Stress-dependent enhancement and impairment of retention by naloxone: evidence for an endogenous opioid-based modulatory system protective of memory.
The opiate-receptor antagonist naloxone was administered to rats after passive-avoidance training either alone or in combination with forced-swim stress. A retention test revealed that while naloxone enhanced retention when administered alone, it impaired retention when administered in combination with forced-swim stress. The findings provide evidence for a "protective" endogenous opioid-based system that, when not blocked pharmacologically, limits enhancement or impairment of retention under conditions of mild and intense stress, respectively.
Schneider
Allen M
AM
Department of Psychology, Swarthmore College, Swarthmore, PA, United States. ASchnei1@Swarthmore.edu
Simson
Peter E
PE
Spiller
Krista
K
Adelstein
Jonathan
J
Vacharat
Amanda
A
Short
Kenneth R
KR
Kirby
Lynn G
LG
D000704:Analysis of Variance; D000818:Animals; D001362:Avoidance Learning; D004597:Electroshock; D008297:Male; D008568:Memory / Q000187:drug effects* / Q000502:physiology*; D008569:Memory Disorders / Q000139:chemically induced / Q000503:physiopathology; D009270:Naloxone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D009483:Neuropsychological Tests; D011897:Random Allocation; D051381:Rats; D020318:Rats, Long-Evans; D013315:Stress, Psychological / Q000503:physiopathology*; D013550:Swimming; D013997:Time Factors
D009292:Narcotic Antagonists; D009270:Naloxone