Sensitivity to continuous administration of pentobarbital in different strains of mice.

The comparisons of responses to pentobarbital by pellet implantation method with respect to cumulative mortality, narcosis and tolerance development on five strains (ICR, ddY, ddN, C57BL, and C3H) of mice were studied. C3H mice showed most susceptible and sensitive to pentobarbital among the five strains of mice tested. ICR mice were most resistant to the treatment. It appears that the effects of genetic variation could be of importance for future studies in gaining insight of the mechanism of barbiturate tolerance.