Figure 3.
Expression of phenylephrine-induced foetal genes in cultured neonatal cardiomyocytes. Cardiomyocytes were stimulated with phenylephrine (PE) (25 μM) for 24 h in the presence or absence of propranolol (Pro) (1 μM), metoprolol (Met) (1 μM), ICI 118551 (ICI) (1 μM) or prazosin (Pz) (2 μM). At the end of treatments, total RNA was isolated and real-time TaqMan quantitative PCR was used to assess the expression of the foetal genes. Summary data for ANP, β-MHC, skACT, α-MHC and SERCA from three separate experiments performed in triplicate are shown. Data are presented as 2−ΔΔCt. Expression of ANP, β-MHC and skACT genes significantly increased in response to PE (2.2-, 3.6- and 3.4-fold, respectively). In propranolol-treated cardiomyocytes, induction of the foetal genes by PE was enhanced (ANP, 7.1-fold; and β-MHC, 5.4-fold). Similar results were obtained with metoprolol, but not with ICI 118551. Veh, vehicle. *P<0.05, vs corresponding control group; ‡P<0.05, vs PE group. ANP, atrial natriuretic peptide; β-MHC, β-myosin heavy chain; skACT, skeletal α-actin; α-MHC, α-myosin heavy chain; SERCA, sarcoplasmic reticulum Ca2+-ATPase.