Effects of passive immunization with rabbit anti-phenobarbital IgG on cyclobarbital-induced sleeping time and hepatic enzyme activities of C3H mice.

Effects of normal rabbit IgG (N-IgG) and phenobarbital specific IgG (Ab-IgG) on cyclobarbital-induced sleeping time were studied. Ab-IgG was specifically purified by Immunoadsorbent from rabbit antisera obtained by immunization with p-azophenobarbital bovine gamma globulin. N-IgG was purified from normal rabbit sera by DEAE-cellulose chromatography. The aggregate-free IgG were passively immunized to C3H mice 1 hr before intraperitoneal injection of cyclobarbital which has a high binding affinity to the antibodies. The pretreatment with N-IgG prolonged significantly cyclobarbital-induced sleeping time as compared with that of saline treated group, however, in the Ab-IgG treated group the duration of the sleeping was much the same as that seen in the saline group. To determine whether Ab-IgG has any influence on barbiturate tolerance, effects of N-IgG and Ab-IgG on the activities of hepatic enzymes in 9,000 X g supernatant (alkaline RNase and aminopyrine demethylase) of the mice were examined at 40 hours after cyclobarbital administration. The activities of both enzymes which could be induced by cyclobarbital were decreased significantly in Ab-IgG treated group as compared with those on N-IgG group. These results are discussed with relation to barbiturate tolerance.