Relations between nicotine-induced convulsive behavior and blood and brain levels of nicotine as a function of sex and age in two inbred strains of mice

Nicotine levels in blood and whole brain were measured as a function of sex and age in C57BL/6J and DBA/2J mice and compared to the behavioral responses following an intraperitoneal injection of nicotine. The results indicate that blood levels of nicotine alone do not accurately predict either brain levels of nicotine or the behavioral responses to a single injection of nicotine. It general, brain levels of nicotine proved to be a fairly accurate predictor of the behavioral responses to nicotine. The data indicate that the sexes differ in their sensitivity to nicotine. Forty-two-day-old male mice of both strains given comparable doses of nicotine were found to concentrate the drug in the brain more than females. However, there was no corresponding increase in sensitivity to this increased brain concentration as measured by LD50, ED50, latency to tremor or latency to death.