EFFECT OF GABA RECEPTOR AGONISTS OR ANTAGONISTS ON MORPHINE-INDUCED STRAUB TAIL IN MICE

Abstract

The effects of GABA receptor agents on Straub tail induced by morphine were investigated in mice. Subcutaneous injection of different doses of morphine (10–60 mg/kg) induced a dose-dependent Straub tail in mice. Maximum response was obtained with 40 mg/kg of the drug, 30 min after the drug administration. The morphine response was decreased by subcutaneous injection of naloxone (0.5–2 mg/kg). Intraperitoneal administration of different doses of baclofen (2–8 mg/kg) reduced Straub tail induced by morphine (40 mg/kg). The response of baclofen was decreased by Intraperitoneal injection of CGP35348 (150 mg/kg). CGP35348 by itself did not elicit any response. Different Intraperitoneally doses of muscimol (1–4 mg/kg) bicuculline (1–3 mg/kg), or picrotoxin (1–3 mg/kg) also reduced morphine effect. The effect of muscimol was not altered by bicuculline pretreatment. It is concluded that both GABAA and GABAB receptor activation reduced Straub tail induced by morphine.