Turnover, membrane insertion, and degradation of sodium channels in rabbit urinary bladder.
Noise analysis of rabbit bladder revealed two components: Lorentzian noise, arising from interaction of amiloride with the Na+ channel, and flicker noise (l/f, where f is frequency), as in other biological membranes. Hydrostatic pressure, which causes exchange between intracellular vesicular membrane and apical membrane, increases the number but not the single-channel current of the amiloride-sensitive channels. Flicker noise arises from degraded channels that have lost amiloride sensitivity and Na+ to K+ selectivity. The degraded channels were selectively removed by washing the mucosal surface. These results imply channel turnover by intracellular synthesis, transfer from vesicular to apical membrane, degradation, and elimination.
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D003594:Cytoplasmic Granules / Q000378:metabolism; D004848:Epithelium / Q000502:physiology; D011817:Rabbits; D012964:Sodium / Q000378:metabolism*; D001743:Urinary Bladder / Q000378:metabolism*
D000584:Amiloride; D012964:Sodium