Decreased seizure threshold after intrahippocampal colchicine injection in rats.

Wet dog shaking elicited by perforant path stimulation is little affected by bilateral injection of colchicine into the dorsal hippocampal formation but virtually eliminated by bilateral injection into the ventral hippocampal formation. Injection of colchicine into either dorsal or ventral hippocampal formation lowers the threshold for eliciting forelimb clonus with rearing. This effect is more pronounced 8 weeks postinjection than 2 weeks postinjection when colchicine is injected in the ventral hippocampal formation. This suggests that inappropriate reactive synaptogenesis and/or neuronal degeneration continues for an extended period after intrahippocampal injection of colchicine, especially in the ventral hippocampal formation.