Abstract
The pulmonary circulatory changes caused by adrenergic drugs using several techniques have been demonstrated by many investigators. The pulmonary arterial pressure and the pulmonary resistance increase with epinephrine, levarterenol and phenylephrine (1-4). Isoproterenol reduces the pulmonary arterial pressure (5, 6). Methoxamine causes either no change in pulmonary arterial pressure (7) or a significant pulmonary hypotension (4, 8).
On the other hand, the idea of an adrenergic receptive mechanism was introduced by Langley (9, 10) and the receptor concept was reported by Dale (11) describing two kinds of receptors in the general circulation: receptors having an action resulting in excitation and receptors having an action resulting inhibition of the effector cells. But these two kinds of receptors do not exist in all the places of the body both together, sometimes, only one kind of receptor can be found in some places. We have classified the adrenergic receptors in several organs of the body using several adrenergic drugs and the adrenergic blocking agents (12-16).
We have attempted to demonstrate in this paper the kind of adrenergic receptor existing in the pulmonary circulation since no references exist on this problem, even though many investigators have observed the action of adrenergic drugs in the pulmonary circulation, using a limited lung circulation technique and maintaining as normal a circulation as possible.
