The Kv2.2 α subunit contributes to delayed rectifier K+ currents in myocytes from rabbit corpus cavernosum

John Malysz, Gianrico Farrugia, Yijun Ou, Joseph H. Szurszewski, Ajay Nehra, Simon J. Gibbons

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

K+ currents are known to regulate the excitability of corpus cavernosum myocytes and therefore to play a role in the control of penile erection and detumescence. We used electrophysiology and molecular cloning techniques to identify ion channel proteins that contribute to K+ currents in rabbit cavernosal myocytes. Currents were recorded from freshly isolated myocytes using whole-cell patch clamp techniques. Cavernosal myocytes expressed a delayed rectifier voltage-gated K+ current that appeared to contribute to the resting membrane potential. This voltage-gated K+ (Kv) current was inhibited by the nonselective compounds 4-aminopyridine (1-10 mM), (+)-fenfluramine (10 μM-1 mM), and Grammostola spatulata venom (1:100) in a dose-dependent and reversible fashion. Hanatoxin-1 (1 μM), a selective Kv2 channel inhibitor, partially inhibited the current, but α-dendrotoxin (200 nM), a Kv1 channel blocker, had no effect. The nucleotide sequence of K+ channel subunits was determined by polymerase chain reaction-based cloning techniques using RNA derived from cavernosal muscle strips and single identified myocytes. Molecular cloning, techniques identified the full-length sequence of the rabbit ortholog of the Kv2.2 α subunit. This sequence contains 911 amino acid residues and is 92% identical to the recently revised human Kv2.2 sequence. Identified cavernosal myocytes of the type used in physiological recordings expressed Kv2.2 messenger RNA. We conclude that Kv2.2 α subunits contribute to whole-cell currents in rabbit cavernosal myocytes. Further, Kv currents play a role in regulating membrane potential and hence excitability in rabbit cavernosal myocytes.

Original languageEnglish (US)
Pages (from-to)899-910
Number of pages12
JournalJournal of Andrology
Volume23
Issue number6
StatePublished - Nov 2002

Keywords

  • Molecular cloning
  • Patch clamp techniques
  • Penile erection
  • Potassium channels
  • Smooth muscle

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Reproductive Medicine
  • Endocrinology
  • Urology

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    Malysz, J., Farrugia, G., Ou, Y., Szurszewski, J. H., Nehra, A., & Gibbons, S. J. (2002). The Kv2.2 α subunit contributes to delayed rectifier K+ currents in myocytes from rabbit corpus cavernosum. Journal of Andrology, 23(6), 899-910.