Nigral muscimol infusions facilitate the development of seizures in immature rats.

Since recent data utilizing GABAergic stimulation of the substantia nigra (SN) suggest that the SN is a crucial site in a circuitry involved in the modification of seizures in adult rats, the role of the SN was investigated in seizures of rat pups. Bilateral nigral infusions of the GABA agonist muscimol partially protected adult rats against flurothyl-induced seizures, while similar infusions actually facilitated the development of flurothyl seizures in 15-day-old rat pups. These results suggest that age-related differences in the nigral GABA sensitive system may account for the increased susceptibility to generalized seizures of the developing brain.