Inhibition of activated K-opioid receptor to myocardical hypertrophy induced by ET-1 in neonatal rats by extracellular signal-regulated kinase pathway / 中国药理学通报

ABSTRACT

Aim To investigate the inhibitory effect of kappa-opioid receptor(κ-OR)stimulation on extracellular signal-regulated kinase pathway on ET-1-induced cardiomyocyte hypertrophy in vitro cultured myocardial cells from neonatal rats.Methods Myocardial cells of neonatal rats were cultured in vitro.The hypertrophic myocytes were induced by ET-1(10 nmol·L-1)before κ-OR agonist U50488H(1 μmol·L-1)was administered.The antihypertrophic effect of κ-OR stimulation was observed in the presence of U0126(1μmol·L-1), Ro-31-8220(50 nmol·L-1)and PTX(5 mg·L-1).The cardiomyocytes volume was measured by computer photographalysis system.The relative expression of ERK1/2 was determined by Western blot.The morphological changes in cardiomyocytes were observed under an inverted phase contrast microscope.The expression of mRNA of atrial natriuretic peptide(ANP)was determined by RT-PCR.Results Compared with normal control group, ET-1 could induced cardiomyocyte hypertrophy.Compared with ET-1 model group, U50488H(1 μmol·L-1)could obviously inhibit ET-1-induced increase of the cardiomyocytes volume, expression of ANPmRNA and expression of ERK1/2, which was similar to U0126(1 μmol·L-1)and Ro-31-8220(50 nmol·L-1); however, the inhibitory effects of U50488H were partly lost when preincubated with U0126(1 μmol·L-1)and Ro-31-8220(50 nmol·L-1); the inhibitory effects of U50488H, U0126(1 μmol·L-1)and Ro-31-8220(50 nmol·L-1)were lost when preincubated with NOR-BNI.Conclusion The stimulation of kappa-opiod can inhibit myocardial hypertrophy induced by ET-1, which is possibly via attenuating ERK1/2.