Opioid μ-deficient CXBK mouse and the role of μ1-receptors in electrically induced convulsions

Studies were made on the role of μ1-receptors on electrically induced convulsions in mice. A relatively selective μ1-agonist, DAGO ([ d -Ala 2 -N- methyl-Phe 4 - Gly-ol]-enkephalin ) decreased the durations of tonic and clonic convulsions in C57BL/6 mice, but not in opioid μ-deficient CXBK mice, indicating that the activation of μ1-rreceptors had an anticonvulsive effect on these convulsions in mice. The selective μ1-antagonists naloxonazine and naltrexonazine promoted the clonic phase of electrically induced convulsion in C57BL/6 mice. Moreover, the duration of the clonic phase was longer in μ-deficient CXBK mice than in C57BL/6 mice. These data for CXBK mice confirmed, at least some proconvulsant effects of μ1-antagonists in C57BL/6 mice. Thus, blockade of μ1-receptors has a proconvulsant effect, and μ1-receptors have at least some protective role against electrically induced convulsions.