During the past decade, great strides have been made in our un derstanding of the biochemistry and pharmacology of the alpha-l adrenergic receptor. The alpha-l adrenergic receptor plays a key role in biological function. This is evidenced by the fact that the alpha-l adrenergic receptor plays a prominent functional role in most organs of the body and in the key systems responsible for survival of the organism and maintenance of optimum biological activity. This is most apparent in the cardiovascular system, in which alpha-l adrenergic receptors are the single most important receptor involved...