Epileptogenic effects of skin extracts from the Australian frog Pseudophryne coriacea after intracerebral microinfusion in rats.

The behavioural and electrocortical (ECoG) effects induced by a methanol extract of the skin of the Australian frog Pseudophryne coriacea, directly microinjected into several areas of the brain, were studied in freely moving rats. Administration of the P. coriacea extract (5, 10, 15 and 20 micrograms) into the dorsal hippocampus produced a dose-dependent and reversible behavioural stimulation and ECoG spikes lasting 20-140 min. Similar but less intense effects were elicited in rats receiving injections into the III cerebral ventricle, amygdala and caudate nucleus. In conclusion, the present experiments show that the skin extract of P. coriacea produces behavioural stimulation and ECoG spikes when injected into the rat brain, the most sensitive area being the hippocampus.