Small intestines were removed after animals were euthanized following sedation with isoflurane and cervical dislocation. Tissues were placed in oxygenated cold (4°C) KRB for further preparation.
After fine dissection of the mucosa and submucosa small preparations (approximately 10 mm2) were pinned, with the luminal side of the circular muscle up, to Sylgard elastomer-coated bases of 35 mm polypropylene dishes (Corning Glass Works, Corning, NY, USA).
Cells were impaled with glass microelectrodes filled with 3 M KCl and having resistances between 80 and 120 MΩ. Transmembrane potentials were measured using a high input impedance amplifier (Axon Instruments/Molecular Devices Corp., Sunnyvale, CA, USA) and outputs displayed on a digital oscilloscope. Electrical signals were digitized using an analog-to-digital converter (Digidata 1300 series; Axon Instruments), recorded and stored on a computer running Axoscope 9.0 software. Electrical recordings were made in the presence of nifedipine (1 μM) to reduce muscle contraction and maintain cellular impalements.
After fine dissection of the mucosa and submucosa small preparations (approximately 10 mm2) were pinned, with the luminal side of the circular muscle up, to Sylgard elastomer-coated bases of 35 mm polypropylene dishes (Corning Glass Works, Corning, NY, USA).
Cells were impaled with glass microelectrodes filled with 3 M KCl and having resistances between 80 and 120 MΩ. Transmembrane potentials were measured using a high input impedance amplifier (Axon Instruments/Molecular Devices Corp., Sunnyvale, CA, USA) and outputs displayed on a digital oscilloscope. Electrical signals were digitized using an analog-to-digital converter (Digidata 1300 series; Axon Instruments), recorded and stored on a computer running Axoscope 9.0 software. Electrical recordings were made in the presence of nifedipine (1 μM) to reduce muscle contraction and maintain cellular impalements.