title: Effects of atrial natriuretic peptide on transmural blood flow and reactive hyperemia in the presence of flow-limiting coronary stenosis in the awake dog: evidence for dilation of the intramural vasculature.
abstract: The effects of atrial natriuretic peptide (ANP) on transmural myocardial blood flow distribution and the reactive hyperemic response in the presence and absence of flow-limiting coronary stenosis were examined in chronically instrumented conscious dogs. Ten-second coronary occlusion without subsequent flow restriction resulted in marked reactive hyperemic responses (Doppler flow probes), mean flow debt repayment was 481 +/- 55%. When the 10-second coronary occlusions were followed by a 20-second partial restriction that allowed normal preocclusion coronary inflow, the subsequent reactive hyperemia was significantly augmented, mean flow debt repayment was 938 +/- 91% (p less than 0.05). Pretreatment with ANP (3 micrograms/kg) did not alter the flow debt repayment after a 10-second occlusion without restriction (474 +/- 30%, NS) but attenuated the augmentation of reactive hyperemia resulting from the 20-second inflow restriction, flow debt repayment (613 +/- 66%, NS). Regional myocardial blood flow to the ischemic region was measured during restricted inflow after a 10-second coronary occlusion before and after ANP pretreatment. Before ANP, subendocardial flow decreased (0.54 +/- 0.04 ml/min/g) and subepicardial flow significantly increased (1.03 +/- 0.12 ml/min/g) when compared with the nonischemic zone (subendocardial, 1.03 +/- 0.09 ml/min/g; subepicardial, 0.87 +/- 0.09 ml/min/g, p less than 0.05), indicating maldistribution of the restricted inflow. The resultant subendocardial-to-subepicardial ratio in the ischemic region was significantly decreased when compared with the nonischemic region (0.56 +/- 0.03 vs. 1.18 +/- 0.04, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Medicine, Duke University, Durham, North Carolina.
authors.forename: A
authors.initials: A
authors.lastname: Chu
authors.forename: A
authors.initials: A
authors.lastname: Stakely
authors.forename: C C
authors.initials: CC
authors.lastname: Lin
authors.forename: F R
authors.initials: FR
authors.lastname: Cobb
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology / Q000627:therapeutic use*; D003326:Coronary Circulation / Q000187:drug effects*; D003327:Coronary Disease / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D004285:Dogs; D004353:Drug Evaluation, Preclinical; D006940:Hyperemia / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D008863:Microspheres; D013997:Time Factors; D014664:Vasodilation / Q000187:drug effects*; D014851:Wakefulness / Q000187:drug effects*
chemical_list: D009320:Atrial Natriuretic Factor