Background: Phosphodiesterase 3A (PDE3A) and phosphodiesterase 3B (PDE3B) play a critical role in the regulation of intracellular level of adenosine 3´,5´-cyclic monophosphate (cyclic AMP, cAMP) and guanosine 3´,5´-cyclic monophosphate (cyclic GMP, cGMP). Subsequently PDE3 inhibitors have shown to relax vascular and inhibit platelet aggregation in cardiovascular disease. Objectives: In th...

8-Nitro-cGMP is an endogenous nucleotide discovered under inflammation conditions as an important mediator of nitric oxide (NO) signaling. Besides cGMP-like behaviour, 8-nitro-cGMP exerts unique cytoprotective effects against oxidative stress. Although the formation of 8-nitro-cGMP from 8-nitro-GTP has previously been proposed, the mechanism by which excess or unused 8-nitro-cGMP is removed fro...

The aim of the study was to assess distribution connexin43 (Cx43) and connexin40 (Cx40) in human bovine ciliary bodies. effect second messengers cAMP cyclic cGMP on Cx43 protein expression also investigated. Enucleated eyes (remnant after corneal transplantation) were used. Tissue preparations anterior segments have proceeded for immunohistochemical staining with polyclonal antibodies Cx40. Iso...

OBJECTIVE In the vascular system, cyclic GMP (cGMP) in smooth muscle cells plays an important role for blood vessel relaxation. Intracellular concentrations of cGMP are thought to be determined by the action of cGMP-generating guanylyl cyclases (sensitive to nitric oxide or natriuretic peptides) and cGMP-degrading phosphodiesterases (PDE1, PDE3, and PDE5). Because functionally relevant cGMP ele...

Phosphodiesterase-5 (PDE5) and cGMP-dependent protein kinase (PKG) play key roles in cGMP signaling. PDE5 has a catalytic domain (C domain) that hydrolyzes cGMP and a regulatory domain (R domain) that binds cGMP at allosteric sites. We recently demonstrated that in corpus cavernosum, PDE5 concentration exceeds basal cGMP by ~5-fold making it possible that its allosteric sites could bind a signi...

The physiological effects of cGMP are largely determined by the activities of intracellular receptors, including cGMP-dependent protein kinase (PKG) and cGMP-binding cyclic nucleotide phosphodiesterases (PDEs), and the distribution of cGMP among these receptors dictates activity of the signalling pathway. In the present study, the effects of PKG-Ialpha or PKG-Ibeta on the rate of cGMP hydrolysi...

The GAFa domain of the cGMP-binding, cGMP-specific phosphodiesterase (PDE5A) was modeled on the crystal structure of PDE2A GAF domain and residues involved in cGMP binding identified. Tandem GAFa and GAFb domains of PDE5A, expressed in Escherichia coli, bound cGMP (K(d) 27 nM). Mutation of aspartate-299 in GAFa, suggested earlier to be critical for cGMP binding, did not abrogate cGMP binding, b...

Cyclic GMP is produced in response to nitric oxide and natriuretic peptides; cGMP is a key regulator of cell proliferation, differentiation, and apoptosis, and plays an important role in many (patho)physiological processes such as synaptic plasticity, angiogenesis, inflammation, and cardiac hypertrophy. The regulation of gene expression by cGMP has been recognized relatively recently, but cGMP-...