title: Arteriolar and venular reactivity to superfusate pO2 in tissues with different metabolic capacity. A study in skeletal muscle and mesentery of the rat.
abstract: In skeletal muscle (extensor hallucis proprius) and mesentery of anesthetised (pentobarbital 30 mg/kg) female rats (200 g) we have compared reactivity to O2 of arterioles and venules with their response to a vasoconstrictor (epinephrine 5.5 x 10(-7) M) and a vasodilator (adenosine 10(-4) M). Muscle arterioles fully constricted with O2 and epinephrine and dilated with adenosine (22%). Muscle venules did not respond to changes in superfusate pO2, constricted 18% with epinephrine and dilated 10% with adenosine. In the mesentery changes in superfusate pO2 had no effect on diameters of arterioles or venules but epinephrine fully constricted arterioles and constricted venules by 19%, while adenosine dilated arterioles (6%) but not venules. When we set arteriolar and venular diameters during adenosine superfusion at 100%, muscle arterioles appeared to operate at 63% and mesenterial arterioles at 84% of maximal diameter at normal tissue pO2. For venules these percentages were 91 and 97%, respectively. Arterioles and venules in muscle thus have higher tone and muscle arterioles are greatly sensitive to changes in tissue pO2 while in our preparation mesenterial arterioles are not.
authors.affiliation: Laboratory for Physiology, Free University, Amsterdam, The Netherlands.
authors.forename: G C
authors.initials: GC
authors.lastname: Van den Bos
authors.forename: N
authors.initials: N
authors.lastname: Westerhof
authors.forename: N
authors.initials: N
authors.lastname: Hoogerwerf
authors.forename: A H
authors.initials: AH
authors.lastname: Sicking
mesh_terms: D000241:Adenosine / Q000494:pharmacology*; D000818:Animals; D001160:Arterioles / Q000187:drug effects; D004837:Epinephrine / Q000494:pharmacology*; D005260:Female; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000378:metabolism; D008642:Mesenteric Veins / Q000187:drug effects* / Q000378:metabolism; D008833:Microcirculation; D009132:Muscles / Q000098:blood supply* / Q000187:drug effects / Q000378:metabolism; D010100:Oxygen / Q000494:pharmacology*; D010313:Partial Pressure; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains; D014699:Venules / Q000187:drug effects
chemical_list: D000241:Adenosine; D010100:Oxygen; D004837:Epinephrine