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L, P, and Q type voltage‐dependent calcium channels in vascular myocytes
Author(s) -
Skott Ole,
Andreasen Ditte,
Friis Ulla G.,
Uhrenholt Torben R.,
Jensen Boye L.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a304-b
Subject(s) - myocyte , voltage dependent calcium channel , vascular smooth muscle , chemistry , l type calcium channel , endocrinology , blockade , immunolabeling , patch clamp , medicine , calcium , electrophysiology , biology , smooth muscle , receptor , immunohistochemistry
We examined whether P‐, Q‐, and L‐type calcium channels are expressed and contribute to calcium currents in vascular myocytes. Cav 2.1a (P‐type) and Cav 2.1b (Q‐type) mRNA were demonstrated by RT‐PCR in renal preglomerular vessels from rats and mice. Immunolabeling of A7r5 cells, renal cryosections, and freshly isolated renal vascular myocytes with anti‐Cav1.2 and anti‐Cav2.1 antibodies revealed expression of both channels in all myocytes. Whole‐cell patch clamp on single mouse preglomerular vascular myocytes showed that blockade of L‐type currents with calciseptine (20 nmol/L) inhibited 35.6 ± 3.9 % of the calcium current, blocking P‐type currents with Agatoxin IVA (10 nmol/L) led to 20.2 ± 3.0 % inhibition whereas 300 nmol/L of Agatoxin IVA (blocking P and Q‐type) inhibited 45.0 ± 7.3 %. In rat aortic smooth muscle cells (A7r5) blockade of L‐type channels resulted in 28.5 ± 6.1% inhibition, simultaneous blockade of L‐type and P‐type channels inhibited 58.0 ± 11.8%, and simultaneous inhibition of L‐, P‐, and Q‐type channels blocked 88.7±5.6% of the calcium current. We conclude that aortic and renal preglomerular smooth muscle cells co‐express L‐, P‐ and Q‐type Cav.