Expression and function of native potassium channel (Kvα1) subunits in terminal arterioles of rabbit

A. Cheong, A. M. Dedman, D. J. Beech*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


1. In this study we investigated the expression and function of the KVα1 subfamily of voltage-gated K+ channels in terminal arterioles from rabbit cerebral circulation. 2. K+ current was measured from smooth muscle cells within intact freshly isolated arteriolar fragments. Current activated on depolarisation positive of about -45 mV and a large fraction of this current was blocked by 3,4-diaminopyridine (3,4-DAP) or 4-aminopyridine (4-AP), inhibitors of KV channels. Expression of cRNA encoding KV1.6 in Xenopus oocytes also generated a 4-AP-sensitive K+ current with a threshold for activation near -45 mV. 3. Immunofluorescence labelling revealed KV1.2 to be specifically localised to endothelial cells, and KV1.5 and KV1.6 to plasma membranes of smooth muscle cells. 4. KV channel current in arteriolar fragments was blocked by correolide (which is specific for the KVα1 family of KV channels) but was resistant to recombinant agitoxin-2 (rAgTX2; which inhibits KV1.6 but not KV1.5). Heterologously expressed KV2.1 was resistant to correolide, and KV1.6 was blocked by rAgTX2. 5. Arterioles that were mildly preconstricted and depolarised by 0.1-0.3 nM endothelin-1 constricted further in response to 3,4-DAP, 4-AP or correolide, but not to rAgTX2. 6. We suggest that KVα1 channels are expressed in smooth muscle cells of terminal arterioles, underlie a major part of the voltage-dependent K+ current, and have a physiological function to oppose vasoconstriction. KVα1 complexes without KV1.5 appear to be uncommon.

Original languageEnglish
Pages (from-to)691-700
Number of pages10
JournalJournal of Physiology
Issue number3
Publication statusPublished - 1 Aug 2001


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