[Experimental hepatic encephalopathy. Study of the organization of a diurnal sleep pattern in rats with portocaval anastomosis].

The organization of the diurnal sleep pattern was studied in control rats and in rats with end-to-side portocaval shunt before operation and during five weeks after operation. In control rats, no modification of the states of sleep was observed during the experimentation. In shunted rats, the total duration of waking increased, the total duration of slow wave sleep and paradoxical sleep decreased. The number of phases of waking and slow wave sleep increased and the number of phases of paradoxical sleep decreased. The mean duration of the phases of slow wave sleep decreased. These results show that the electrophysiological expression of experimental hepatic encephalopathy is similar to the electroclinical expression of hepatic encephalopathy in man and the polygraphic study of sleep disturbances permits the description of the encephalopathies.