October 1, 1988AJP Heart and Circulatory Physiology
Cyclic AMP modulates Ca-activated K channel in cultured smooth muscle cells of rat aortas
Population
Cultured smooth muscle cells of rat aortas
Comparison
Extracellular application of isoproterenol (10… vs Baseline/control conditions
Design
Preclinical
Authors
Discussion
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Member takes
Implication
Links beta-adrenergic signaling to vascular KCa activity in rats; leaves open human translation.
Key Points
- To determine how cyclic AMP and protein kinase A modulate calcium-activated potassium channel activity in cultured rat aortic smooth muscle cells.
- Recorded single calcium-activated potassium currents using cell-attached and inside-out patch-clamp techniques on cultured rat aortic smooth muscle cells.
- Tested channel kinetics and open probability during exposure to isoproterenol, propranolol, forskolin, dibutyryl cAMP, and purified cAMP-dependent protein kinase.
- Extracellular isoproterenol, forskolin, and dibutyryl cAMP increased channel open probability without altering unit conductance or channel density, an effect blocked by propranolol.
- Application of active cAMP-dependent protein kinase in inside-out patches increased channel sensitivity to intracellular calcium and significantly reduced the mean closed time between bursting openings.
Structured PICO
P
Population
Cultured smooth muscle cells of rat aortas
I
Intervention
Extracellular application of isoproterenol (10(-5) M), forskolin (10(-5) M), dibutyryl cAMP (10(-4) M), or activated cAMP-dependent protein kinase (A kinase)
C
Comparator
Baseline/control conditions
O
Outcome
Single Ca-activated K current (IK(Ca)) and probability of channel openings (Po)surrogate
cAMP-dependent phosphorylation increases the probability of opening of Ca-activated K channels in rat aortic smooth muscle cells.
Cite This Study
Sadoshima et al. (1988) studied this question.