Pacifico Valeri

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In the present study, we investigated the role of vasopressin in the development of quinpirole-induced hyperdipsia in the rat. We report that: (1), an acute intraperitoneal (i.p.) injection of 0.56 mg/kg of quinpirole increased plasma vasopressin (radioimmunoassay) at 15 min but not at 30 or 120 min; (2), nine daily injections of quinpirole (0.56 mg/kg,(More)
Specific [(3)H]corticosterone uptake in hippocampus and septum was reduced in socially deprived, as well as in crowding-stressed mice, in comparison with grouped ones. Its magnitude was related to hierarchic rank in the group but unrelated to agressiveness which, in turn, was unaffected by adrenalectomy and corticosterone replacement. A complex, regulatory(More)
Acetylcholine muscarinic receptors are a family of five G-protein-coupled receptors widely distributed in the central nervous system and in peripheral organs. Activation of certain subtypes of muscarinic receptors (M1, M3, M5) has been found to modulate DNA synthesis in a number of cell types. In several cell types acetylcholine, by activating endogenous or(More)
Guinea-pig ileum stored for 30 min in Krebs solution and then mounted in Tyrode solution gave reproducible contracture responses to naloxone after brief exposure to morphine. The preparation lasted for several hours and a variety of pharmacological tests could be made. Clonidine, an alpha 2-adrenoceptor agonist, and nifedipine, a calcium channel antagonist,(More)
In a previous study, we found that the kappa opioid agonist U50,488H (U50) suppresses both appetitive and consummatory components of drinking behavior in rats trained to negotiate water in a straight runway. U50 also activates diuresis. Kappa opioid mechanisms could therefore play a dissipative role in the body's water balance. Since naloxone inhibits(More)
Trazodone and dapiprazole displace ligands binding to rat brain alpha-1 adrenoceptors. The displacement of 3H-ligands to alpha-2, serotonin1 (5-HT1), dopamine, beta and opiate receptors is either absent or takes place at relatively higher concentrations. Trazodone, unlike dapiprazole, also inhibits binding to serotonin2 (5-HT2) receptors. Some(More)
The multiple cascades of signal transduction pathways that lead from receptors on the cell membrane to the nucleus, thus translating extracellular signals into changes in gene expression, may represent important targets for neurotoxic compounds. Among the biochemical steps and pathways that have been investigated are the metabolism of cyclic nucleotides,(More)
There is evidence that central noradrenergic hyperactivity is involved in the manifestation of the major signs and symptoms of the opiate withdrawal syndrome. In order to assess whether or not the noradrenergic system is also implicated in the development of opiate dependence, we studied dapiprazole, an alpha-1 selective adrenoceptor antagonist, clonidine(More)
Chronic amphetamine administration has been found to produce diuresis and polydipsia in rats. We have found that dapiprazole acutely suppresses the diuretic, but not the ingestive, effects of amphetamine. To see whether diuresis is the physiological stimulus driving amphetamine-mediated polydipsia, we injected rats daily with d,l-amphetamine and the alpha-1(More)
Naloxone, added after contractions induced by CCK-8 on the guinea pig ileum preparation, elicited a contraction attributed to the release of endogenous opioid which could inhibit the excitatory action of the peptide. With large concentrations of CCK-8, the preparation gave reproducible responses with time. Naloxone, added before the peptide, protracted the(More)