AUDITORY AND VESTIBULAR SYSTEMSActivation of metabotropic B receptors">GABAB receptors inhibited glutamate responses in spiral ganglion neurons of miceLin, Xi1,2; Chen, Shanping1; Chen, Ping1Author Information 1Department of Cell and Molecular Biology, House Ear Institute, 2100 West Third Street, Los Angeles, CA 90057, USA 2Corresponding Author: Xi Lin Acknowledgements: This project was supported in part by a grant from the Hedco Foundation. We thank Dr Karen Berliner for valuable suggestions made for this manuscript. Received 6 January 2000; accepted 19 January 2000 NeuroReport: April 7, 2000 - Volume 11 - Issue 5 - p 957-961 Buy Abstract The lateral olivocochlear efferent (LOC) fibers form axodendritic synapses with auditory nerve dendrites synapsing on inner hair cells to affect postsynaptic responses. GABA is one of the primary transmitters used by the LOC efferent. However, the molecular nature and developmental expression of the GABA receptors in spiral ganglion (SG) neurons are poorly understood. We have identified the B receptors">GABAB receptors in SG neurons of mice by pharmacological criteria and polymerase chain reaction (PCR) detection. Applications of GABA or baclofen increased intracellular Ca2+ concentrations and inhibited glutamate responses. The responses were blocked by saclofen, but not by bicuculline. Relative-quantitative PCR showed that B receptors">GABAB receptors were expressed prenatally, and their levels did not change significantly during the maturation of SG neurons. © 2000 Lippincott Williams & Wilkins, Inc.