FACTORS THAT MODULATE INESCAPABLE SHOCK-INDUCED REDUCTIONS IN DAILY ACTIVITY IN THE RAT

Most behavioral and neurochemical changes produced by inescapable shoc k dissipate in 1-3 days. However, daily running activity is depressed for 14-42 days following one to three sessions of inescapable shock. I n the present experiments, we sought to determine whether factors know n to be important in the development of the short-term effects of expo sure to inescapable shock would also be important in the production of the long-term effect of inescapable shock on daily activity. Three fa ctors were examined: a) the escapability of the shock; short-term beha vioral changes generally do not occur if the shock is escapable; b) na ltrexone pretreatment; the opioid antagonist naltrexone typically prev ents many of the short-term behavioral sequelae of inescapable shock; c) treatment with the anxiogenic beta-carboline FG-7142; administratio n of this compound alone frequently mimics inescapable shock in its ab ility to transiently disrupt behavior. The inescapable shock-induced r eduction in daily activity did not depend upon escapability of the str essor. In addition, naltrexone did not prevent and FG-7142 did not ind uce the reduction in daily activity associated with stressor exposure.