Changes in mu opiate receptors following inescapable shock.
Rats exposed to inescapable shock exhibit profound hypoalgesia. Pharmacological evidence has suggested that changes in endogenous opiate activity may be responsible for the hypoalgesic response. We measured the binding of [3H]DAGO, a selective mu-opiate receptor agonist, in brains of rats exposed to no shock, inescapable shock, or escapable shock. Binding of [3H]DAGO in the midbrains of rats in the inescapable shock group was decreased relative to the other two groups. The decrease in binding appeared to result from a decrease in number of mu-receptors and not a change in affinity. These results support the hypothesis that inescapable shock produces long-term changes in endogenous opiate systems.
Stuckey
J
J
Laboratory of Clinical Science, NIMH, Poolesville, MD 20837.
Marra
S
S
Minor
T
T
Insel
T R
TR
D000818:Animals; D004597:Electroshock; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004745:Enkephalins / Q000378:metabolism; D008297:Male; D008636:Mesencephalon / Q000378:metabolism* / Q000503:physiopathology; D051381:Rats; D011957:Receptors, Opioid / Q000378:metabolism*; D017450:Receptors, Opioid, mu; D013312:Stress, Physiological / Q000378:metabolism*
D004745:Enkephalins; D011957:Receptors, Opioid; D017450:Receptors, Opioid, mu; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-