Development of physical dependence on morphine not accompanied with tolerance formation.
The development of tolerance induced by daily repeated administration of 10 mg/kg of s.c. morphine was suppressed by combined injection of adrenergic blockers, 10 mg/kg i.p. phentolamine or propranolol, in mice. However, this treatment could not prevent the development of physical dependence as evidenced by the naloxone precipitated abstinence signs. Thus, we provide a new evidence that morphine analgesia, tolerance and physical dependence is dissociable from each other.
Ohta
A
A
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Nagasaki University, Japan.
Kaneto
H
H
D000698:Analgesia; D000818:Animals; D004347:Drug Interactions; D004361:Drug Tolerance; D007274:Injections, Intraperitoneal; D007279:Injections, Subcutaneous; D008297:Male; D051379:Mice; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D009021:Morphine Dependence; D009270:Naloxone / Q000008:administration & dosage / Q000494:pharmacology; D010646:Phentolamine / Q000008:administration & dosage / Q000494:pharmacology*; D011433:Propranolol / Q000008:administration & dosage / Q000494:pharmacology*
D009270:Naloxone; D009020:Morphine; D011433:Propranolol; D010646:Phentolamine