Although there is an abundance of evidence which indicates that ATP is released as well as taken up by cells, the concept that ATP cannot cross the cell membrane has tended to prevail. This article reviews the evidence for the release as well as uptake of ATP by cells. The evidence presented by various investigators clearly indicates that ATP can cross the cell membrane and suggests that the re...

To achieve these goals, we need to determine the environmental factors and underlying physiological mechanisms that regulate the uptake and effects of toxic metals (Cu, Cd, and Zn) and interactive nutrient metals (Mn, Zn and Fe) in representative phytoplankton species. We will then combine this information with data on environmental variations in controlling factors (e.g. free ion concentration...

Previously, we have shown that renal proximal tubular cells (RPTCs) recover physiological functions after injury induced by the oxidant tert-butylhydroperoxide (TBHP), but not by the nephrotoxic cysteine conjugate dichlorovinyl-l-cysteine (DCVC). This study examined the role of protein kinase C (PKC) in the repair of RPTC functions after sublethal injury produced by these toxicants. Total PKC a...

Researchers have, for decades, contributed to an increased collective understanding of the physiological demands in cross-country skiing; however, almost all of these studies have used either non-elite subjects and/or performances that emulate cross-country skiing. To establish the physiological demands of cross-country skiing, it is important to relate the investigated physiological variables ...

On the basis of these facts about freshwater fish and invertebrates: (i) the Na+ turnover is a physiological process associated with the gill membranes; (ii) the key mechanism of acute silver toxicity consists of reduction in Na+ uptake by blockade of gill Na+,K+-ATPase; (iii) the mass-specific surface area of the gills depends on animal body mass; and (iv) the gill surface is also the major si...