Synaptic bodies and vesicles in the calix type synapse of chicken semicircular canal ampullae.

Calix afferent fibers generate depolarizing DC (direct current) and superimposed AC (alternating current) potentials in response to a vibrating stimulation of the hair bundle in an isolated preparation of a chicken semicircular canal ampulla. The wave form of the postsynaptic potential appears similar to the transduction potential of hair cells, which suggests electrical transmission in the calix type synapse. However, synaptic bodies and vesicles were found by EM observation instead of gap junctions in the hair cell presynaptic to the calix afferent. The number of synaptic body was 11-12/hair cell. These structures support chemical transmission in the calix type synapse.