[Respiratory effects of PGI-2 in the pig]

In anaesthetised pig the intravenous perfusion of 2 micrograms/Kg/min/4 min of PGI2 induces within 30'' respiratory changes that spontaneously disappear after perfusion. The PGI2 induces a decrease of respiratory frequency while total pulmonary resistance increases significantly. This changes of pattern of breathing are correlated to tonus of vagus nerve and after vagosimpathectomy are not present. The relationship of tidal volume/frequency has been evaluated according to the blood pressure variation.