RAT STRAIN AND AGE-DIFFERENCES IN KAINIC ACID-INDUCED SEIZURES

This study reports comparative dose-response data for kainic acid (KA) induced seizures in juvenile (35-40 days old) and adult (70-90 days o ld) Wistar-Furth (WF), Fisher 344 (F344), Sprague-Dawley (SD) and Long -Evans Hooded (LEH) rats. Juvenile male WF (n = 51), F344 (n = 55), SD (n = 60), LEH (n = 50) and adult male WF (n = 48), F344 (n = 52), SD (n = 52), LEH (n = 53) rats were given KA 6, 8, 10, 12 or 14 mg/kg, sc . As previously demonstrated adult WF and F344 rats showed the greates t sensitivity and most reliable convulsant responses to kainic acid; S D and LEH rats were less sensitive and showed more variable convulsant responses. Regardless of strain, all juvenile rats exhibited greater sensitivity and less variable convulsant response to KA compared to ad ults. This was most evident in juvenile SD and LEH rats. Results sugge st that while seizure sensitivity to KA decreases with age, genetic fa ctors may regulate the expression of this resistance.