Antagonistic effects of atipamezole and yohimbine on xylazine-induced diuresis in healthy dogs

• Published in: Journal of Veterinary Medical Science Vol. 71; no. 5; pp. 539 - 548
• Main Authors: Talukder, Md.h.(Tottori Univ. (Japan). Faculty of Agriculture), Hikasa, Y, Matsuu, A, Kawamura, H
• Format: Journal Article
• Language: English
• Published: Japan JAPANESE SOCIETY OF VETERINARY SCIENCE 01.05.2009; Japan Science and Technology Agency
• Subjects: Adrenergic alpha-Antagonists - pharmacology; Animals; ANTAGONISM; ANTAGONISME; ANTAGONISMO; arginine vasopressin; Arginine Vasopressin - blood; Arginine Vasopressin - urine; atipamezole; Atrial Natriuretic Factor - blood; Atrial Natriuretic Factor - urine; atrial natriuretic peptide; CHIEN; Chlorides - urine; Creatinine - urine; diuresis; Diuresis - drug effects; DOGS; Dogs - blood; Dogs - physiology; Dogs - urine; Drug Interactions; DRUGS; HORMONE RECEPTORS; Imidazoles - antagonists & inhibitors; Imidazoles - pharmacology; Male; MEDICAMENT; MEDICAMENTOS; MICTION; ORINACION; PERRO; Potassium - urine; Random Allocation; RECEPTEUR D'HORMONE; RECEPTORES DE HORMONAS; Sodium - urine; URINATION; VASOPRESINA; VASOPRESSIN; VASOPRESSINE; XILAZINA; XYLAZINE; Xylazine - pharmacology; Yohimbine - pharmacology; α2-adrenoceptor agonist and antagonists
• ISSN: 0916-7250; 1347-7439
• DOI: 10.1292/jvms.71.539

The aim of this study was to investigate and compare the antagonistic effects of atipamezole and yohimbine on xylazine-induced diuresis in healthy dogs. Five healthy male beagles were assigned to each of the 8 treatment groups in a randomized design at 1-week intervals in the same dog. One group was not medicated. The dogs in the other groups received 2 mg/kg xylazine intramuscularly (IM) and a treatment of saline (control), 50, 100 or 300 micro g/kg of each atipamezole or yohimbine IM 0.5 hr later. Urine and blood samples were collected 11 times over the course of 24 hr. Urine volume, pH, specific gravity and creatinine values; osmolality, electrolyte and arginine vasopressin (AVP) values in both urine and plasma; and plasma atrial natriuretic peptide (ANP) concentration were measured. Both atipamezole and yohimbine antagonized xylazine-induced diuresis. The reversal effect of yohimbine was more potent, but not dose-dependent at the tested doses, in contrast with atipamezole. Both atipamezole and yohimbine exhibited similar potency in reversing the decreases in urine specific gravity, osmolality, creatinine, sodium and chloride concentrations and the increase in the plasma potassium concentration induced by xylazine. Both also inhibited xylazine-induced diuresis without significantly altering the hormonal profile in the dogs. A higher dose of atipamezole tended to increase the plasma ANP concentration. This may not be due only to actions mediated by alphasub(2)-adrenoceptors. Both drugs can be used as antagonistic agents against xylazine-induced diuresis in healthy dogs.