The studies showed that mice engineered to lack these calcium channels had constricted coronary arteries and had fibrous tissue in their hearts, which was evident when the animals' hearts reacted to chronic blood restriction. The researchers hypothesize that drugs targeting this calcium channel might one day be used to treat cardiovascular disease by opening arteries.

The researchers, led by Howard Hughes Medical Institute investigator Kevin Campbell, published their findings in the November 21, 2003, issue of the journal Science. Campbell and his colleagues at the University of Iowa collaborated with researchers from the Veterans Administration Medical Center in Iowa City, Loyola University Medical Center and the University of Texas Southwestern Medical Center.

The calcium channel under study is triggered by voltage differences across the cell membrane that cause it to open and allow calcium to flow into the cell. The operation of calcium channels is crucial to a wide array of physiological functions, including transmission of nerve impulses, muscle contraction and activation of genes. Although one type of calcium channel, called the L-type, had been shown to control muscle contraction, the action of the other type, called the T-type, remained largely unknown, said Campbell. The L-channel opens in response to large voltage differences across the cell membrane, while the T-channel responds to a weaker "depolarization," he said.

Campbell and his colleagues first became interested in exploring the T-channel because research by other scientists hinted that it might be involved in the fusion of muscle cells, or myoblasts, to one another during th
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Contact: Jim Keeley
keeleyj@hhmi.org
301-215-8858
Howard Hughes Medical Institute
20-Nov-2003