Taste cells with synapses in rat circumvallate papillae display SNAP-25-like immunoreactivity

SNAP-25 is a 25 kDa protein believed to be involved in the processes of mem brane fusion and exocytosis associated with neurotransmitter release. In th e present study we present evidence that SNAP-25-like immunoreactivity can be used as a marker for taste cells with synapses in rat circumvallate papi llae. SNAP-25 immunoreactivity is present in most intragemmal nerve process es and a small subset of taste cells. Intense immunoreactivity is associate d with the nerve plexus located below the base of the taste bud. Of a total of 87 taste cells with synapses onto nerve processes, 80 of the presynapti c taste cells had SNAP-25 immunoreactivity. The association of SNAP-25 immu noreactivity with taste cells possessing synapses suggests that these cells may be gustatory receptor cells. Because this SNAP-25 antibody can label t aste cells with synapses, it may also serve as a useful tool for future stu dies correlating structure with function in the taste bud. J. Comp. Neurol. 424:205-215, 2000. (C) 2000 Wiley-Liss, Inc.