ABSTRACT
AIM: To study the effects of κ-opioid receptor activation on the cardiac hypertrophy, cultured cardiomyocytes were to used study the inhibitory effects of U58,488H on cellular volume and norepinephrine(NE)-induced hypertrophy in the presence or absence of norbinaltorphimine(nor-BNI). METHODS: The protein content was assayed with Lowry's method. The cardiomyocytes' volumes was measured by an eyepiece graticule of inverted microscope. The contracting frequency of cultured myocytes was counted by the inverted microscope. RESULTS: A κ-opioid receptor agonist U50, 488H at (0.1 ∼ 10 μmol·L-1) inhibited the protein content of cultured myocardial cells in normal serum medium in a dose-dependent manner. The inhibitory effects of U50,488H were completely blocked by pretreatment with nor-BNI, a specific κ-opioid receptor antagonist at 1 μmol·L-1. U50,488H (0.1 ∼ 10 μmol·L-1) also inhibited NE-induced cellular hypertrophy in low serum medium, which also were abolished by nor-BNI (1 μmol· L-1). CONCLUSIONS: U50,488H inhibited NE-induced hypertrophy. The inhibitory effects of U50,488H are involved in mediating the action of NE-induced cardiac hypertrophy.
ABSTRACT
AIM To study the effects of ?-opioid receptor activation on the cardiac hypertrophy, cultured cardiomyocytes were to used study the inhibitory effects of U58,488H on cellular volume and norepinephrine(NE)-induced hypertrophy in the presence or absence of norbinaltorphimine(nor-BNI). METHODS The protein content was assayed with Lowry's method. The cardiomyocytes'volumes was measured by an eyepiece graticule of inverted microscope. The contracting frequency of cultured myocytes was counted by the inverted microscope. RESULTS A ?-opioid receptor agonist U50,488H at (0.1～10 ?mol?L -1 ) inhibited the protein content of cultured myocardial cells in normal serum medium in a dose-dependent manner. The inhibitory effects of U50,488H were completely blocked by pretreatment with nor-BNI, a specific ?-opioid receptor antagonist at 1 ?mol?L -1 . U50,488H (0.1～10 ?mol?L -1 ) also inhibited NE-induced cellular hypertrophy in low serum medium, which also were abolished by nor-BNI(1 ?mol?L -1 ). CONCLUSIONS U50,488H inhibited NE-induced hypertrophy. The inhibitory effects of U50,488H are involved in mediating the action of NE-induced cardiac hypertrophy.