Quantification of the analgesic activity of narcotic antagonists by a modified hot-plate procedure.

摘要: The analgesic activity of morphine and the narcotic antagonists, pentazocine, cyclazocine, levallorphan nalorphine, was assessed in rat using two hot plates: one maintained at 49.5 degrees C other "standard" 54.5 C. effects plate were a significantly greater magnitude than its for both nontolerant morphine-tolerant subjects. Dose-related observed with all antagonists tested plate; only highest dose pentazocine exhibited plate. Naloxone (3.0 mg/kg) antagonized but without itself when doses as high 30 mg/kg. Aspirin also inactive plate, whereas physostigmine increased latencies that produced severe motor deficit. A low temperature is recommended evaluating rat. This simple procedure provides results which are dose-related, quantifiable, reproducible, large specific.