Effects of PGI2 on pattern of breathing in the pig during aortic obstruction.
We studied the effects of prostacyclin on pattern in six anaesthetized pigs with aortic obstruction. PGI2 causes a rightward displacement of VT/TI relationship (Hering-Breuer threshold curve) without a corresponding change in inspiratory flow. With airways occluded at the end respiratory level, we analyze how PGI2 affects the central respiratory rhythm in the absence of the phasic lung volume-related vagal loop. Infusion of prostacyclin causes leftward displacement of the TE/TI relationship and an increase in TTOTo correlated with the hypotensive action. The change in the bulbo-pontine pacemaker is caused by a marked increase in TEo and this suggests that PGI2 can modulate the central respiratory rhythm, independently of the blood pressure level.
D000818:Animals; D001011:Aorta / Q000502:physiology*; D001794:Blood Pressure; D003250:Constriction; D011464:Epoprostenol / Q000494:pharmacology*; D005260:Female; D008297:Male; D011453:Prostaglandins / Q000494:pharmacology*; D012119:Respiration / Q000187:drug effects*; D013552:Swine; D013562:Sympathectomy; D014628:Vagotomy
D011453:Prostaglandins; D011464:Epoprostenol