Effects of Varied Culturing and Experimental Temperature on Electrical Membrane Properties in Paramecium

Abstract

Effects of temperature on the electrical properties of the Paramecium membrane were investigated under constant current and voltage-clamp stimulation. With cells cultured at 18 °C, the resting potential was largely stable with experimental temperatures varied over the range of 10–25 °C, whereas action potential amplitude and membrane input resistance were inversely related to temperature increases. During voltage clamp, the early calcium current was increased, the time-to-peak decreased, and the early conductance increased with temperature. Similar modifications of the culturing temperature did not affect the resting potential, input resistance and stimulus-response relationship of the action potential, but the early conductance was reduced with increase in temperature. Possible effects of long- and short-term temperature changes upon intraciliary calcium concentration are discussed.