endothelin-1 and dibutyryl-cyclic-3--5--cytidine-monophosphate

In thick ascending limbs (THALs), nitric oxide (NO) decreases NaCl reabsorption via cGMP-mediated inhibition of Na-K-2Cl cotransporter (NKCC2). In angiotensin (ANG II)-induced hypertension, endothelin-1 (ET-1)-induced NO production by THALs is impaired. However, whether this alters NO's natriuretic effects and the mechanisms involved are unknown. In other cell types, ANG II augments phosphodiesterase 5 (PDE5)-mediated cGMP degradation. We hypothesized that NO-mediated inhibition of NKCC2 activity and stimulation of cGMP synthesis are blunted via PDE5 in ANG II-induced hypertension. Sprague-Dawley rats were infused with vehicle or ANG II (200 ng·kg

Topics: Angiotensin II; Animals; Cyclic CMP; Cyclic GMP; Cyclic Nucleotide Phosphodiesterases, Type 5; Endothelin-1; Hypertension; Loop of Henle; Male; Nitric Oxide; Nitric Oxide Donors; Phosphodiesterase 5 Inhibitors; Rats; Rats, Sprague-Dawley; Solute Carrier Family 12, Member 1; Vardenafil Dihydrochloride

Although keratinocyte-derived factors are known to promote the proliferation and differentiation of human epidermal melanocytes, it is not fully understood whether fibroblast-derived factors work in a similar way.. The aim of this study is to clarify whether fibroblast-derived factors are involved in regulating the proliferation and differentiation of human melanocytes with or without keratinocytes using serum-free culture system.. Human epidermal melanoblasts and melanocytes were cultured in a serum-free growth medium supplemented with fibroblast-derived factors such as keratinocyte growth factor (KGF) with or without keratinocytes, and the effects of KGF on the proliferation and differentiation of melanocytes were studied.. KGF stimulated the proliferation of melanoblasts in the presence of dibutyryl cAMP (DBcAMP), basic fibroblast growth factor (bFGF), transferrin (Tf), and endothelin-1 (ET-1). Although KGF stimulated the differentiation, melanogenesis, and dendritogenesis in the presence of DBcAMP, Tf, and ET-1 without keratinocytes, KGF required the presence of keratinocytes for the stimulation of melanocyte proliferation.. These results suggest that fibroblast-derived KGF stimulates the proliferation of human melanoblasts in synergy with cAMP, bFGF, Tf, and ET-1, the differentiation of melanocytes in synergy with cAMP, Tf, and ET-1, and the proliferation of melanocytes in synergy with cAMP, Tf, ET-1, and undefined keratinocyte-derived factors.

Topics: Cell Differentiation; Cell Proliferation; Cells, Cultured; Coculture Techniques; Cyclic CMP; Dose-Response Relationship, Drug; Endothelin-1; Fibroblast Growth Factor 2; Fibroblast Growth Factor 7; Humans; Keratinocytes; Melanocytes; Paracrine Communication; Time Factors; Transferrin

Downregulation of the sarcoplasmic reticulum calcium ATPase (SERCA2) is associated with diastolic dysfunction in the failing heart. Elevated plasma endothelin-1 (ET) levels are correlated with congestive heart failure suggesting that ET may play a pathophysiological role. We have investigated the ability of ET to regulate SERCA2 gene expression in isolated adult rat ventricular myocytes. We find that ET enhances net protein synthesis by approximately 40% but significantly downregulates SERCA2 mRNA expression, time dependently, by approximately 30-50%, and the expression of SERCA2 protein by approximately 50%. In myoyctes, ET binds to ET(A) receptor that couples to G(q) and G(i) proteins. Inhibition of G(q)-PLC-induced phosphoinositide (PI) hydrolysis with U73122 (1 muM) or inhibition of G(i) protein with pertussis toxin (PTX) abolishes the ability of ET to downregulate SERCA2 mRNA gene expression. Further investigation suggests that ET coupling to PTX-sensitive G(i) with consequent lowering of cAMP is required for downregulation of SERCA2 mRNA levels. Increasing intracellular cAMP quantity using cAMP-specific PDE inhibitor Ro20-1724 or cAMP analog dibutyryl-cAMP reverses ET-induced downregulation of SERCA2 mRNA levels. The data indicate that, in adult myocytes, ET downregulates SERCA2 mRNA and protein levels, and the effect requires cross-talk between G(q) and PTX-sensitive G(i) pathways.

Topics: 4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone; Animals; Cells, Cultured; Cyclic AMP; Cyclic CMP; Down-Regulation; Endothelin-1; Estrenes; GTP-Binding Protein alpha Subunits, Gi-Go; GTP-Binding Protein alpha Subunits, Gq-G11; Heart Ventricles; Male; Mutation; Myocytes, Cardiac; Pertussis Toxin; Phosphodiesterase Inhibitors; Pyrrolidinones; Rats; Rats, Sprague-Dawley; Receptor, Endothelin A; RNA, Messenger; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Signal Transduction; Time Factors; Transfection; Type C Phospholipases