Localization of cholinergic and purinergic receptors on outer hair cells isolated from the guinea-pig cochlea

摘要: Acetylcholine (ACh) and adenosine 59-triphosphate (ATP) are shown to act in opposing fashion on guinea-pig cochlear outer hair cells (OHCS) via receptors localized within different fluid compartments of the organ Corti. The cholinergic (efferent) at basal (perilymphatic) region these activated a rapidly desensitizing hyperpolarizing K + current. In contrast, purinergic were apical (endolymphatic) surface OHCS depolarizing nonselective cation current which exhibited inward rectification lacked desensitization. Localization was determined by using whole-cell patch-clamp, recording onset latencies response amplitudes pulses either ACh or ATP pressure-applied selected sites along length isolated OHCS. Under voltage-clamp —60 mV, largest ACh-induced (outward) currents recorded when directed cells. Conversely, maximum (inward) obtained toward Onset increased from minimum approximately 10 ms for as drug pipette moved away optimal sites. antagonized amiloride dose-dependent manner with D 400 uM. localization P 2 -type purinoceptors endolymphatic suggests that mediates humoral modulation mechanoelectrical transduction process.