AUDITORY AND VESTIBULAR SYSTEMSDopamine modulates sodium currents in cochlear spiral ganglion neuronsSun, Wei; Salvi, Richard J.CA Author Information Hearing Research Lab, 215 Parker Hall, SUNY University at Buffalo, Buffalo, NY 14214, USA CACorresponding Author Received 5 December 2000; accepted 9 January 2001 Neuroreport 12(4):p 803-807, March 26, 2001. Buy Abstract Lateral olivocochlear (LOC) efferent neurons, putatively dopaminergic, synapse on afferent dendrites of type I spiral ganglion neurons (SGNs) in the cochlea and depress their activity. To investigate the underlying mechanisms, whole-cell patch clamp recordings were obtained from mouse SGNs. Dopamine (DA), and D1-like (D1, D5) and D2-like (D2, D3 and D4) receptor agonists, reduced AP amplitude and induced a slow transient depolarization. Under voltage clamp, D1-like and D2-like agonists induced a dose-dependent inward current that was reversibly blocked by their receptor antagonists. The inward current was blocked by tetrodotoxin (TTX), implicating Na+ channels. The reduction of AP amplitude and voltage-gated Na+ current by DA and DA agonists provides a mechanism for suppressing spike activity in type I afferent neurons. © 2001 Lippincott Williams & Wilkins, Inc.
