Adenosine. Renewed interest in an old drug.

In 1929, A.N. Drury and A. Szent-Gyorgyi wrote,' "As adenylic acid has been found to be a constituent of many and different types of animal cells, an investigation into its general physiological properties in addition to its detailed action upon the mammalian heart seems to us very desirable." The authors then noted that adenosine and adenylic acid "slow the rate of beating, impair conduction from auricle to ventricle.. .," and "lower general arterial pressure and ... dilate the coronary vessels. . . ." An additional important role for adenosine as the mediator of metabolically regulated coronary flow was proposed by Berne2 in 1963, although more