Vascular actions of C-type natriuretic peptide in isolated porcine coronary arteries and coronary vascular smooth muscle cells.
C-type natriuretic (CNP) caused concentration-dependent relaxations in porcine coronary arteries with a maximal relaxation (10(-6)M) of 46%. Relaxations to CNP in isolated coronary arteries were significantly attenuated with potassium channel antagonists charybdotoxin (10(-7)M) and glibenclamide (10(-7)M). Membrane potential and K+ currents were measured in enzymatically dissociated smooth muscle cells from porcine coronary arteries with patch-clamp techniques in a whole-cell mode (n = 5). CNP caused K+ channel activation and membrane hyperpolarization in a dose-dependent manner. This hyperpolarization was markedly suppressed by the potassium channel inhibitor tetraethylammonium (TEA, 5 mM). These results demonstrate that CNP relaxes porcine coronary arterial smooth muscle by hyperpolarization of vascular smooth muscle through potassium channel stimulation.
Wei
C M
CM
Cardiorenal Research Laboratory, Mayo Clinic and Foundation, Rochester, MN 55905.
Hu
S
S
Miller
V M
VM
Burnett
J C
JC
D000818:Animals; D001158:Arteries / Q000187:drug effects* / Q000502:physiology; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D003331:Coronary Vessels / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D020098:Natriuretic Peptide, C-Type; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology; D011506:Proteins / Q000494:pharmacology*; D013552:Swine
D015221:Potassium Channels; D011506:Proteins; D020098:Natriuretic Peptide, C-Type; D009320:Atrial Natriuretic Factor