Differences in the methylation of brain histamine between audiogenic seizure-sensitive and -resistant deermice

Abstract

We have investigated the catabolism of [3H] histamine (HA), after intraventricular (i.vt.) administration, in brains of the audiogenic seizure susceptible (SS) and resistant (SR) deermouse . Brains of SS mice had lower endogenous HA levels and contained less [3H]-HA 20, 60 and 300 sec after i.vt. [3H]-HA than did brains of SR deermice. Twenty sec after [3H]-HA, brain [3H] methylhistamine (MeHA) levels and the resulting MeHA conversion index were found to be increased in the SS animals while later, at 60 and 300 sec, these parameters were found to be decreased. There were no SS-SR differences in the levels of brain [3H] methylimidazoleacetic acid. The data indicate that SS deermice catabolize exogenous HA, at least initially, more rapidly than their SR counterparts, confirming a like result noted immediately prior to seizure activity elicited by the administration of L-methionine-dl-sulfoximine in .