title: Escherichia coli endotoxemia alters coronary and pulmonary arteriolar responses to platelet products.
abstract: In order to examine the effects of Escherichia coli endotoxemia on coronary and pulmonary microvascular responses to serotonin (5-HT) and ADP, arterioles (80-190 micros diameter) were isolated from pigs 3 h after administration of E. coli endotoxin (150 micrograms/kg, intravenously over 1 h, n = 8) or Ringer's lactate (control, n = 8). Arterioles were studied in vitro in a pressurized, partially contracted, no-flow state with video-microscopy. Precontracted (30-50% of baseline diameter) control coronary arterioles dilated in responses to either 5-HT (24 +/- 2%) or ADP (89 +/- 2%). These relaxations were partially inhibited by indomethacin, but were markedly reduced with nitric oxide synthase inhibition. After 3 h of endotoxemia, 5-HT caused contraction of coronary arterioles which was inhibited with indomethacin. In the presence of indomethacin, coronary vessels from endotoxic pigs relaxed slightly, but significantly, more to 5-HT than did control vessels exposed to indomethacin. In contrast, the relaxation response to ADP was unchanged following endotoxemia. Precontracted (15-30% of baseline diameter) pulmonary arterioles dilated in response to 5-HT (13 +/- 1%) or ADP (67 +/- 3%). Following 3 h of endotoxemia, the pulmonary arteriolar relaxation induced by 5-HT was reduced, whereas the response to ADP was not altered. In both coronary and pulmonary arterioles, relaxation induced by the endothelium-independent vasodilator, sodium nitroprusside, was unaffected by endotoxemia. Thus, coronary and pulmonary microvascular relaxation response to ADP are minimally affected by 3 h of endotoxemia, but relaxation responses to 5-HT are significantly reduced or converted to contractile responses.
authors.affiliation: Department of Surgery, Beth Israel Hospital, Boston, Massachusetts 02215, USA.
authors.forename: F W
authors.initials: FW
authors.lastname: Sellke
authors.forename: S Y
authors.initials: SY
authors.lastname: Wang
authors.forename: T J
authors.initials: TJ
authors.lastname: VanderMeer
authors.forename: M P
authors.initials: MP
authors.lastname: Fink
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology / Q000502:physiology; D000818:Animals; D001160:Arterioles / Q000187:drug effects / Q000503:physiopathology; D001792:Blood Platelets / Q000502:physiology*; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology*; D004731:Endotoxins / Q000633:toxicity*; D004926:Escherichia coli; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000503:physiopathology; D011652:Pulmonary Circulation / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000494:pharmacology / Q000502:physiology; D013552:Swine; D014115:Toxemia / Q000097:blood / Q000209:etiology / Q000503:physiopathology*; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology
chemical_list: D004731:Endotoxins; D012701:Serotonin; D000244:Adenosine Diphosphate; C044101:endotoxin, Escherichia coli