The influence of nociceptive stimuli on the convulsant action of camphor

Abstract

The effect of nociceptive (pain) stimulation on the convulsant effect of camphor was studied on white mice and guinea pigs. Camphor was injected subcutaneously in a dose of 1 mg/g to mice and intraperitoneally in a dose of 0.20–0.24 mg/g to guinea pigs. Convulsions in mice were recorded visually and evaluated according to the 5-point system (0-absence of convulsions, 5-death); in guinea pigs convulsions were registered actographically and recorded on a kymograph. Camphor was injected 2 minutes following discontinuance of the stimulation, which lasted 3 minutes in mice and ten minutes in guinea pigs. Experiments proved that following nociceptive stimulation, the times of onset of convulsions, as compared with controls, are postponed, the convulsions occur in a smaller number of animals, while the intensity of the already developed convulsions becomes lower. The authors hold that these effects of nociceptive stimulations on the convulsant effect of camphor are evidently caused by the development of inhibition in the central nervous system, preventing the convulsive attack.