Different epileptogenic activities of murine and ovine corticotropin-releasing factor.

The behavioral and EEG effects of rat and ovine corticotropin releasing factor (r- and o-CRF) were compared. Both peptides were injected intracerebroventricularly into rats through chronically implanted cannulae. At the doses of 0.1 and 1 microgram both peptides activated the EEG and stimulated motor activity. At the dose of 10 micrograms they produced spiking activity. However, while o-CRF-induced spiking activity was present both in the hippocampus and in the cortical leads and was associated with generalized myoclonic movements, that induced by r-CRF was confined in the hippocampus and was not accompanied by myoclonic movements. Spiking activity induced by r-CRF was suppressed by verapamil, but was not influenced by naloxone.