Propranolol Blocks the Stimulatory Effects of Naloxone on Ventilation and Oxygen Consumption in Hamsters

• Published in: Comparative biochemistry and physiology. A, Comparative physiology Comparative physiology, 1997-06, Vol.117 (2), p.177-182
• Main Authors: Schlenker, Evelyn H, Eikanger, Jeff
• Format: Article
• Language: English
• Subjects: Adrenergic beta-Antagonists - administration & dosage; Adrenergic beta-Antagonists - pharmacology; Animals; body temperature; Body Temperature - drug effects; catecholamines; Cricetinae; Dose-Response Relationship, Drug; Hamster; Male; Mesocricetus; naloxone; Naloxone - antagonists & inhibitors; Naloxone - pharmacology; oxygen consumption; Oxygen Consumption - drug effects; propranolol; Propranolol - administration & dosage; Propranolol - pharmacology; Pulmonary Ventilation - drug effects; Respiration - drug effects; Tidal Volume - drug effects; ventilation
• ISSN: 0300-9629; 1096-4940
• DOI: 10.1016/S0300-9629(96)00263-0

The purposes of these studies were: 1) to determine the effects of various doses of propranolol, a nonspecific β-adrenergic antagonist, on ventilation, oxygen consumption, and body temperature in hamsters, and 2) to test the hypothesis that in hamsters the stimulatory effects of naloxone, an opioid receptor antagonist, on ventilation and oxygen consumption occur, at least in part, through the release of catecholamines that act via β-adrenergic receptors. Propranolol, a non-specific β adrenergic receptor antagonist, at a 20 mg/kg depressed body temperature, oxygen consumption, tidal volume, and ventilation relative to saline. The lower dose of 10 mg/kg had only transitory effects on tidal volume at 60 min and ventilation at 30 min post-injection. Naloxone (1 mg/kg) relative to saline stimulated ventilation and oxygen consumption. These effects were blocked by propranolol pretreatment. The results of these experiments demonstrate that in the hamster, 1) body temperature, oxygen consumption, and ventilation appear to be modulated by β-adrenergic receptors, and 2) the stimulatory effects of naloxone on oxygen consumption and ventilation may occur through the interaction of endogenous opioids and β-adrenergic receptor systems.