Repeated electroconvulsive shock or chronic morphine treatment increases the number of 3H-D-Ala2,D-Leu5-enkephalin binding sites in rat brain membranes.
Experiments were performed in rats to evaluate the possible mechanisms responsible for the pharmacological cross-sensitization observed between repeated electroconvulsive shock (ECS) and chronic morphine administration. Repeated daily ECS for 9 days as well as chronic morphine pellet implantation resulted in a significant increase in the number of 3H-DADLE binding sites (Bmax values of 231 and 196 fmoles/mg protein, respectively). By contrast, single ECS, repeated sham ECS, and placebo pellet-treated rats all had significantly lower Bmax values (approx. 170 fmoles/mg protein). Affinities were not significantly altered by these treatments (Kd values between 3.1 and 4.0 nM). These data may link pharmacological cross-sensitization (repeated ECS and chronic morphine treatment) with a functional increase in the number of available opioid receptors.
D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000187:drug effects / Q000502:physiology; D004597:Electroshock; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives* / Q000378:metabolism; D016308:Enkephalin, Leucine-2-Alanine; D007700:Kinetics; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013574:Synaptosomes / Q000378:metabolism
D004743:Enkephalin, Leucine; D016308:Enkephalin, Leucine-2-Alanine; D009020:Morphine