The alpha-1D Is the predominant alpha-1-adrenergic receptor subtype in human epicardial coronary arteries.

Objectives: The goal was to identify alpha-1-adrenergic receptor (AR) subtypes in human coronary arteries.

Background: The alpha1-ARs regulate human coronary blood flow. The alpha1-ARs exist as 3 molecular subtypes, alpha1A, alpha1B, and alpha1D, and the alpha1D subtype mediates coronary vasoconstriction in the mouse.