How cocaine elevates blood pressure.

• Position: Cardiovascular System - Medical research

Researchers at The University of Texas Southwestern Medical Center at Dallas have identified the underlying mechanism by which cocaine triggers hypertensive crisis, the most-severe form of high blood pressure and one of the most-common cocaine-related, cardiovascular emergencies in the U.S. The findings may lead to the development of new treatment strategies for cocaine-induced blood pressure elevation and related complications, including stroke and acute myocardial infarction.

"The underlying mechanism of the blood-pressure-raising effect of cocaine use in humans has not been well studied," notes Wanpen Vongpatanasin, senior author of the study and assistant professor of internal medicine. "Most of us believe that cocaine increases blood pressure mainly by preventing clearance or reuptake of noradrenaline from blood vessels into the nerve endings, and the excess levels of noradrenaline cause blood vessels to constrict. However, we found that this mechanism plays a very small role in humans. Instead, cocaine increases blood pressure by stimulation of the heart to cause rapid heartbeat and increased cardiac output. This elevation in blood pressure, if severe or persistent, can lead to damage of multiple vital organs such as the heart, brain, and kidney."

Approximately 25,000,000 Americans have tried cocaine, and the drug is the most-frequent cause of narcotics-related deaths reported by medical examiners. Cocain is the most-commonly used illicit substance among people seeking care in hospital emergency departments or drug treatment centers.

"The textbook explanation of cocaine-related elevated blood pressure is based on evidence from previous studies in rats and mice," explains Meryem Tuncel, lead author of the study and a postdoctoral fellow in hypertension. "However, anesthesia used to sedate these animals interferes with the effects of cocaine on the...