Mouse taste buds use serotonin as a neurotransmitter.
Synapses between gustatory receptor cells and primary sensory afferent fibers transmit the output signal from taste buds to the CNS. Several transmitter candidates have been proposed for these synapses, including serotonin (5-HT), glutamate, acetylcholine, ATP, peptides, and others, but, to date, none has been unambiguously identified. We used Chinese hamster ovary cells stably expressing 5-HT2C receptors as biodetectors to monitor 5-HT release from taste buds. When taste buds were depolarized with KCl or stimulated with bitter, sweet, or sour (acid) tastants, serotonin was released. KCl- and acid-induced 5-HT release, but not release attributable to sweet or bitter stimulation, required Ca2+ influx. In contrast, 5-HT release evoked by sweet and bitter stimulation seemed to be triggered by intracellular Ca2+ release. These experiments strongly implicate serotonin as a taste bud neurotransmitter and reveal unexpected transmitter release mechanisms.
Huang
Yi-Jen
YJ
Department of Physiology and Biophysics, University of Miami School of Medicine, Miami, Florida 33136, USA.
Maruyama
Yutaka
Y
Lu
Kuo-Shyan
KS
Pereira
Elizabeth
E
Plonsky
Ilya
I
Baur
John E
JE
Wu
Dianqing
D
Roper
Stephen D
SD
D000255:Adenosine Triphosphate / Q000502:physiology; D000818:Animals; D015374:Biosensing Techniques; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D066298:In Vitro Techniques; D008803:Mianserin / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D044405:Receptor, Serotonin, 5-HT2C / Q000502:physiology; D012701:Serotonin / Q000378:metabolism / Q000502:physiology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D013650:Taste Buds / Q000378:metabolism / Q000502:physiology*
D044405:Receptor, Serotonin, 5-HT2C; D012702:Serotonin Antagonists; D008803:Mianserin; D012701:Serotonin; D000255:Adenosine Triphosphate; D002118:Calcium