Albino mice from a stock produced by nine generations of selection for high incidence of clonic-tonic seizures but low incidence of deaths in seizures were tested for susceptibility when started at 20, 25, 30, or 35 instead of the usual 15 days of age. There was a sharp decrease in susceptibility to clonic-tonic seizures and an increase in variability of response when the mice started at 25 days of age or later. When mice of the same stock which had had seizures regularly before 50 days of age were tested after 50 days of age they continued susceptible until death or near death, even when the life-span was relatively long. Offspring of crosses between mice of this stock and those of a stock selected for low seizure incidence had an average seizure incidence intermediate between those of the parent stocks, but no simple genetic explanation could be postulated. Mice of the high incidence stock which were mated without being tested for two generations produced offspring with decreased susceptibility, but still with a high proportion of individuals highly susceptible. These results show the necessity for standardization of stocks of mice and testing procedures in studies on audiogenic seizures. They support the view that inheritance of seizure susceptibility is multigenic and quantitative.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.