EFFECT OF 1-(2,6-DIMETHYLPHENOXY)-2-(3,4-DIMETHOXYPHENYL-ETHYLAMINO) PROPANE HYDROCHLORIDE ON EXPRESSION OF COLLAGEN TYPE I AND TYPE III mRNA IN CULTURED CARDIAC FIBROBLASTS

AIM: The collagen subtypes I(Co I) and III(Co III) are essential components of the cardiac extracellular matrix (ECM) in maintaining the functional integrity of the heart. The aim of the present study was to investigate whether norepinephrine stimulation known to induce cardiac hypertrophy might be involved in the regulation of the Co I and Co III mRNA expression, and effects of 1-(2,6-dimethylphenoxy)-2-(3,4-dimethoxyphenylethylamino) propane hydrochloride (DDPH) on expression of Co I and Co III mRNA. METHODS: Neonatal rat cardiac fibroblasts were prepared from Sprague-Dawley rats(1～3 d after birth). Norepinephrine was used as hyperplastic agent, Co I, Co III and mRNA expression were measured by RT-PCR. RESULTS: Stimulation of neonatal rat cardiac fibroblasts with 1 μmol.L^-1 norepinephrine for 24 h resulted in a significant increase of the Co I mRNA(10 fold) and Co III mRNA(3.1 fold). The changes on the expression level were blocked by the DDPH. CONCLUSION: The data demonstrate that the Co I and Co III mRNA levels were up-regulated by the activation of the adrenergic signal transduction pathway and DDPH was shown to decrease the expression levels of Co I and Co III mRNA.