niravoline and mozavaptan

Topics: Animals; Anti-Bacterial Agents; Antidiuretic Hormone Receptor Antagonists; Benzazepines; Benzeneacetamides; Body Water; Demeclocycline; Diabetes Insipidus; Dogs; Humans; Kidney; Liver Cirrhosis; Liver Cirrhosis, Experimental; Loop of Henle; Pyrrolidines; Rats; Receptors, Opioid; Vasopressins; Water-Electrolyte Balance

kappa-Opioid receptor agonists (niravoline) or nonpeptide antidiuretic hormone (ADH) V2 receptor antagonists (OPC-31260) possess aquaretic activity in cirrhosis; however, there is no information concerning the effects induced by the chronic administration of these drugs under this condition. To compare the renal and hormonal effects induced by the long-term oral administration of niravoline, OPC-31260, or vehicle, urine volume, urinary osmolality, sodium excretion, and urinary excretion of aldosterone (ALD) and ADH were measured in basal conditions and for 10 days after the daily oral administration of niravoline, OPC-31260, or vehicle to cirrhotic rats with ascites and water retention. Creatinine clearance, serum osmolality, ADH mRNA expression, and systemic hemodynamics were also measured at the end of the study. Niravoline increased water excretion, peripheral resistance, serum osmolality, and sodium excretion and reduced creatinine clearance, ALD and ADH excretion, and mRNA expression of ADH. OPC-31260 also increased water metabolism and sodium excretion and reduced urinary ALD, although the aquaretic effect was only evident during the first 2 days, and no effects on serum osmolality, renal filtration, and systemic hemodynamics were observed. Therefore, both agents have aquaretic efficacy, but the beneficial therapeutic effects of the long-term oral administration of niravoline are more consistent than those of OPC-31260 in cirrhotic rats with ascites and water retention.

Topics: Aldosterone; Animals; Antidiuretic Hormone Receptor Antagonists; Benzazepines; Benzeneacetamides; Body Water; Body Weight; Carbon Tetrachloride Poisoning; Diuretics; Hemodynamics; Hormones; Hypothalamus; Kidney; Liver Cirrhosis, Experimental; Male; Osmolar Concentration; Pyrrolidines; Rats; Rats, Wistar; Receptors, Opioid, kappa; RNA, Messenger; Urodynamics; Vasopressins

Strategies for developing selective water diuretic agents have involved development of kappa opioid receptor agonists and vasopressin V2 receptor antagonists; however, these two classes of compounds have not been compared directly. We have investigated the activity of three kappa receptor agonists and one nonpeptide vasopressin receptor antagonist in conscious dogs. SB 215520, SB 215519 and niravoline are selective kappa agonists with variable abilities to cause a water diuresis and ataxia in rats. When administered to conscious hydropenic dogs, the kappa agonists resulted in an increase in free water clearance; however, these effects were associated with an antinatriuresis, an increase in heart rate and, at the higher doses, central nervous system side effects. Conversely, the vasopressin receptor antagonist, OPC 31260, resulted in a significant water diuresis without any accompanying changes in sodium excretion and heart rate, and with no apparent central nervous system effects. These studies suggest that, at least in dogs, a vasopressin receptor antagonist is a more selective water diuretic than a kappa receptor agonist.

Topics: Animals; Antidiuretic Hormone Receptor Antagonists; Benzazepines; Benzeneacetamides; Diuresis; Dogs; Female; Male; Piperidines; Pyrrolidines; Rats; Rats, Sprague-Dawley; Receptors, Opioid, kappa; Water