Circadian rhythm of electrical activity and motility of the stomach in cats and their relation to sleep-wakefulness stages.

Abstract

Med., 1983, 141 (3), [275][276][277][278][279][280][281][282][283][284][285][286] Polysomnographic recordings were done over continuous 3 days together with those of electrical and mechanical activities of the stomach using chronically implanted electrodes and forcetransducer in unanesthetized and unrestrained state of 4 adult cats. Circadian rhythm of the basic electric rhythm (BER) and mechanical activity in the stomach accustomed to feeding schedule of once a day was divided into the two; the fed state from the end of feeding to 8 to 11 hr later and the succeeding fasting state. However, differentiation of the fasting state into the contractile and uncontractile periods, which is known in dogs, was not evident in cats. The mean BER interval was longer and the standard deviation was smaller in the fed state than in the fasting state. Among stages of wakefulness (W), drowsiness (D), light slow wave sleep (LS), deep slow wave sleep (DS) and REM sleep, the mean BER intervals in every total time during the fed state were compared with one another. A definite unidirectional finding obtained in all 4 cats was only that the mean BER intervals in the stage D were longer significantly than those in the stage W. ---gastric activity; circadian rhythm; sleep; REM So far, diurnal changes in motor and/or electrical activities of the stomach have been studied, using open tipped catheter in humans (Bloom et al. 1970), extraluminal force-transducer in dogs (Itoh et al. 1977;Kamihogi 1977) and in turkeys (Duke and Evanson 1976) and extraluminal electrodes in dogs (Kamihogi 1977). In cats, however, electrical activities of the stomach were recorded only in anesthetized state (Bozler 1945) and together with mechanical activities also only in isolated preparations (Bortoff and Weg 1965). Since, in this way, little has been known on gastric activities in unanesthetized and unrestrained cats, the first objective of the present study was to provide baseline data of diurnal gastric activities in cats.Cats have been, on the other hand, subjected to the study of sleep-wakefulness cycle in animals for the most part. However, we have no similar information in cats as in dogs (Kamihogi 1977) on how rhythms of sleep and waking influence upon gastric activities. Thus, the second objective of this research was to clarify their influence mainly on the electrical activities of the stomach in cats.