Electrophysiological Analysis of Calcium Channels in Human Lower Esophageal Sphincter Smooth Muscle Cells

Background To investigate the characteristics and regulatory mechanisms of calcium channels in the human lower esophageal sphincter (LES) using the patch clamp technique, focusing on the differences between sling and clasp fibers. Methods Smooth muscle cells from the LES were isolated from 22 patients undergoing esophagectomy for middle thoracic esophageal carcinoma. Sling and clasp fibers were dissected, and single cells were prepared using collagenase and papain. Calcium currents were recorded using the whole-cell patch clamp technique with holding potentials of −60 mV and − 90 mV. The effects of nifedipine on calcium currents were also examined. Results Conclusion The LES smooth muscle cells primarily utilize L-type calcium channels for calcium influx, which are highly sensitive to nifedipine. No significant differences were observed between sling and clasp fibers in terms of calcium channel characteristics. These findings provide insights into the mechanisms underlying LES function and potential therapeutic targets for esophageal motility disorders.