Blockade of morphine analgesia by intracerebroventricular or subarachnoid injections of cholecystokinin in rats
Abstract
The analgesic effect of morphine 5 mg/kg sc in rats was dose-dependently attenuated by intracerebroventricular(icv) or intrathecal(ith) injections of octapeptidecholecystokinin(CCK-8) 1-4 ng,while unsulfated cholecystokinin(CCK-us) was ineffective. CCK-8 4 ng icv or ith had no significant effect on the pain threshold as measured by tail flick latency.
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