Single Taste Stimuli Elicit Either Increases or Decreases in Intracellular Calcium in Isolated Catfish Taste Cells |
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Authors: | MM Zviman D Restrepo JH Teeter |
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Institution: | (1) Monell Chemical Senses Center, 3500 Market St., Philadelphia, PA 19104, US;(2) Department of Physiology, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-3308, US |
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Abstract: | Taste cells are specialized epithelial cells that respond to stimulation with release of neurotransmitters onto afferent nerves
that innervate taste buds. In analogy to neurotransmitter release in other cells, it is expected that neurotransmitter release
in taste cells is dependent on an increase in intracellular Ca2+ (Ca2+]
i
). We have studied changes in Ca2+]
i
elicited by the taste stimuli l- and d-arginine in isolated taste cells from the channel catfish (Ictalurus punctatus). In a sample of 119 cells, we found 15 cells responding to l-arginine, and 12 cells responding to d-arginine with an increase in Ca2+]
i
. The response to l-arginine was inhibited by equimolar d-arginine in cells where d-arginine alone did not cause a change in Ca2+]
i
, which is consistent with mediation of this response by a previously characterized l-arginine-gated nonspecific cation channel antagonized by d-arginine 31]. However, we also found that these taste stimuli elicited decreases in Ca2+]
i
in substantial number of cells (6 for l-Arg, and 2 for d-Arg, n= 119). These observations suggest that stimulation of taste cells with sapid stimuli may result in simultaneous excitation
and inhibition of different taste cells within the taste bud, which could be involved in local processing of the taste signal.
Received: 25 May 1995/Revised: 29 September 1995 |
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Keywords: | : Catfish — Taste — Receptor — Calcium — Amino acids |
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