Effects of analgesics and CNS-acting drugs on struggling following repetitive stimulation of the tail, and flexor reflex to a single stimulation of the sciatic nerve in rats.
Utilizing struggling to a repetitive stimulation of the tail, as a pain response, flexor reflex to a single stimulation of the sciatic nerve, as a spinal reflex activity, the analgesic activity and the muscle relaxant activity of certain analgesics were assessed alternately. Stable and reproducible response to a repetitive stimulation of the tail or a single stimulation of the sciatic nerve was obtained over a period of 5 hr, and quantitative measurement of struggling could be made. The 50% inhibitory doses of various drugs to struggling and flexor reflex were as follows (mg/kg, i.p.): morphine, 3.30 & 6.60, respectively; codeine, 12.80 & 24.00; pentazocine, 7.80 & 12.20; indomethacin, 4.60 & no effect; aspirin, 94.00 & no effect; baclofen, 1.04 & 2.20; chlorpromazine, 2.45 & 0.75; diazepam, 0.45 & 0.86; mephenesin, 36.00 & 32.00. Based on these results, it is suggested that the method is useful for quantitative measurement of analgesia and muscle relaxation.
D000700:Analgesics / Q000494:pharmacology*; D000758:Anesthesia; D000818:Animals; D004558:Electric Stimulation; D008297:Male; D009125:Muscle Relaxants, Central / Q000494:pharmacology*; D010146:Pain / Q000503:physiopathology*; D051381:Rats; D012018:Reflex / Q000187:drug effects*; D012584:Sciatic Nerve / Q000502:physiology; D013623:Tail
D000700:Analgesics; D009125:Muscle Relaxants, Central