Proconvulsant effects of aminophylline during amygdala kindling in developing rats

Aminophylline (A) is a proconvulsant in adult rats. We studied the effect of A on amygdala kindling in 15-day-old rat pups. Production of generalized seizures was significantly promoted by A at doses ranging from 10 to 100 mg/kg. Terminal status epilepticus (TSE) was produced in 33% of pups receiving 25 mg/kg A, 75% of pups receiving 50 mg/kg A, and 100% of pups receiving 100 mg/kg A. The number of stimuli needed to produce a stage 4-5 generalized seizure was significantly smaller in animals receiving 10 mg/kg A (5.7 +/- 3.4), 25 mg/kg A (3.4 +/- 2.4), 50 mg/kg A (1.9 +/- 1.4), or 100 mg/kg A (1.9 +/- 1.6) than in saline-treated controls (12.3 +/- 3.7) (P less than 0.001). In addition, 16% of pups receiving 50 mg/kg and 33% of pups receiving 100 mg/kg A and never stimulated developed TSE. These seizure-promoting effects of A in rat pups undergoing amygdala kindling are far more dramatic and occur at far lower doses than those previously reported in adults.