[Effect of short-term hypokinesia on the response of the opioid system in the rat].

The content of methionine-enkephalin, leucine-enkephalin and beta-endorphine was measured in various brain compartments (hypophysis, hypothalamus, midbrain, medulla oblongata, striatum), adrenals and plasma of the rats exposed to single and repeated immobilization. The reaction of the opiate systems to immobilization was very distinct in the emotiogenic brain structures (hypothalamus and midbrain) and hypophysis. The content of opiate-like peptides varied as a function of the immobilization time, with the most distinct changes occurring at the 150th minute. After daily immobilization repeated 40 times adaptation to the chronic stress-effect developed.