Elevation of aversive threshold in rats by intra-amygdaloid injection of morphine sulphate.
Bilateral micro-injection of morphine sulphate (10 microgram, 20 microgram) into the cortico-medial amygdala produced a dose-dependent increase in aversive threshold. Similar injections into the basolateral amygdala or caudate-putamen failed to have any consistent effect on aversive thresholds. Whilst overall activity levels remained unaffected by morphine injection into either amygdaloid site, caudate animals exhibited a significant decrement in total activity in response to both morphine and control injections. Results are discussed with reference to a possible role for limbic mechanisms in morphine analgesia.
D000679:Amygdala; D000818:Animals; D002421:Caudate Nucleus; D004924:Escape Reaction / Q000187:drug effects*; D007267:Injections; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects; D011699:Putamen; D051381:Rats; D011930:Reaction Time / Q000187:drug effects
D009020:Morphine