Electrical excitability of taste cells. Mechanisms and possible physiological significance

Neuronal, muscle and some endocrine cells are electrically excitable. While in muscle and endocrine cells AP stimulates and synchronizes intracellular processes, neurons employ action potentials (APs) to govern discontinuous synapses located distantly. Meanwhile, such axonless sensory cells as photo...

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Published in:Biochemistry (Moscow). Supplement series A, Membrane and cell biology Membrane and cell biology, 2012-04, Vol.6 (2), p.169-185
Main Authors: Romanov, R. A., Rogachevskaja, O. A., Bystrova, M. F., Kolesnikov, S. S.
Format: Article
Language:English
Subjects:
Biochemistry
Biomedical and Life Sciences
Cell Biology
Cellular biology
Ions
Life Sciences
Neurotransmitters
Reviews
Taste
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Summary:Neuronal, muscle and some endocrine cells are electrically excitable. While in muscle and endocrine cells AP stimulates and synchronizes intracellular processes, neurons employ action potentials (APs) to govern discontinuous synapses located distantly. Meanwhile, such axonless sensory cells as photoreceptors and hair cells exemplify afferent output, which is not driven by APs; instead, gradual receptor potentials elicited by sensory stimuli control the release of afferent neurotransmitter glutamate. Mammalian taste cells of the type II and type III are electrically excitable and respond to stimulation by firing APs. Since taste cells also have no axons, physiological significance of the electrical excitability for taste transduction and encoding sensory information is unclear. Perhaps, AP facilitates transmitter release, ATP in type II cells and 5-HT in type III cells, although via different mechanisms. The ATP release is mediated by connexin hemichannels, does not require a Ca 2+ trigger, and largely gated by membrane voltage. 5-HT secretion is driven by intracellular Ca 2+ and involves VG Ca 2+ channels. Here, we discuss ionic mechanisms of excitability of taste cells and speculate on a likely role of APs in mediating their afferent output.
ISSN:1990-7478
1990-7494
DOI:10.1134/S1990747812010126