Repeated spatial acquisition: effects of NMDA antagonists and morphine.
Effects of morphine and 2 N-methyl-D-aspartate (NMDA) receptor antagonists, phencyclidine and LY235959, were studied using a within-subject, repeated-acquisition/performance procedure adapted to the Morris Swim Task. In the performance component, subjects swam to a hidden platform that was always in the same location in the pool. In the acquisition component, the platform was moved to a different place for each session. Baseline training produced rapid and direct swims to the platform in the performance component and steep within-session learning curves in the acquisition component. All 3 compounds increased swim distances, escape latencies, and slowed swim speed in a dose-dependent manner, but only morphine consistently produced selective impairments on acquisition. NMDA antagonists generally affected acquisition only at doses that also disrupted performance, although phencyclidine produced selective effects in some animals. These outcomes were different than those from studies of response chains in primates, suggesting that task and species variables may be important determinants of drug effects on acquisition.
Galizio
Mark
M
Department of Psychology, University of North Carolina at Wilmington, 28403-5612, USA. galizio@uncw.edu
Keith
Julian R
JR
Mansfield
Will J
WJ
Pitts
Raymond C
RC
D000701:Analgesics, Opioid / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D007546:Isoquinolines / Q000494:pharmacology; D008297:Male; D009020:Morphine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D016202:N-Methylaspartate / Q000037:antagonists & inhibitors*; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D010622:Phencyclidine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012691:Serial Learning / Q000187:drug effects*; D013028:Space Perception / Q000187:drug effects*
D000701:Analgesics, Opioid; D018691:Excitatory Amino Acid Antagonists; D007546:Isoquinolines; D009292:Narcotic Antagonists; D009270:Naloxone; D016202:N-Methylaspartate; D009020:Morphine; C088643:LY 235959; D010622:Phencyclidine