Electrical properties of smooth muscle cell membrane of opossum esophagus.

摘要: The electrical properties of the circular smooth muscle layer from North American opossum esophagus (body) were studied in vitro by microelectrode recording techniques, both at rest and during stimulation intramural inhibitory nerves. All observations made 37 degrees C an Abe-Tomita partitioned bath on strips dissected 2 cm orad lower esophageal sphincter. At rest, potential cell membrane was -49 +/- 4 mV (mean SE); length constant time 2.0 0.6 mm 120 16 ms, respectively. junction (IJP) elicited nerves followed a "rebound" or "off" response, characterized depolarization which spikes superimposed concomitant mechanical activity preparation that usually caused dislocation microelectrode. maximal IJP amplitude 35 mV, response reversed polarization to -90 suggesting due increase permeability toward potassium ions. invariability latency different distances stimulating electrodes (1.25-4 mm) suggests is largely diffusion transmitter nerve varicosities postsynaptic receptor sites. Depending rate, prolonged fusion continuous hyperpolarization membrane. faded with time, but off responses only observed after terminating stimulation. passive are comparable those other gastrointestinal muscles.(ABSTRACT TRUNCATED AT 250 WORDS)