Effects of [D-Ala2] Met-enkephalinamide, a Met-enkephalin analog, on delayed response by squirrel monkeys.
Squirrel monkeys were tested on an indirect spatial delayed response task after subcutaneous injections of either physiological saline, 100, or 500 microgram/kg [D-Ala2] methionine enkephalinamide (DAME). During Experiment 1 monkeys completed two-choice delayed response problems with 0-, 6-, 12- and 18- sec delays; DAME significantly enhanced performance at 18-sec delays but not for the shorter delay. During Experiment 2, monkeys performed a nine-choice spatial delayed response task with 0-, 4- and 8-sec delays. In Experiment 2, low but not high doses of DAME impaired performance. Memory functions represented by a bias-free performance measure paralleled percentage correct in both experiments. Therefore, DAME effect, in enhancing and in impairing performance, were not attributable to changes in the relative number of systematic spatial errors (positional win-shift; lose-stay, position perseveration, and position preference).
Scott
A G
AG
University of Arizona, Tucson 85721.
King
J E
JE
Michels
R R
RR
Fobes
J L
JL
D000818:Animals; D001143:Arousal / Q000187:drug effects*; D001288:Attention / Q000187:drug effects*; D001921:Brain / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D008297:Male; D008568:Memory / Q000187:drug effects*; D011939:Mental Recall / Q000187:drug effects*; D011340:Problem Solving / Q000187:drug effects; D011597:Psychomotor Performance / Q000187:drug effects*; D011930:Reaction Time / Q000187:drug effects; D011957:Receptors, Opioid / Q000187:drug effects; D012453:Saimiri
D011957:Receptors, Opioid; D004744:Enkephalin, Methionine; C022118:enkephalinamide-Met, Ala(2)-