[Mechanism of early receptor potential generation and an electrical model of retinal rods in rats].

A passive electric model of the retinal rod can reproduce the changes of the ELP-waveform at temperatures within the range 10 degrees--45 degrees C. R2-component of the ERP is generated by the process with the time constant ca. 500 microseconds (37 degrees C) and activation energy 31 kcal/mol characteristic of metarhodopsin I--metarhodopsin II transition. R1 originates not later than at prelumirhodopsin--lumirhodopsin conversion. Charge displacements are 0.006 (R1) and 0.04 (R2) electronic charges per rhodopsin bleached. The model is used for determining membrane capacitance and resistance of the rat retinal rod.