TY - JOUR
T1 - Neurally released ATP mediates endothelium-dependent hyperpolarization in the circular smooth muscle cells of chicken anterior mesenteric artery
AU - Draid, Marwan
AU - Shiina, Takahiko
AU - El-Mahmoudy, Abu Bakr
AU - Boudaka, Ammar
AU - Shimizu, Yasutake
AU - Takewaki, Tadashi
PY - 2005/12
Y1 - 2005/12
N2 - 1 The object of the present study was to clarify the neurotransmitter(s) controlling membrane responses to electrical field stimulation (EFS) in the circular smooth muscle cells of first-order branches of chicken anterior mesenteric artery. 2 EFS (five pulses at 20 Hz, 1 ms) evoked a hyperpolarization of amplitude -21.6±1.2 mV, total duration 21.8±1.2 s and latency 641.7±81.9 ms. The response was tetrodotoxin-sensitive and nonadrenergic noncholinergic (NANC) in nature. 3 The NANC response was blocked by the nonspecific purinergic antagonist, suramin, indicating that the response is mediated by the neurotransmitter adenosine 5′-triphosphate (ATP). 4 Either desensitization or blockade of P2Y receptor with its putative agonist 2-methylthioATP (1 μM for 30 min) or with its antagonist cibacron blue F3GA (10 μM), respectively, abolished the purinergic hyperpolarization. PPADS at concentrations up to 100 μM had no effect on the EFS-induced response, indicating that this response is mediated through P2Y, but not P2X, receptor. In addition, the response was completely abolished by two specific P2Y1 receptor antagonists, namely, MRS 2179 (300 nM) and A3P5PS (10 μM). 5 Removal of the endothelium abolished the purinergic hyperpolarization, which was converted, in some preparations, to a small depolarization, indicating that the hyperpolarizing response is endothelium-dependent. 6 The present study suggests that in first-order branches of chicken anterior mesenteric artery, ATP released from perivascular nerves may diffuse to the endothelium-activating P2Y1 receptor to induce release of an inhibitory substance that mediates hyperpolarization in the circular smooth muscle.
AB - 1 The object of the present study was to clarify the neurotransmitter(s) controlling membrane responses to electrical field stimulation (EFS) in the circular smooth muscle cells of first-order branches of chicken anterior mesenteric artery. 2 EFS (five pulses at 20 Hz, 1 ms) evoked a hyperpolarization of amplitude -21.6±1.2 mV, total duration 21.8±1.2 s and latency 641.7±81.9 ms. The response was tetrodotoxin-sensitive and nonadrenergic noncholinergic (NANC) in nature. 3 The NANC response was blocked by the nonspecific purinergic antagonist, suramin, indicating that the response is mediated by the neurotransmitter adenosine 5′-triphosphate (ATP). 4 Either desensitization or blockade of P2Y receptor with its putative agonist 2-methylthioATP (1 μM for 30 min) or with its antagonist cibacron blue F3GA (10 μM), respectively, abolished the purinergic hyperpolarization. PPADS at concentrations up to 100 μM had no effect on the EFS-induced response, indicating that this response is mediated through P2Y, but not P2X, receptor. In addition, the response was completely abolished by two specific P2Y1 receptor antagonists, namely, MRS 2179 (300 nM) and A3P5PS (10 μM). 5 Removal of the endothelium abolished the purinergic hyperpolarization, which was converted, in some preparations, to a small depolarization, indicating that the hyperpolarizing response is endothelium-dependent. 6 The present study suggests that in first-order branches of chicken anterior mesenteric artery, ATP released from perivascular nerves may diffuse to the endothelium-activating P2Y1 receptor to induce release of an inhibitory substance that mediates hyperpolarization in the circular smooth muscle.
KW - ATP
KW - Chicken
KW - Endothelium
KW - Mesenteric artery
KW - NANC
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U2 - 10.1038/sj.bjp.0706413
DO - 10.1038/sj.bjp.0706413
M3 - Article
C2 - 16231006
AN - SCOPUS:28444470493
SN - 0007-1188
VL - 146
SP - 983
EP - 989
JO - British Journal of Pharmacology
JF - British Journal of Pharmacology
IS - 7
ER -