The resting potential of marginal cells in stria vascularis explants

In order to examine the intracellular potential of stria vascularis marginal cells (MCs) under direct visual control, a short-term organ culture of guinea pig stria vascularis (SV) was developed. The experimental conditions allowed exposure of the luminal surface of the SV to artificial endolymph or perilymph. Using conventional microelectrodes and inverted bright-field microscopy, impalement of MCs from the endolymphatic side through the luminal cell membrane was achieved. With artificial perilymph at the luminal side a small positivity at the cell surface and low negative intracellular potentials were recorded at room temperature (23 degrees C). The initial recording was -6.5 +/- 5.0 mV while the stable recording was -4.0 +/- 3.6 mV. Similar results were obtained at a bath temperature of 37 degrees C. Furthermore, subtotal exposure of the luminal cell surface to artificial endolymph did not result in a significant potential change.