RESUMO
AIM:To investigate the possible mechanism of coronary artery contraction induced by 5-hydroxytryptamine(5-HT).METHODS:Isolated coronary artery rings were obtained from male Wistar rats,and the vas-cular tension meter was used to determine the tension of the coronary artery rings.The effects of inhibitors of different sig-naling pathway on vascular contraction tension induced by 5-HT were observed.RESULTS:Firstly,we found that 5-HT2A receptor antagonist sarpogrelate(1 μmol/L)completely eliminated the coronary artery contraction induced by 5-HT.Phos-pholipase Cβ(PLCβ)inhibitor U73122(10 μmol/L and 50 μmol/L), Rho-related protein kinase inhibitor Y-27632(3 μmol/L and 10 μmol/L)and protein kinase C δ subunit(PKCδ)inhibitor rottlerin(3 μmol/L and 10 μmol/L)signifi-cantly inhibited the contraction of coronary artery ring caused by 5-HT(P<0.05).In addition, compared with the un-treated group,vascular contraction tension induced by 5-HT was also decreased significantly by L-type calcium channel (Cav1.2)blocker nifedipine(1 μmol/L), store-operated Ca2+entry(SOCE)inhibitor SKF96365(10 μmol/L and 30 μmol/L)and 2-aminoethoxydiphenyl borate(2-APB,50 μmol/L and 100 μmol/L)(P<0.05).At the same time,5-HT also induced vasoconstriction after treated with nifedipine(1 μmol/L)Kerbs-Henseleit(K-H)liquid without calcium (P<0.05).CONCLUSION:5-HT activates 5-HT2Areceptor induced coronary artery contraction,possibly related to the PKC/Rho kinase signaling pathway and calcium regulation.