THE IMPACT OF CHOLINERGIC DRUGS ON MILD SHOCK-INDUCED ANALGESIA PARALLELS THEIR IMPACT ON MEMORY. J.W. Grau and M.W. Meagher. Dept. of Psychology, Texas A&M University, College Station, TX 77843.

We have previously shown that mild shock (3, 0.75 sec, 1.0 mA) elicits a strong analgesia in rats on the tail-flick test. We have suggested that the memory of the aversive event mediates the activation of the analgesic sstems in this situation. If this is true, then cholinergic drugs which influence memory should have a parallel impact on the analgesia observed after mild shock. To test this, we first assessed the impact of the cholinergic antagonist scopolamine (0, 0.1, 1.0, 10 mg/kg), a drug which others have shown can disrupt memory. We found that scopolamine also disrupts mild shock-induced analgesia. We then tested the impact of the anticholinesterase, physostigmine. Others have reported that low doses of this drug enhance memory, while high doses disrupt memory. We found that this drug has a similar impact on mild shock-induced analgesia: low doses of physostigmine (0.1 mg/kg) potentiated, and a high dose (0.5 mg/kg) attenuated, the analgesia. Others have suggested that these analgesic efects can only be observed if subects receive baseline testing prior to the administration of shock (Gower, A.J. & Tricklebank, M.D., Neuropharm., 25, 1161, 1986). We tested this hypothesis and found that mild shock induced a strong analgesia, and a low dose of physostigmine (0.1 mg/kg) potentiated this analgesia, irrespective of whether or not the subjects received baseline testing.

Published in Society for Neuroscience Abstracts, 14, 1988.

Return to reprint request page.