Objective: Nitric oxide(NO) is involved in neural signaling that is important to the physiologic and pathophysiologic activities of cochlea and vestibule. This study is to compare physiologic function of mammalian cochlea with that of chicken cochlea.
Methods: Using chemically modified carbon fiber microelectrode to measure qualitatively NO which was released from isolated cochlear neuron cluster of chicken in response to certain agonists, such as ATP, L-Arg and ACh. The presence of NO release is indicated by elevation of amplitude and lasting time of microelectric current.
Results: The results demonstrated that No releases stimulated by ACh and L-Arg were similar in amplitude but the lasting time stimulated by ACh was shorter than that of L-Aeg. Response to ATP, however, differred apparently in a manner which the amplitude was larger than that of ACh and L-Arg, whereas the lasting time approximated to that of L-Arg but longer than that of ACh. Before application of agonists, preapplication of L-NNA, a NOS antagonist no current changes could be monitored.
Conclusion: These data suggested that chicken cochlear ganglion can synthesize and release NO. The effective mechanism of the agonists and possible role of NO in the cochlea is discussed.