PRESSURE EFFECTS ON MEMBRANE-BASED FUNCTIONS AND ENERGY-METABOLISM - A REVIEW

This review will consider the effects of hydrostatic pressure on some cellular functions related to membrane-localized processes. After a ge neral survey of experimental evidence showing the wide variety of memb rane-linked mechanisms that are perturbed by changes in hydrostatic pr essure, it will focus on the pressure-sensitivity of the processes inv olved in ionic and osmotic regulation in crabs and fish, including mem brane-localized ATPases and oxidative metabolism. The results of long- term exposure (30 days) of freshwater eels Anguilla anguilla at 101 AT A of hydrostatic pressure clearly indicate Na+ balance impairment at t he tissue level (muscle and gill). That impairment occurs at the same time as a new state of energetic metabolism which results from adjustm ents of intertissue coupling of anaerobic and aerobic metabolisms. Con sidering its life cycle, however, Anguilla can reasonably be considere d as 'preadapted' to pressure. Experiments conducted on the crab Erioc heir sinensis, which normally never encounters high levels of pressure , show that physiological processes involved in hydromineral balance c ontrol are outstandingly resistant to pressure. Disturbances in hydrom ineral balance and energetic metabolism are rapidly corrected and adju sted to a new state of activity.