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 general survey of experimental evidence showing the wide variety of membrane- linked mechanisms that are perturbed by changes in hydrostatic pressure, it will focus on the pressure-sensitivity of the processes involved in ionic and osmotic regulation in crabs and fish, including membrane-localized ATPases and oxidative metabolism. The results of long-term exposure (30 days) of freshwater eels Anguilla anguilla at 101 ATA of hydrostatic pressure clearly indicate Na+ balance impairment at the tissue level (muscle and gill). That impairment occurs at the same time as a new state of energetic metabolism which results from adjustments of intertissue coupling of anaerobic and aerobic metabolisms. Considering its life cycle, however, Anguilla can reasonably be considered as ‘preadapted’ to pressure. Experiments conducted on the crab Eriocheir sinensis, which normally never encounters high levels of pressure, show that physiological processes involved in hydromineral balance control are outstandingly resistant to pressure. Disturbances in hydromineral balance and energetic metabolism are rapidly corrected and adjusted to a new state of activity.