Channel subunits in adult rat heart: Relation to functional K+ channels?

Dianne M. Barry, James Trimmer, John P. Merlie, Jeanne M. Nerbonne

Research output: Contribution to journalArticle

229 Citations (Scopus)

Abstract

Polyclonal antibodies against each of the K+ channel subunits (Kv1.2, Kv1.4, Kv1.5, Kv2.1, and Kv4.2) shown previously to be expressed in adult rat heart at the mRNA level were used to examine the distributions of these K+ channel subunits in adult rat atrial and ventricular membranes. Immunohistochemistry on isolated adult rat ventricular myocytes revealed strong labeling with the anti-Kv4.2 and anti-Kv1.2 antibodies. Although somewhat weaker (than with anti-Kv1.2 or anti-Kv4.2), positive staining was also observed with the anti-Kv1.5 and anti-Kv2.1 antibodies. Ventricular myocytes exposed to the anti-Kv1.4 antibody, in contrast, did not appear significantly different from background. Qualitatively similar results were obtained on isolated adult rat atrial myocytes. Western blots of atrial and ventricular membrane proteins confirmed the presence of Kv1.2, Kv1.5, Kv2.1, and Kv4.2 and revealed differences in the relative abundances of these subunits in the two membrane preparations. Kv4.2, for example, is more abundant in ventricular than in atrial membranes, whereas Kv1.2 and Kv2.1 are higher in atrial membranes; Kv1.5 levels are comparable in the two preparations. In contrast to these results, nothing was detected in Western blots of atrial or ventricular membrane proteins with the anti-Kv1.4 antibody at concentrations that revealed intense labeling of a 97-kD protein in adult rat brain membranes. A very faint band was detected at 97 kD in the atrial and ventricular preparations when the anti-Kv1.4 antibody was used at a 5- to 10-fold higher concentration. The simplest interpretation of these results is that Kv1.4 is not an abundant protein in adult rat atrial or ventricular myocytes. Therefore, it seems unlikely that Kv1.4 plays an important role in the formation of functional depolarization-activated K+ channels in these cells. The relation(s) between the (other four) K+ channel subunits and the depolarization-activated K+ channels identified electrophysiologically in adult rat atrial and ventricular myocytes is discussed in the present study.

Original languageEnglish (US)
Pages (from-to)361-369
Number of pages9
JournalCirculation Research
Volume77
Issue number2
StatePublished - Aug 1995
Externally publishedYes

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Muscle Cells
Anti-Idiotypic Antibodies
Membranes
Kv1.2 Potassium Channel
Membrane Proteins
Western Blotting
Proteins
Immunohistochemistry
Staining and Labeling
Messenger RNA
Antibodies
Brain

Keywords

  • Cardiac myocytes
  • Depolarization-activated K channels
  • Shab
  • Shaker
  • Shal

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

Cite this

Barry, D. M., Trimmer, J., Merlie, J. P., & Nerbonne, J. M. (1995). Channel subunits in adult rat heart: Relation to functional K+ channels? Circulation Research, 77(2), 361-369.

Channel subunits in adult rat heart : Relation to functional K+ channels? / Barry, Dianne M.; Trimmer, James; Merlie, John P.; Nerbonne, Jeanne M.

In: Circulation Research, Vol. 77, No. 2, 08.1995, p. 361-369.

Research output: Contribution to journalArticle

Barry, DM, Trimmer, J, Merlie, JP & Nerbonne, JM 1995, 'Channel subunits in adult rat heart: Relation to functional K+ channels?', Circulation Research, vol. 77, no. 2, pp. 361-369.
Barry DM, Trimmer J, Merlie JP, Nerbonne JM. Channel subunits in adult rat heart: Relation to functional K+ channels? Circulation Research. 1995 Aug;77(2):361-369.
Barry, Dianne M. ; Trimmer, James ; Merlie, John P. ; Nerbonne, Jeanne M. / Channel subunits in adult rat heart : Relation to functional K+ channels?. In: Circulation Research. 1995 ; Vol. 77, No. 2. pp. 361-369.
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