“In task 1, saline control animals showed good retention in a test session carried out 24 hr later; beta-endorphin, ACTH and epinephrine caused amnesia; beta-endorphin potentiated the amnesic effect of ACTH and epinephrine; and naloxone caused memory facilitation and reversed the amnesic effect of ACTH and epinephrine.”
“In task 2, control animals showed poor retention; beta-endorphin caused amnesia at the dose of ….1 but not 1.0 microgram/kg; the other three drugs caused memory facilitation; naloxone potentiated the facilitatory … of ACTH and epinephrine ; and beta-endorphin reversed it and … it into a deep amnesia.”