[The influence of bemegride on frog spinal cord root potentials]

The effect of the convulsant bemegride (beta-ethyl-beta-methyl-glutharimide) on the electronic potentials in the frog spinal roots was investigated in situ. Intravenous injection of the bemegride subconvulsant doses (6.8 +/- 2.7 mg/kg) depressed rapidly the electrotonic dorsal root potentials (DRP) evoked by a stimulation of the adjacent dorsal root (DR) or the ventral root (VR). They were reduced by 55--67% 3-6 min after the bemegride injection. The effect of bemegride was reversible and the DRP amplitude restored its initial value within an hour. Ventral root potentials after bemegride injection revealed only greater amplitude fluctuations. A conclusion is made that bemegride is a selective and potent depressor of the primary afferent depolarization in the frog spinal cord.