title: alpha,beta-MeATP augments the UTP contraction of rabbit basilar artery.
abstract: The mechanism underlying the interaction between alpha,beta-methyleneadenosine 5'-triphosphate (alpha,beta-MeATP) and uridine 5'-triphosphate (UTP) was investigated using the basilar artery of a rabbit. UTP induced a concentration-dependent contraction, whereas P2X receptor agonists, such as alpha,beta-MeATP and 2-methylthioadenosine 5'-triphosphate (2-MeSATP), did not induce any contraction up to 100 microM. alpha,beta-MeATP augmented the UTP contraction two-fold, immediately and reversibly. This effect was observed with ectonucleotidase inhibition with 1 mM Ni(2+), the removal of extracellular Ca(2+) or Evans blue. The contractile response to adenosine 5'-O-(3-triphosphate) (ATPgammaS), a selective agonist for P2Y(4), was augmented by pretreatment with alpha,beta-MeATP also. ATPgammaS had no additional effect on the UTP contraction fully activated with alpha,beta-MeATP. UTP (100 microM) did not induce an increase in cytosolic Ca(2+) in a rabbit basilar arterial strip; however, in the presence of 1 mM alpha,beta-MeATP, UTP induced a significant increase in cytosolic Ca(2+). These results suggest that alpha,beta-MeATP facilitates the activation by UTP of the P2Y receptor (P2Y(4)) of the rabbit basilar artery through mechanisms other than nucleotidase inhibition, and that it does not do so via a P2X receptor.
authors.affiliation: Department of Neurosurgery, University of Mississippi Medical Center, Jackson, MS, USA. suitecello2003@yahoo.co.jp
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Miyagi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kimura
authors.forename: Robin C
authors.initials: RC
authors.lastname: Carpenter
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Parent
authors.forename: John
authors.initials: J
authors.lastname: Zhang
mesh_terms: D015720:5'-Nucleotidase / Q000037:antagonists & inhibitors; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000818:Animals; D001488:Basilar Artery / Q000187:drug effects*; D002118:Calcium / Q000502:physiology; D020013:Calcium Signaling / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D011817:Rabbits; D018048:Receptors, Purinergic P2 / Q000187:drug effects; D058473:Receptors, Purinergic P2Y2; D014544:Uridine Triphosphate / Q000494:pharmacology*
chemical_list: D018048:Receptors, Purinergic P2; D058473:Receptors, Purinergic P2Y2; C104749:purinoceptor P2Y4; C022571:adenosine 5'-O-(3-thiotriphosphate); D000255:Adenosine Triphosphate; D015720:5'-Nucleotidase; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; D002118:Calcium; D014544:Uridine Triphosphate