Blood Pressure Drugs May Act as One

A report in the September 9, 2003, issue of Circulation stated that beta-blockers and angiotensin-converting enzyme (ACE) inhibitors used to treat high blood pressure appear to work together on the molecular level in the body. (Beta-blockers act on receptors that control the amount of blood delivered to the body at times of stress. ACE inhibitors act on receptors that regulate growth of heart muscle.)

?There has been evidence that these 2 receptors act as a pair, holding hands in the cell membrane to form what we call dimers,? said study author Howard A. Rockman, MD, a professor of medicine at Duke University Medical Center. If human studies confirm the finding, it could simplify the treatment of high blood pressure, which now usually requires people to take 2 drugs, according to Dr. Rockman.

To test their theory, the researchers first had to grow mouse heart cells in laboratory cultures. Once the beta-blocker was added to the cultures, the cell had a markedly weaker than expected reaction to a chemical that stimulates angiotensin receptors, showing that the beta-blocker was affecting those receptors. In step 2, mice were given an angiotensin-receptor blocker, followed by a chemical that activates beta-receptors.Those beta-receptors remained inactive, as would happen if they were exposed to a beta-blocker. ?Since both those blockers act on each other?s receptors, we could start a patient with the less difficult of the 2 medications,? Dr. Rockman said.