[Left and right brain hemispheres in the regulation of pain sensitivity biorhythms in mice during stress]

The foot-shock effects on ultradian and circadian rhythms of pain sensitivity in the SHR mice were studied after unilateral brain cortex hemisphere inactivation by means of the Leao spreading depression. Under acute painful stress, the left hemisphere partially loses its synchronizing effect on circadian rhythm and supports the 12-hour and particularly 6-hour periodicities. The left hemisphere effect dominates in intact animals under stress. The right hemisphere under the same conditions mainly loses its activating effect on circadian rhythm and supports the 8- and 16-hour periodicities. The right hemisphere effect dominates in animals under stress operated 2-3 days prior to the experiment.