Drug action on pulmonary circulation of unanesthetized dogs

¹ Department of Pediatrics, Albert Einstein College of Medicine, New York City

A preparation is described which overcomes most of the difficulties previously encountered in the assessment of vasomotor responses of the pulmonary vessels to pharmacologic agents. The use of electromagnetic flow transducers on the main and left pulmonary arteries allows for the observation of immediate local effects following unilateral drug administration before general systemic effects occur. The opposite lung serves as a control, since it is subjected to the same changes of left artrial pressure, pulmonary arterial pressure, and pulmonary blood flow as the test lung. Our studies have demonstrated a direct pulmonary vasoconstrictor response to 5-hydroxytryptamine and acetylcholine in both the conscious and anesthetized dog. Epinephrine was also shown to have a direct pulmonary vasoconstrictor activity, but this could be elicited in only three of the eight dogs studied. Isoproterenol, methoxamine, aminophylline, phenylephrine, -amino butyric acid and pentobarbital had no apparent direct pulmonary vasomotor effect.

Key Words: pulmonary blood flow • pulmonary vasomotor activity • pharmacology of the pulmonary circulation

Submitted on October 9, 1963