 |
 |
'Truly revolutionary' insight into how heart drugs work WASHINGTON (February 12, 1998 5:30 p.m. EST http://www.nando.net) - A simple chemical swap could explain why some heart drugs work, and could help scientists design better drugs, researchers said Thursday. Dr. Jonathan Lederer and colleagues at the University of Maryland said they had found a way to make cells let in calcium where they should be letting in sodium, thus changing a delicate but highly important chemical balance. Their findings offer insight into how the heart contracts. Heart contraction fails to work properly in heart failure, which affects 500,000 Americans every year. The contraction of heart muscle cells depends on the cell letting in calcium from the outside. This is done through molecules known as calcium channels -- which give their name to a class of heart drugs known as calcium channel blockers. But sometimes calcium can come in using sodium channels which, as the name implies, are supposed to let sodium into the cell. Writing in the journal Science, Lederer's group said hormones such as adrenaline and drugs based on digitalis can turn sodium channels into calcium channels. "We found that the sodium channel can be stimulated to do something new and different by a neurotransmitter like adrenaline. It can be induced to conduct calcium," Lederer said. "What's more, when the sodium channel conducts calcium in heart muscle, it significantly increases contraction. This is not academic minutia -- this is truly revolutionary." Copyright 1998 Nando.net Copyright 1998 Reuters News Service janet paterson 50-9 / sinemet-selegiline-prozac almonte-ontario-canada / [log in to unmask]