clinical expression of obesity is heterogeneous, and its seems likely that several genes are involved. Our findings make it possible to begin molecular genetic studies aimed at isolating individual genes that influence obesity.
ABSTRACTS
The NK-3 Receptor Subtype Mediates Central Evoked by Tachykinins. C. POLIDORI, M. MASSI, G. COSTA and G. Camerino, Italy.
DE
Vasopressin
Release
M. PERFUMI, A. SAJIA, CARO. Institute of Pharmacology, University of Camerino, 62032
Intracerebroventricular (i.c.v.) injection of eledoisin (ELE) evokes vasopressin (VP) release in the rat. The present study evaluated the tachykinin (TK) receptor subtype involved in the effect. Testing of several natural and synthetic TKs, including selective agonists for different TK receptors, showed that only those endowed with high activity at NK-3 receptors are able to evoke VP release. The effect is of central origin and not due to hypotension evoked by leakage of I.C.V. TKs, which are potent vasodilators, into the periphery. The magnocellular part of the paraventricular nucleus, which is one of the richest brain areas in NK-3 receptors, might be the site of action for this central effect of TKs.
Sensitivity of Spontaneously Hypertensive Rats to the Antidipsic Effect of Eledoisin. P. L. POMPEI, M. MASSI, G. DE CAR0 and M. PERFUMI. Institute of Pharmacology, University of Camerino, 62032 Camerino, Italy. The present study investigated the sensitivity of spontaneously hypertensive (SH) and of Wistar Kyoto (WK) rats to the antidipsic effect of intracerebroventricular (i.c.v.) injection of eledoisin (ELE). Drinking has been induced by i.c.v. angiotensin II (long/rat), by subcutaneous (s.c.) hypertonic NaCl (15 M, 1 ml/lCOg body weight) and by 18 h of water deprivation. SH rats have been proved to be less sensitive than WK rats to the inhibitory effect of ELE, on angiotensininduced drinking and on osmotic drinking, while no difference was detected for the effect of ELE on drinking induced by water deprivation. The different sensitivity of SH and WK rats might be related to different functional regulation of central tachykinergic mechanisms.
In vivo Dialysis Measurements of Dopamine and Serotonin Release in the Nucleus Accumbens as a Function of Body Weight. E. POTHOS, G. P. MARK, L. HERNANDEZ and B. G. HOEBEL. University, Princeton, NJ 08544, U.S.A.
Department
of Psychology,
Princeton
Extracellular DA increases in the nucleus accumbens during feeding and water intake in response to deprivation. In the present study, the use of in viuo microdialysis with HPLC-EC at 60min intervals showed that mean basal extracellular DA decreased in rats reduced to 80% body weight. There was no detectable change in 5-HT levels. DOPAC decreased in the 80% body weight animals, while SHIAA and HVA remained at baseline levels. The results suggest that the mesolimbic DA system is sensitive to alterations in body weight.
Major Gene Involvement in Human Obesity. R. ARLEN PRICE, ROBERTA NESS and PETER LASKARZEWSKI. University of Pennsylvania, PA, U.S.A., Columbia University, NY, U.S.A. and University of Cincinnati, U.S.A. Obesity is influenced by polygenic inheritance (many genes with small effects) and by major genes (a few genes with large effects on those who possess them). We have just completed a study of 965 families that suggests that major genes which predispose to obesity are common. Major gene influence appears to be especially likely for obesity that exceeds 40% or more over ideal weight. The development and clinical expression of obesity is heterogeneous, and its seems likely that several genes are involved. Our findings make it possible to begin molecular genetic studies aimed at isolating individual genes that influence obesity.