Abstract
Cells in taste buds are closely packed, with little extracellular space. Tight junctions and other barriers further limit permeability and may result in buildup of extracellular K+ following action potentials. In many tissues, inwardly rectifying K channels such as the renal outer medullary K (ROMK) channel (also called Kir1.1 and derived from the Kcnj1 gene) help to redistribute K+. Using reverse-transcription polymerase chain reaction (RT-PCR), we defined ROMK splice variants in mouse kidney and report here the expression of a single one of these, ROMK2, in a subset of mouse taste cells. With quantitative (q)RT-PCR, we show the abundance of ROMK mRNA in taste buds is vallate > foliate > > palate > > fungiform. ROMK protein follows the same pattern of prevalence as mRNA, and is essentially undetectable by immunohistochemistry in fungiform taste buds. ROMK protein is localized to the apical tips of a subset of taste cells. Using tissues from PLCβ2-GFP and GAD1-GFP transgenic mice, we show that ROMK is not found in PLCβ2-expressing type II/receptor cells or in GAD1-expressing type III/presynaptic cells. Instead, ROMK is found, by single-cell RT-PCR and immunofluorescence, in most cells that are positive for the taste glial cell marker, Ectonucleotidase2. ROMK is precisely localized to the apical tips of these cells, at and above apical tight junctions. We propose that in taste buds, ROMK in type I/ glial-like cells may serve a homeostatic function, excreting excess K+ through the apical pore, and allowing excitable taste cells to maintain a hyperpolarized resting membrane potential.
| Original language | English |
|---|---|
| Pages (from-to) | 1-14 |
| Number of pages | 14 |
| Journal | Journal of Comparative Neurology |
| Volume | 517 |
| Issue number | 1 |
| DOIs | |
| State | Published - Oct 15 2009 |
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Keywords
- Acid taste
- Glia
- K transport
- kcnj1
- Kir1.1
ASJC Scopus subject areas
- Neuroscience(all)
Cite this
Inward rectifier channel, ROMK, is localized to the apical tips of glial-like cells in mouse taste buds. / Dvoryanchilov, Gennady; Sinclair, Michael S.; Perea-Martinez, Isabel; Wang, Tong; Chaudhari, Nirupa.
In: Journal of Comparative Neurology, Vol. 517, No. 1, 15.10.2009, p. 1-14.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Inward rectifier channel, ROMK, is localized to the apical tips of glial-like cells in mouse taste buds
AU - Dvoryanchilov, Gennady
AU - Sinclair, Michael S.
AU - Perea-Martinez, Isabel
AU - Wang, Tong
AU - Chaudhari, Nirupa
PY - 2009/10/15
Y1 - 2009/10/15
N2 - Cells in taste buds are closely packed, with little extracellular space. Tight junctions and other barriers further limit permeability and may result in buildup of extracellular K+ following action potentials. In many tissues, inwardly rectifying K channels such as the renal outer medullary K (ROMK) channel (also called Kir1.1 and derived from the Kcnj1 gene) help to redistribute K+. Using reverse-transcription polymerase chain reaction (RT-PCR), we defined ROMK splice variants in mouse kidney and report here the expression of a single one of these, ROMK2, in a subset of mouse taste cells. With quantitative (q)RT-PCR, we show the abundance of ROMK mRNA in taste buds is vallate > foliate > > palate > > fungiform. ROMK protein follows the same pattern of prevalence as mRNA, and is essentially undetectable by immunohistochemistry in fungiform taste buds. ROMK protein is localized to the apical tips of a subset of taste cells. Using tissues from PLCβ2-GFP and GAD1-GFP transgenic mice, we show that ROMK is not found in PLCβ2-expressing type II/receptor cells or in GAD1-expressing type III/presynaptic cells. Instead, ROMK is found, by single-cell RT-PCR and immunofluorescence, in most cells that are positive for the taste glial cell marker, Ectonucleotidase2. ROMK is precisely localized to the apical tips of these cells, at and above apical tight junctions. We propose that in taste buds, ROMK in type I/ glial-like cells may serve a homeostatic function, excreting excess K+ through the apical pore, and allowing excitable taste cells to maintain a hyperpolarized resting membrane potential.
AB - Cells in taste buds are closely packed, with little extracellular space. Tight junctions and other barriers further limit permeability and may result in buildup of extracellular K+ following action potentials. In many tissues, inwardly rectifying K channels such as the renal outer medullary K (ROMK) channel (also called Kir1.1 and derived from the Kcnj1 gene) help to redistribute K+. Using reverse-transcription polymerase chain reaction (RT-PCR), we defined ROMK splice variants in mouse kidney and report here the expression of a single one of these, ROMK2, in a subset of mouse taste cells. With quantitative (q)RT-PCR, we show the abundance of ROMK mRNA in taste buds is vallate > foliate > > palate > > fungiform. ROMK protein follows the same pattern of prevalence as mRNA, and is essentially undetectable by immunohistochemistry in fungiform taste buds. ROMK protein is localized to the apical tips of a subset of taste cells. Using tissues from PLCβ2-GFP and GAD1-GFP transgenic mice, we show that ROMK is not found in PLCβ2-expressing type II/receptor cells or in GAD1-expressing type III/presynaptic cells. Instead, ROMK is found, by single-cell RT-PCR and immunofluorescence, in most cells that are positive for the taste glial cell marker, Ectonucleotidase2. ROMK is precisely localized to the apical tips of these cells, at and above apical tight junctions. We propose that in taste buds, ROMK in type I/ glial-like cells may serve a homeostatic function, excreting excess K+ through the apical pore, and allowing excitable taste cells to maintain a hyperpolarized resting membrane potential.
KW - Acid taste
KW - Glia
KW - K transport
KW - kcnj1
KW - Kir1.1
UR - http://www.scopus.com/inward/record.url?scp=70349804450&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=70349804450&partnerID=8YFLogxK
U2 - 10.1002/cne.22152
DO - 10.1002/cne.22152
M3 - Article
C2 - 19708028
AN - SCOPUS:70349804450
VL - 517
SP - 1
EP - 14
JO - Journal of Comparative Neurology
JF - Journal of Comparative Neurology
SN - 0021-9967
IS - 1
ER -