Agonist-induced vasoactive responses in isolated perfused porcine dental pulpal arterioles.
A novel isolated perfused pulpal arteriole preparation and microperfusion system was used to evaluate the direct vasoactive responses of pulpal arterioles to selected agonists. Short lengths of porcine pulpal arterioles (101.7+/-2.2 microm o.d., n=105) were dissected out and placed in an environment-controlled bath on the stage of an inverted microscope. Both ends of the vessel were cannulated and perfused at a controlled rate through the lumen. The diameter of the vessel was measured online. Following equilibration, the vessel was challenged with various agonists: adrenaline (epinephrine), noradrenaline (norepinephrine), phenylephrine, dopamine, isoproterenol, 5-hydroxytryptamine, histamine and adenosine. The endothelium-dependent vasodilator acetylcholine was used to evaluate endothelial cell function. Adrenaline, noradrenaline, phenylephrine, 5-hydroxytryptamine and dopamine caused dose-dependent contractions (adrenaline=noradrenaline>phenylephrine>dopamine>5-hydroxytryptamine). Isoproterenol and histamine provoked a dose-dependent dilation. Adenosine produced pronounced vasodilatation in vessels precontracted with 10(-8)M endothelin-1. Functional adrenergic, histamine, 5-hydroxytryptamine and adenosine receptors are, therefore, present in porcine pulpal arterioles. The isolated perfused pulpal arteriole preparation may prove valuable in understanding local control mechanisms of pulpal microcirculation.
Yu
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School of Dentistry, The University of Western Australia, 179 Wellington Street, WA 6000, Perth, Australia. chrisyu@cyllene.uwa.edu.au
Boyd
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Cringle
S J
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Su
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Alder
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Yu
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D000241:Adenosine / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D001160:Arterioles / Q000187:drug effects*; D002395:Catecholamines / Q000494:pharmacology; D003782:Dental Pulp / Q000098:blood supply*; D006632:Histamine / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology; D010477:Perfusion / Q000379:methods; D012039:Regional Blood Flow / Q000187:drug effects; D012701:Serotonin / Q000494:pharmacology; D018709:Statistics, Nonparametric; D013552:Swine; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000494:pharmacology*
D002395:Catecholamines; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D012701:Serotonin; D006632:Histamine; D000241:Adenosine; D007545:Isoproterenol