INDUCED BEHAVIOR DURING PRECIPITATED ABSTINENCE IN RATS

Active avoidance, hypothalamic self-stimulation and deprivation-induced water-drinking were examined in rats during the lengthy somnolent phase of precipitated morphine abstinence. Avoidance behavior occurred at the control level but only if amphetamine was administered to counteract the somnolence. It was necessary to increase the current progressively during abstinence to keep the rate of self-stimulation at the control level. Deprivation-induced drinking was absent during the 1st h of abstinence precipitated during the day and much reduced in a night-time test. Both groups eventually made up their deficits as accurately as control rats do, the only difference being that a longer tie was required. The neural subsystems serving memory and the exceution of learned behaviors apparently still function normally during abstinence. The functional impairment seen in this state appears only to involve the brain areas controlling awareness of the environment, both external and internal. Possible involvement of the ascending dopaminergic system is discussed.