Rat urotensin-II-induced main pulmonary artery contractions are mediated by MAPK * / 中国病理生理杂志

ABSTRACT

AIM:To investigate rat Urotensin-II(ra t U-II)-induced vasoconstriction of rat main pulmonary arteries and the role of mitogen-activated protein kinase(MAPK). METHODS: The main pulmon ary artery was dissected from the male Sprague -Dawley rats and artery ring width was 3-4 mm. Concentration-response curves wer e gene rated to rat U-II(0 03 nmol/L-30 nmol/L).Inhibitor of MAPK,PD 98059(0 1 ?mol/ L -10 ?mol/L) were added into the medium after rat U-II(30 nmol/L)induced vasoc onstriction had reached plateau to construct the relaxant concentration-respons e curves and their EC 50 and E max . RESULTS: Rat U-II was a potent vasoconstrictor of isolated rat main pulmonary arteries [EC 50 =7 95?0 4 0, E max =(14 28?6 34)% of the response to 60 mmol/L KCl]; PD 98059 caused c oncentration-dependent relaxations of rat U-II precontracted arteries [EC 50 =5 91?0 45, E max =(81 39?13 65)%]. CONCLUSION: Rat U- II was a potent vasoconstrictor of rat main pulmonary arteries and this response was med iated through MAPK.