Analysis of the responses to acetylcholine in isolated supporting cells from the guinea-pig cochlea*
The whole cell patch clamp modes were developed to investigate the ionic channels of cellular membrane and to elucidate the signal transduction pathways from receptor to effector. The auditory sensory organ of mammals, the organ of Corti, is located on the basilar membrane. This organ consists of two types of sensory hair cells, outer and inner hair cells (OHC and IHC), and a surrounding network of various supporting cells, the largest part of the supporting cells is made of Deiters' cells (DCs) and Hensen's cells (HEs). By using whole cell patch clamp technique, the Acetylcholine (Ach) -induced current (IAch) in dissociated OHC of guinea-pig cochlea has been investigated. The aim of this presented study was to determine whether voltage-dependent currents exist in the supporting cells which are associated with the hair cells. Two types of supporting cells, DCs and HEs, were freshly isolated from guinea-pig cochlea. The current-voltage relations of the DCs was higher than the HEs, and the IAch in DCs was increased, but the IAch in HEs was not observed. Ach induced outward currents of DCs was increased by the concentration. The responses to Ach were suppressed by the muscarinic antagonist, atropine (10-6M), and the nicotinic antagonist, D-tubocrarine (10-6M). It suggests that the Ach receptor of DCs was both the muscarinic and nicotinic receptor. (Accepted on June 15, 1998) Kawasaki Igakkaishi 24(1 ) : 25-33, 1998
