Ca2+-Activated K+-Channels from Isolated Type I Carotid Body Cells of the Neonatal Rat

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Conference Proceeding

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Over the past five years, the patch-clamp technique has been applied to type I cells isolated from carotid bodies of rats and rabbits (e.g. Duchen et al., 1988; Lopez-Barneo et al., 1988; Delpiano & Hescheler, 1989; Peers, 1990a; Stea & Nurse, 1991). Our previous studies, using type I cells from rats (approximately 10 days old) have shown that whole-cell K+ currents can be subdivided into two types; a Ca2+-activated, charybdotoxin-sensitive current, IKCa, and a Ca2+-independent, voltage-gated current, IKV (Peers, 1990a,b). Of these, IKCa can be inhibited by chemostimuli such as hypoxia (Peers, 1990b), acidity (Peers, 1990a; Peers and Green, 1991) or the respiratory stimulant doxapram (Peers, 1991). Here, we describe the properties of the single Ca2+-activated K+ channels which underlie the macroscopic IKCa, and show that doxapram can inhibit this channel without the involvement of a second messenger system.


Presented at the 12th International Meeting of the International Society of Arterial Chemoreception on Chemoreceptors and Chemoreflexes in Health and Disease, Dublin, Ireland.