Basolateral amiloride-sensitive Na+ transport pathway in rat tongue epithelium
Mierson, S; Olson, MM; Tietz, AE
| HERO ID | 4947506 |
|---|---|
| In Press | No |
| Year | 1996 |
| Title | Basolateral amiloride-sensitive Na+ transport pathway in rat tongue epithelium |
| Authors | Mierson, S; Olson, MM; Tietz, AE |
| Journal | Journal of Neurophysiology |
| Volume | 76 |
| Issue | 2 |
| Page Numbers | 1297-1309 |
| Abstract | 1. Experiments were conducted to test for the presence of basolateral Na+ channels in the rat lingual epithelium. Researchers have proposed a model in which some lingual taste cells have Na+ channels in the basolateral membrane. That model is designed to account for the portion of the neural taste response and the portion of the transepithelial short-circuit current (I-sc) in vitro that are insensitive to mucosal amiloride; some Na+ would diffuse across the tight junction into the cell via this lateral pathway, and would be transported out of the cell by Na+ pumps in the basal membrane. The model could also account for the differential effect of mucosal amiloride on Na+ salts of various anions, in which the neural taste responses to Na+ salts with anions larger than Cl- are more sensitive to mucosal amiloride than is the taste response to NaCl. <br> <br>2. Voltage-clamp data were obtained from an in vitro preparation of the anterior-dorsal rat tongue epithelium in which the connective tissue was removed by enzyme digestion. I-sc in a modified Ussing chamber was reduced by amiloride in the submucosal solution. <br> <br>3. The pattern of sensitivity to submucosal amiloride differed in several respects from the pattern for mucosal amiloride. The inhibition constant (K-1) was 52 mu M amiloride concentration, higher than for the apical amiloride-sensitive Na+ channel. The selectivity for Na+ over K+ was much less than for the response to mucosal amiloride; with 0.5 M NaCl or KCI on the mucosal side, the ratio of inhibition for the NaCl response to inhibition for the KCl response varied between 1 and 3. <br> <br>4. As the concentration of NaCl in the mucosal solution was varied, submucosal amiloride caused little inhibition of I-sc for mucosal NaCl below isosmotic concentration, with the percent inhibi tion increasing as mucosal salt concentration increased. With 0.5 M sodium gluconate in the mucosal solution, there was very little inhibition due to submucosal amiloride. <br> <br>5. The results support the presence of amiloride-sensitive Na+ channels in the basolateral membranes of the dorsal tongue epithelium in rat, and are consistent with the proposed model in which these channels are present in taste cells. |
| Wosid | WOS:A1996VD97200049 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |