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Abnormal coronary function in mice deficient in alpha1H T-type Ca2+ channels.
Chien-Chang Chen1, Kathryn G Lamping, Daniel W Nuno
1Howard Hughes Medical Institute, University of Iowa, Iowa City, IA 52242, USA.
Science (New York, N.Y.)
|November 25, 2003
Summary
Calcium ion influx via alpha1H T-type channels is crucial for coronary artery relaxation. Mice lacking these channels exhibit constricted arteries, highlighting their role in vascular tone regulation.
Area of Science:
- Cardiovascular physiology
- Ion channel function
Background:
- Voltage-gated calcium channels regulate vascular tone.
- The specific role of T-type Ca2+ channels in coronary arteries is not well understood.
Purpose of the Study:
- To investigate the function of alpha1H T-type Ca2+ channels in coronary artery regulation.
- To determine the necessity of alpha1H T-type Ca2+ channels for normal vascular relaxation.
Main Methods:
- Utilized alpha1H T-type Ca2+ channel-deficient mice (alpha(1)3.2-null).
- Performed contractile and relaxation studies on isolated coronary arteries.
- Investigated the effects of T-channel blockade with Ni2+ on wild-type arteries.
Main Results:
- Alpha(1)3.2-null mice displayed constitutively constricted coronary arterioles and myocardial fibrosis.
- Coronary arteries from alpha(1)3.2-null mice showed impaired relaxation to acetylcholine and nitroprusside.
- Acute T-channel blockade with Ni2+ abolished relaxation in wild-type coronary arteries.
Conclusions:
- Calcium influx through alpha1H T-type Ca2+ channels is essential for normal coronary artery relaxation.
- Alpha1H T-type Ca2+ channels play a critical role in maintaining vascular homeostasis and preventing constriction.