Reflex Coronary Vasoconstriction Caused by Gallbladder Distension in Anesthetized Pigs

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Abstract
Background Gallbladder distension in anesthetized pigs reflexly increases heart rate and arterial pressure by means of afferent vagal pathways and efferent sympathetic mechanisms. The effect of such distension on the coronary circulation is unknown. The present study was undertaken to determine whether gallbladder distension primarily causes reflex changes in left circumflex blood flow. Methods and Results In 21 pigs anesthetized with sodium pentobarbitone (16) or α-chloralose (5), left circumflex blood flow was measured with an electromagnetic flowmeter. A balloon positioned within the gallbladder was distended with volumes of Ringer's solution equal to the volumes of bile previously withdrawn (mean vol: 62 mL; mean gallbladder pressure: 12 mm Hg). Heart rate and arterial pressure were kept constant by atrial pacing and by a pressurized reservoir connected to the left femoral artery. Gallbladder distension always caused a decrease in circumflex blood flow. In 6 of the 16 sodium pentobarbitone–anesthetize...