Susceptibility to pilocarpine-induced seizures in rats increases with age.

Systemic administration of high doses of the cholinergic agonist pilocarpine induces motor limbic seizures in rats. Susceptibility to the convulsant effects of pilocarpine increases during adult life: the threshold dose for generalized seizures is essentially constant from age 30 to 70 days, but decreases thereafter, particularly beyond age 100 days. The increase in seizure susceptibility continues up to at least age 200 days, (the oldest age studied).