Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2847480 | Respiratory Physiology & Neurobiology | 2011 | 8 Pages |
Abstract
Carotid body chemoreceptors transduce a decrease in arterial oxygen tension into increased sinus nerve action potential (AP) activity which undergoes a maturational increase in the post-natal period. MaxiK-channels channels are proposed to play a major role in organ function based on their maturation-dependent expression in glomus cells and inhibition by acute hypoxia. To better resolve the role of this channel, single-unit AP activity of rat chemoreceptor neurons was recorded, in vitro, during a progressive decrease in oxygen from normoxia (â¼150Â Torr) to moderate hypoxia (â¼60Â Torr). Blockade of MaxiK channels with charybdotoxin (100Â nM) in both older (P16-P18) and younger (P2-P3) animals resulted in no significant change in AP activity, but increased nerve conduction speed in the older animals. In dissociated glomus cells, charybdotoxin slightly enhanced the intracellular calcium response to acute hypoxia at both ages. We conclude that MaxiK channels play little or no role in mediating the response to acute, moderate hypoxia, either in the newborn or older animal.
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Authors
David F. Donnelly, Insook Kim, Dong Yang, John L. Carroll,