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Norepinephrine is coreleased with serotonin in mouse taste buds
Yijen A Huang1, Yutaka Maruyama, Stephen D Roper
1Department of Physiology and Biophysics, and Program in Neuroscience, University of Miami School of Medicine, Miami, Florida 33136, USA.
Summary
Norepinephrine (NE) is released from taste buds when stimulated, originating specifically from presynaptic (type III) cells, which also secrete serotonin (5-HT). Some type III cells corelease NE and 5-HT.
Area of Science:
- Neuroscience
- Taste receptor cell biology
Background:
- Adenosine triphosphate (ATP) and serotonin (5-HT) are known taste bud neurotransmitters.
- Norepinephrine (NE) has been proposed as a taste bud neurotransmitter, but its release stimulus and cellular origin were unknown.
Purpose of the Study:
- To determine the stimulus for NE release in taste buds.
- To identify the specific taste cells responsible for NE secretion.
Main Methods:
- Utilized Chinese hamster ovary (CHO) cells transfected with alpha(1A) adrenoceptors as NE biosensors.
- Stimulated isolated mouse taste buds and cells with KCl and taste compounds, detecting NE release via fura-2 imaging.
- Used dual biosensors to assess co-release of 5-HT and NE from individual cells.
Main Results:
- Taste buds released NE when stimulated by KCl or taste compounds, detected by NE biosensors.
- NE release was confirmed to originate exclusively from presynaptic (type III) taste cells, not receptor (type II) cells.
- All presynaptic cells secreted 5-HT, with 33% also coreleasing NE.
Conclusions:
- Taste bud cells, specifically presynaptic (type III) cells, secrete norepinephrine (NE) upon stimulation.
- NE release from type III cells is calcium-dependent and can occur concurrently with 5-HT secretion.
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