Lack of effect of morphine and buprenorphine on hypoxic pulmonary vasoconstriction in the isolated perfused cat lung and the perfused lobe of the dog lung.

In an isolated perfused cat lung preparation and a perfused lobe of dog lung preparation a pressor response of the pulmonary circulation was elicited to alveolar hypoxia (5% oxygen). The magnitude of this reponse was not affected by either of the opioid drugs, morphine or buprenorphine.