Glutamate and carnosine in the vestibular system of the frog.

We demonstrate that both glutamate-like and carnosine-like immunoreactivities are present in hair cells and in fibers of the vestibular organ of the frog inner ear. Comparison of the two immunoreactivity patterns indicates that glutamate and carnosine might be colocalized in some hair cells. The presence of glutamate-like immunoreactivity in hair cells is consistent with biochemical and pharmacological data indicating glutamate as the excitatory neurotransmitter in these sensory receptors. There is also evidence that carnosine might have a neuromodulatory function.