Cell Transport and Regulation of Ca2+, Mg2+,
H+, amino acids, Cell Volume Regulation
The goal of our laboratory is to determine how skeletal muscle cells regulate their intracellular environment in response to changes in their needs and function as well as in response to alterations in their extracellular environment. Three main lines of research are pursued: i) Study of the molecular mechanisms of ionic translocation mediated by the sarcolemmal Na+/Ca2+ exchanger and the Ca2+ pump; ii) Characterization of the mechanisms of transport of Mg2+ across the sarcolemma; and iii) Study of the mechanisms by which cells sense and maintain their volume under resting conditions and in response to contraction and changes in the extracellular environment.
Two experimental models are used. The first consists of internally perfused, voltage-clamped, barnacle skeletal muscle cells. This preparation is used to study membrane transport of solutes under conditions in which all the relevant physiological parameters are measured and controlled (i.e., membrane potential , composition of the intra and extracellular environment, membrane tension, and intracellular pressure). The second preparation consists of intact barnacle muscle cells whose basal end is mounted in a glass cannula (to measure intracellular pressure) and the tendon end is mounted in a force transducer. This preparation is used to measure the effect of electrical stimulation on cell volume, isometric force, and intracellular pressure.