Abnormal coronary function in mice deficient in alpha1H T-type Ca2+ channels.
Chen CC,
Lamping KG,
Nuno DW,
Barresi R,
Prouty SJ,
Lavoie JL,
Cribbs LL,
England SK,
Sigmund CD,
Weiss RM,
Williamson RA,
Hill JA,
Campbell KP.
Howard Hughes Medical Institute, University of Iowa, Iowa City, IA 52242, USA.
Calcium ion (Ca2+) influx through voltage-gated Ca2+ channels is important for the regulation of vascular tone. Activation of L-type Ca2+ channels initiates muscle contraction; however, the role of T-type Ca2+ channels (T-channels) is not clear. We show that mice deficient in the alpha1H T-type Ca2+ channel (alpha(1)3.2-null) have constitutively constricted coronary arterioles and focal myocardial fibrosis. Coronary arteries isolated from alpha(1)3.2-null arteries showed normal contractile responses, but reduced relaxation in response to acetylcholine and nitroprusside. Furthermore, acute blockade of T-channels with Ni2+ prevented relaxation of wild-type coronary arteries. Thus, Ca2+ influx through alpha1H T-type Ca2+ channels is essential for normal relaxation of coronary arteries.
PMID: 14631046 [PubMed - indexed for MEDLINE]