cyclic-gmp and bis(p-chlorophenyl)acetic-acid

Obesity is correlated with chronic low-grade inflammation. Thus the induction of inflammation could be used to stimulate adipose tissue formation in tissue-engineering approaches. As nitric oxide (NO) is a key regulator of inflammation, we investigated the effect of NO and its downstream signaling molecule guanosine 3',5'-cyclic monophosphate (cGMP) as well as adenosine 3',5'-cyclic monophosphate (cAMP) on preadipocytes in vitro.. Preadipocytes were isolated from human subcutaneous adipose tissue, cultured until confluence, and differentiated. The NO donor diethylenetriamine (DETA)/NO (30-150 microm) was added during proliferation and differentiation. Additionally, cGMP/cAMP analogs 8-bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP), 8-(4-chlorophenylthio)-guanosine 3',5'-cyclic monophosphate (8-pCPT-cGMP) and 8-bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP), and the adenylyl cyclase activator forskolin, specific guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) and adenylyl cyclase inhibitor 2'-5'-dideoxyadenosine (ddA), were applied. Proliferation and differentiation were evaluated.. DETA/NO in combination with the standard differentiation procedure significantly enhanced maturation of precursor cells to adipocytes. Proliferation, in contrast, was inhibited in the presence of NO. The application of cGMP and cAMP, respectively, increased pre-adipocyte differentiation to an even higher extent than NO. Inhibitors of the underlying pathways caused a significant decrease in adipogenic conversion.. Our results support the application of NO donors during transplantation of preadipocytes in a 3-dimensional setting to accelerate and optimize differentiation. The results suggest that, instead of the rather instable and reactive molecule NO, the application of cGMP and cAMP would be even more effective because these substances have a stronger adipogenic effect on preadipocytes and a longer half-life than NO. Also, by applying inhibitors of the underlying pathways, the induced inflammatory condition could be regulated to the desired level.

Topics: Adenylyl Cyclase Inhibitors; Adipocytes; Adipogenesis; Adult; Cell Proliferation; Cells, Cultured; Colforsin; Cyclic AMP; Cyclic GMP; DDT; Guanylate Cyclase; Humans; Male; Middle Aged; Nitric Oxide; Oxadiazoles; Quinoxalines; Second Messenger Systems; Stem Cells; Subcutaneous Fat; Tissue Engineering

The effects of bath application of the nitric oxide (NO) precursor L-arginine (L-ARG) on the resting activity (RA) of afferent crista fibers were studied in isolated statocysts of the cuttlefish Sepia officinalis under various experimental conditions. L-ARG (threshold 10(-7) M) had three different effects: inhibition, excitation, and excitation followed by an inhibition; only the inhibitory effect of L-ARG was dose-dependent. D-Arginine (D-ARG) had no effect. When the preparation was pre-treated with NO synthase inhibitors (N(G)-Nitric-L-arginine methyl ester HCl (L-NAME), N(G)-Nitro-L-arginine (L-NOARG)), both the inhibitory and the excitatory effects of L-ARG significantly decreased at higher concentrations (10(-5 to -4) M), or were completely blocked at lower concentrations (10(-7 to -6) M), of L-ARG. When the preparation was pre-treated with guanylate cyclase inhibitors (1H-[1,2, 4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ), methylene blue (M-BLU), cystamine (CYS)), L-ARG had only excitatory effects, whereas its effects were only inhibitory when the preparation was pre-treated with adenylate cyclase inhibitors 2',3'-dideoxyadenosine (DDA), MDL-12330A (MDL), nicotinic acid (NIC-A)). L-ARG had no effects when the pre-treatment was with a guanylate cyclase inhibitor and an adenylate cyclase inhibitor combined; in that situation, the RA of the afferent fibers remained. These data indicate that in cephalopod statocysts, a cGMP and a cAMP signal transduction pathway (presumably via the generation of NO) are responsible for the effects of L-ARG on the RA of crista afferent fibers. They also indicate that the L-ARG-cGMP pathway is the dominant pathway and is inhibitory, and that both pathways have only modulatory effects on, but are not essential for, the generation of the RA.

Topics: Action Potentials; Adenylyl Cyclase Inhibitors; Adenylyl Cyclases; Animals; Arginine; Cyclic AMP; Cyclic GMP; Cystamine; DDT; Decapodiformes; Dose-Response Relationship, Drug; Enzyme Inhibitors; Female; Guanylate Cyclase; Hair Cells, Vestibular; Imines; Immunosuppressive Agents; Male; Methylene Blue; Mollusca; NADP; NG-Nitroarginine Methyl Ester; Niacin; Nitric Oxide; Nitroarginine; Oxadiazoles; Postural Balance; Quinoxalines; Sodium Chloride