Endogenous ATP released by electrical field stimulation causes contraction via P2x- and P2y-purinoceptors in the isolated tail artery of rats.
Electrical field stimulation (EFS) caused contraction of isolated tail arteries of rats. The EFS-induced contraction showed frequency-dependence and was entirely abolished by the sodium channel blocker tetrodotoxin (1 x 10(-7) M). The EFS-induced (at 20 Hz) contraction was reduced by about 60% in the presence of phentolamine (1 x 10(-6) M). Therefore, later experiments were carried out in the presence of phentolamine. Pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) (1 x 10(-8)-1 x 10(-6) M) and basilen blue E-3G (3 x 10(-5)-5 x 10(-5) M), P2-receptor antagonists, significantly inhibited the contraction evoked by EFS. In addition, PPADS significantly inhibited the contractions induced by ATP (1 x 10(-4) M) and a selective P2x-receptor agonist, alpha,beta-methylene ATP (1 x 10(-6) M). In contrast, basilen blue E-3G did not inhibit alpha,beta-methylene ATP-induced contraction. The ecto-ATPase activator apyrase (5 and 10 U/ml) significantly reduced the EFS-induced contractions. These findings suggest that endogenous ATP released by EFS causes contractions of rat tail artery via both the P2x-receptors and P2y-receptors.
Fukumitsu
A
A
Department of Pharmacology, Faculty of Pharmaceutical Sciences, School of Medicine, Fukuoka University, Japan.
Takano
Y
Y
Iki
A
A
Honda
K
K
Saito
R
R
Katsuragi
T
T
Kamiya
H
H
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D000818:Animals; D001158:Arteries / Q000187:drug effects; D004558:Electric Stimulation; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D009411:Nerve Endings / Q000378:metabolism; D058919:Purinergic P2 Receptor Antagonists; D011732:Pyridoxal Phosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018048:Receptors, Purinergic P2 / Q000187:drug effects*; D012039:Regional Blood Flow / Q000187:drug effects; D013498:Suramin / Q000494:pharmacology; D013623:Tail / Q000098:blood supply; D014227:Triazines / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects
D058919:Purinergic P2 Receptor Antagonists; D018048:Receptors, Purinergic P2; D014227:Triazines; C077792:pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid; C012842:Cibacron Blue F 3GA; D011732:Pyridoxal Phosphate; D013498:Suramin; D000255:Adenosine Triphosphate; C002630:alpha,beta-methyleneadenosine 5'-triphosphate