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Catheterization of the Carotid Artery and Jugular Vein to Perform Hemodynamic Measures, Infusions and Blood Sampling in a Conscious Rat Model
Published on: January 30, 2015
A standing Na+ conductance in rat carotid body type I cells
1Institute for Cardiovascular Research, University of Leeds, UK.
Abstract:
Substitution of extracellular Na+ with N-methyl D-glucamine caused marked hyperpolarisation in rat isolated carotid body type I cells, suggesting the presence of a standing Na+ conductance. Choline substitution produced smaller hyperpolarisations, whilst Li+ was virtually without effect. This Na+ conductance was not blocked by amiloride, tetrodotoxin, Zn2+ or Gd3+ and did not arise from electrogenic Na-glucose co-transport, since substitution of glucose with sucrose could not mimic the effects of Na+ substitution. Hypoxia and acidosis did not modify the tonic Na+ influx. Our results suggest that Na+ influx provides a constant depolarising influence on type I cells which acts to shift membrane potential beyond that required for initiation of neurosecretion, an essential step in carotid body chemotransduction.
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