LONG-TERM VARIATIONS OF ARTERIAL BLOOD-PRESSURE DURING SLEEP IN FREELY MOVING CATS

Using a new telemetric system for arterial blood pressure recordings, we have investigated long-term postoperative changes in blood pressure during sleep in freely moving cats. Particular attention was paid to the transitional periods at the beginning and end of paradoxical sleep (PS), as well as to the relationships between the blood pressure and ponto-geniculo-occipital (PGO) waves. In the initial postoperative sta ge lasting 2 to 5 days, the blood pressure decreased during the transi tion from slow wave sleep (SWS) to PS and maintained its lower level u ntil the end of PS. In contrast, in the later chronic stage, the blood pressure increased tonically during the transition from SWS to PS and maintained its higher level throughout PS on which several phasic ris es in blood pressure were superimposed. A significant increase in arte rial pressure during the transitional period began shortly after the f irst appearance of PGO waves. On the other hand, significant phasic ri ses in arterial pressure during PS shortly preceded the onset of PGO w ave bursts.