Antibodies to GM1 ganglioside inhibit morphine analgesia.

It has been shown that the injection of antiganglioside serum into the periaqueductal gray matter of rats blocks morphine induced analgesia. This result is due to the action of antibodies to GM1 ganglioside since the specific removal of these antibodies from the antiserum with pure GM1 ganglioside eliminates the blocking activity. Specificity for GM1 ganglioside was further shown by the blocking activity of choleragenoid, which binds specifically to GM1 sites. Antibodies to other brain constituents, namely S-100 protein and myelin, did not block the morphine analgesia.