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- Title
Descending vasa recta pericytes express voltage operated Na<sup>+</sup> conductance in the rat.
- Authors
Zhong Zhang; Chunhua Cao; Whaseon Lee-Kwon; Pallone, Thomas L.
- Abstract
We studied the properties of a voltage-operated Na+ conductance in descending vasa recta (DVR) pericytes isolated from the renal outer medulla. Whole-cell patch-clamp recordings revealed a depolarization-induced, rapidly activating and rapidly inactivating inward current that was abolished by removal of Na+ but not Ca+ from the extracellular buffer. The Na+ current ( INa) is highly sensitive to tetrodotoxin . At high concentrations, mibefradil (10 μ m) and Ni+ (1 m m) blocked INa. INa was insensitive to nifedipine (10 μ m). The L-type Ca+ channel activator FPL-64176 induced a slowly activating/inactivating inward current that was abolished by nifedipine. Depolarization to membrane potentials between 0 and 30 mV induced inactivation with a time constant of ∼1 ms. Repolarization to membrane potentials between −90 and −120 mV induced recovery from inactivation with a time constant of ∼11 ms. Half-maximal activation and inactivation occurred at −23.9 and −66.1 mV, respectively, with slope factors of 4.8 and 9.5 mV, respectively. The Na+ channel activator, veratridine (100 μ m), reduced peak inward INa and prevented inactivation. We conclude that a TTX-sensitive voltage-operated Na+ conductance, with properties similar to that in other smooth muscle cells, is expressed by DVR pericytes.
- Subjects
MEDULLA oblongata; NEURAL conduction; SODIUM; RATS; CELLS
- Publication
Journal of Physiology, 2005, Vol 567, Issue 2, p445
- ISSN
0022-3751
- Publication type
Article
- DOI
10.1113/jphysiol.2005.091538