Initially, type I taste bud cells were suggested to be responsible for tasting low concentrations of salt, however a subset of type II taste bud cells are now thought to be responsible (Nomura et al. 2020). The identity of salt-tasting cells remains a subject of current research. The ability to taste low concentrations of salt is at least partially due to an amiloride-sensitive sodium channel believed to be an SCNN channel (ENaC channel). SCNN complexes contain the pore-forming subunit SCNN1A or SCNN1D, and the modulatory subunits SCNN1B and SCNN1G, all of which have been detected in human taste buds (Rossier et al. 2004, Stähler et al. 2008). Knockout of SCNN1A in mice abolished amiloride-sensitive salt taste and attraction to low concentrations of salt, however SCNN1B and SCNN1G do not colocalize with SCNN1A in taste cells of mice (Lossow et al. 2020), raising the question of the subunit composition of the SCNN complex. SCNN1D is present in human taste cells but not in mouse taste cells.In humans, a SCNN channel containing SCNN1A or SCNN1D located in the plasma membrane is believed to transport sodium ions from the extracellular region into the cytosol, resulting in depolarization that causes CALHM1:CALHM3 channels to open and release ATP, a neurotransmitter, from the cytosol to the extracellular region.
Harty, TP, Choi, JS, Estacion, M, Dib-Hajj, SD, Waxman, SG, Tyrrell, L
Bigiani, A
Roper, SD
Meyerhof, W, Lossow, K, Behrens, M, Hermans-Borgmeyer, I
Iwata, K, Ishidate, F, Taruno, A, Nomura, K, Nakanishi, M
Rossier, O, Huque, T, Spielman, AI, Medrano, JF, Feldman, RS, Cao, J, Brand, JG, le Coutre, J
Raab, B, Hofmann, T, Neumann, K, Meyerhof, W, Behrens, M, Demgensky, S, Stähler, F, Riedel, K, Raguse, JD, Täubert, A, Dunkel, A
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