Distribution of functional P2X1-like receptor in isolated rabbit arteries.
OBJECTIVE
To clarify the distribution of functional P2X1-like receptors in rabbit arteries.


METHODS
Isometric contractile responses to noradrenaline (NA) and alpha, beta-methylene ATP (alpha, beta-meATP) were observed in the arteries isolated from rabbit renal (Re), femoral (Fe), saphenous (Sa), mesenteric (Me), splenic (Sp), and ear (Ea).


RESULTS
The maximal responses to NA (E(max.NA)) varied among the arteries in an order of Re>Fe>Sa>Me>Sp>Ea. After standardization by the maximal response to KCl (E(max.KCl)), however, the values of E(max.NA)/E(max.KCl) in the six kinds of arteries were almost the same. EC50 values of NA in arteries were different, and the EC50 value of NA in Me artery was 54 times that of Fe artery (P<0.01). The maximal response to alpha, beta-meATP (E(max.alpha, beta-meATP) ) varied among the arteries in an order of Re>Sa=Fe>Ea>Sp=Me, and the values of E<inf>max.alpha, beta-meATP /E(max.KCl) were still different (Fe<Re<Sa=Ea=Sp=Me). The EC50 values of alpha, beta-meATP in regional arteries were almost the same (0.23-0.77 mmol/L). The vasoconstrictive responses induced by alpha, beta-meATP in the Re,Fe,Sa,Me,Sp, and Ea arteries were subject to tachyphylaxis.


CONCLUSIONS
There are functional P2X1-like receptors in the six kinds of arteries used, and the vasoconstrictive responses regulated via the receptors are Fe<Re<Sa=Ea=Sp=Me, which is consistent with the sympathetic innervation of the arteries.
Ren
Lei-Ming
LM
Department of Pharmacology, School of Pharmacy, Hebei Medical University, Shijiazhuang 050017, China. ren-leiming@263.net
Zhang
Miao
M
D000818:Animals; D001158:Arteries / Q000294:innervation / Q000378:metabolism / Q000502:physiology; D004730:Endothelium, Vascular / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D011817:Rabbits; D018048:Receptors, Purinergic P2 / Q000378:metabolism* / Q000502:physiology; D058469:Receptors, Purinergic P2X; D013564:Sympathetic Nervous System / Q000502:physiology; D014661:Vasoconstriction / Q000502:physiology
D018048:Receptors, Purinergic P2; D058469:Receptors, Purinergic P2X