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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)
1. This study was undertaken to investigate whether, after a brief exposure of guinea-pig isolated ileum and rabbit jejunum to bremazocine, a kappa-opioid agonist also possessing antagonist activity at mu-opioid receptors, the addition of opioid antagonists produced withdrawal contractures. Our aim was to verify in these tissues the existence of an(More)
Time-courses of both 'total' (unchanged plus metabolized) and unmetabolized acetaminophen were investigated in plasma and ocular tissues of rabbit after intravenous administration. The drug freely diffuses across the haemato-ocular barriers, reaching eye levels equal to those in the plasma; ocular concentrations are higher than those of all other(More)
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)
1. One reason why rabbit jejunum is suitable for studying the mechanisms underlying the actions of the various neurotransmitters and their interactions is its spontaneous motility. The main regulator of spontaneous motility is the cholinergic system. How the cholinergic system regulates the spontaneous activity in the rabbit jejunum and how it affects the(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)
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)
Carnitine plays an important role in the metabolism of fatty acids. Its presence is considerable in tissues that use fatty acids as an important source of energy, such as the heart and skeletal muscle. Free carnitine and acid soluble acylcarnitines are present in various tissues of the rabbit eye. The lowest concentration of carnitine was observed in the(More)
The time courses of aspirin and salicylate in plasma and ocular tissues of rabbits were investigated after the i.v. administration of aspirin. Unhydrolyzed aspirin rapidly disappears from plasma and many ocular compartments but persists up to 4 hours in aqueous and vitreous humours. Salicylate decreases in plasma follow an exponential kinetics; in aqueous(More)