The effects of apamin in rats with pretrigeminal or high spinal transsection of the central nervous system.

Rats were injected in one lateral cerebral ventricle (i.c.v.) with apamin (100 ng per animal). The resulting desynchronisation pattern in the electrocorticogram (ECoG) and the symptoms of poisoning were monitored before and after transsection at different levels, and following morphine. Apamin acts primarily on the brain stem and spinal cord, i.e. structures possessing a sensory input, and then indirectly on the higher integrating systems. There is no general parallelism between receptor density and locus of action.