The induction of anesthesia was started with eptazocine 30 mg iv and thiopental 3-4 mg.kg-1 iv and the trachea was intubated smoothly following succinylcholine 40 mg iv. Then, they were given intravenous droperidol 0.15 mg.kg-1 with inhalation of 70% N2O and 30% O2. Good intraoperative muscle relaxation was obtained by dialferine or pancuronium.

Eptazocine caused a concentration-dependent inhibition against the [3H]-naloxone [( 3H]-NLX) specific binding to rat brain synaptic membrane in the absence of sodium cation and GTP (IC50; 7.83 +/- 1.57 microM). The ratios of IC50 values between the absence to the presence of sodium cation alone or sodium cation and GTP were 3.89 and 4.35, respectively. In addition, eptazocine (10 microM) also produced the significant decrease of [3H]-NLX specific binding in the mouse brain synaptic membrane