[Analysis of the electrophysiologic characteristics of the trabecular membrane in the atria of frogs by recording ionic currents during potential fixation. II. Accomodation. Repeated responses. Anode-breaking excitation].

Measurements were carried out by the method of double succrose gap. Accommodation was practically absent in all the preparations studied: the minimal gradient was not observed, the mean value of accommodation was 0.02 rheobasa/s, saturation current/H practically coincided with the current of rheobase IO(IH/IO = 1.0 +/- 0.1). Repeated responses were initiated in 1/3 of samples. The current of initiating the repeated responses IRR was insignificantly higher than the rheobase one (IRR/IO = 1.2 +/- 0.1). In the samples where the replated responses were absent the effect of uneven depolarization was observed. At depolarization current which was insignificantly higher than the threshold one (IO), the potential did not return to the resting potential and was settled at the level of -20 mV. Anode disconnecting excitation was absent in all the samples. The hyperpolarization level varied from -90 to -160 mV. The data obtained well agree with the results of the analysis of the mathematical model of frog auricle trabecula membrane constructed on the basis of the data on the potential fixation.