Hypertension is a clinical syndrome characterized by increased vascular tone. However, the molecular mechanisms underlying vascular dysfunction during acquired hypertension remain unresolved. Localized intracellular Ca2+ release events through ryanodine receptors (Ca2+ sparks) in the sarcoplasmic reticulum are tightly coupled to the activation of large-conductance, Ca2+-activated K+ (BK) channels to provide a hyperpolarizing influence that opposes vasoconstriction. In this study we tested the hypothesis that a reduction in Ca2+ spark–BK channel coupling underlies vascular smooth muscle dysfunction during acquired hypertension. We found that in hypertension, expression of the β1 subunit was decreased relative to the pore-forming α subunit of the BK channel. Consequently, the BK channels were functionally uncoupled from Ca2+ sparks. Consistent with this, the contribution of BK channels to vascular tone was reduced during hypertension. We conclude that downregulation of the β1 subunit of the BK channel contributes to vascular dysfunction in hypertension. These results support the novel concept that changes in BK channel subunit composition regulate arterial smooth muscle function.
Gregory C. Amberg, Adrian D. Bonev, Charles F. Rossow, Mark T. Nelson, Luis F. Santana
Usage data is cumulative from April 2023 through April 2024.
Usage | JCI | PMC |
---|---|---|
Text version | 750 | 76 |
100 | 17 | |
Figure | 127 | 8 |
Citation downloads | 18 | 0 |
Totals | 995 | 101 |
Total Views | 1,096 |
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.