An increase in XXXX in brain may be a general mechanism for the effect of stress on sensitivity to @entity158 .

@entity836 @entity1522 @entity35 @entity535 @entity1337 @entity1510 @entity2340 @entity1286 @entity158 @entity4857 @entity669
The role of the stress-induced increase in the uptake of @entity2340 in brain in opioid-induced @entity1337 was investigated by modifying the uptake of @entity535 in brain with injections of competing @entity1522 . Blockade of @entity1337 by @entity4857 (200 mg/kg, i.p.) alone, and by @entity4857 and @entity669 (100 mg/kg, i.p.), but not by @entity4857 and @entity2340 (100 mg/kg, i.p.), was taken to indicate that an increase in the uptake of @entity2340 in brain was involved in opioid-induced @entity1337 . @entity1286 -induced @entity1337 exhibited by @entity35 that were habituated to the laboratory and not restrained did not involve an increase in the uptake of @entity2340 in brain. However, a mild form of restraint, or exposure to a novel environment interacted with @entity1286 to induce @entity1337 which involved an increase in the uptake of @entity2340 in brain. These stressors did not affect sensitivity to @entity158 in the absence of @entity1286 . @entity1337 induced by 3 hr of restraint, which was preventable by @entity836 (1 mg/kg, s.c.) but not reversible by @entity1510 (1 mg/kg, s.c.), also involved an increase in the uptake of @entity2340 in brain. It is concluded that the endogenous opioid-induced @entity1337 that is induced by stress alone and @entity1337 induced by stress interacting with @entity1286 , both depend on an increase in the uptake of @entity2340 into the brain.
