enkephalin--leucine-2-alanine and adenosine-3--5--cyclic-phosphorothioate

1. The aims of the present study were to determine whether delta-opioid receptor stimulation enhanced proliferation of and to investigate the role of the extracellular signal-regulated kinase (ERK) pathway in ventricular myocytes from neonatal rats. 2. At concentratins ranging from 10 nmol/L to 10 micromol/L, [D-Ala2,D-Leu5]enkephalin (DADLE) concentration-dependently promoted myocardial growth and DNA synthesis and altered the cytoskeleton. 3. At 1 micromol/L, DADLE also increased the expression and phosphorylation of ERK. 4. These effects of 1 micromol/L DADLE were abolished by 10 micromol/L naltrindole, a selective delta-opioid receptor antagonist, 10 nmol/L U0126, a selective ERK antagonist, 1 micromol/L staurosporine, an inhibitor of protein kinase (PK) C, and 100 micromol/L Rp-adenosine 3',5'-cyclic monophosphorothioate triethylammonium salt hydrate (Rp-cAMPS), an inhibitor of PKA. 5. In conclusion, delta-opioid receptor stimulation enhances the proliferation and development of the ventricular myocytes of neonatal rats. The ERK pathway and related signalling mechanisms, namely PKC and PKA, are involved.

Topics: Analgesics, Opioid; Animals; Animals, Newborn; Butadienes; Cell Proliferation; Cells, Cultured; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cytoskeleton; Dose-Response Relationship, Drug; Enkephalin, Leucine-2-Alanine; Extracellular Signal-Regulated MAP Kinases; Heart Ventricles; Myocytes, Cardiac; Naltrexone; Narcotic Antagonists; Nitriles; Phosphorylation; Protein Kinase C; Protein Kinase Inhibitors; Rats; Rats, Sprague-Dawley; Receptors, Opioid, delta; Signal Transduction; Staurosporine; Thionucleotides; Time Factors