Reduced vascular smooth muscle BK channel current underlies heart failure-induced vasoconstriction in mice.
FASEB J
; 27(5): 1859-67, 2013 May.
Article
in En
| MEDLINE
| ID: mdl-23325318
ABSTRACT
Excessively increased peripheral vasoconstriction is a hallmark of heart failure (HF). Here, we show that in mice with systolic HF post-myocardial infarction, the myogenic tone of third-order mesenteric resistance vessels is increased, the vascular smooth muscle (VSM) membrane potential is depolarized by ~20 mV, and vessel wall intracellular [Ca(2+)] is elevated relative to that in sham-operated control mice. Despite the increased [Ca(2+)], the frequency and amplitude of spontaneous transient outward currents (STOCs), mediated by large conductance, Ca(2+)-activated BK channels, were reduced by nearly 80% (P<0.01) and 25% (P<0.05), respectively, in HF. The expression of the BK α and ß1 subunits was reduced in HF mice compared to controls (65 and 82% lower, respectively, P<0.01). Consistent with the importance of a reduction in BK channel expression and function in mediating the HF-induced increase in myogenic tone are two further findings:
a blunting of paxilline-induced increase in myogenic tone in HF mice compared to controls (0.9 vs. 10.9%, respectively), and that HF does not alter the increased myogenic tone of BK ß1-null mice. These findings identify electrical dysregulation within VSM, specifically the reduction of BK currents, as a key molecular mechanism sensitizing resistance vessels to pressure-induced vasoconstriction in systolic HF.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Vasoconstriction
/
Large-Conductance Calcium-Activated Potassium Channels
/
Heart Failure
Type of study:
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
FASEB J
Journal subject:
BIOLOGIA
/
FISIOLOGIA
Year:
2013
Type:
Article
Affiliation country:
United States