Central versus peripheral actions of Leu-enkephalin on acquisition of a one-way active avoidance response in rats.
A comparison was carried out of the effectiveness of intracerebroventricular or intraperitoneal administration of Leu-enkephalin to affect acquisition of a one-way active avoidance response, locomotor activity or shock sensitivity. Leu-enkephalin impaired acquisition of the avoidance response only when administered peripherally. In contrast, either central or peripheral administration of Leu-enkephalin increased locomotor activity in the open field, and Leu-enkephalin also produced analgesia when administered directly into the brain. The pattern of results suggests that Leu-enkephalin acts at a peripheral site to influence avoidance conditioning.
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D004597:Electroshock; D004743:Enkephalin, Leucine / Q000008:administration & dosage* / Q000494:pharmacology; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D010525:Peripheral Nerves / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains
D004743:Enkephalin, Leucine