Search results for "Cyclic GMP"
showing 10 items of 99 documents
Nitric oxide and excitatory postsynaptic currents in immature rat sympathetic preganglionic neurons in vitro.
1997
Neuronal nitric oxide synthase immunoreactivity was localized to sympathetic preganglionic neurons of the intermediolateral cell column and cyclic GMP immunoreactivity to nerve fibers projecting into the intermediolateral cell column of 20-25-day-old rats. Whole-cell patch-clamp recordings were made from sympathetic preganglionic neurons in spinal cord slices of immature rats and the role of nitric oxide and cyclic GMP on excitatory postsynaptic currents was studied. Superfusing the slices with the nitric oxide precursor L-arginine (300 microM) increased the amplitude of evoked excitatory postsynaptic currents as well as the frequency of spontaneous miniature excitatory postsynaptic current…
Inflammation in the Human Periodontium Induces Downregulation of the α1- and β1-Subunits of the sGC in Cementoclasts
2021
Nitric oxide (NO) binds to soluble guanylyl cyclase (sGC), activates it in a reduced oxidized heme iron state, and generates cyclic Guanosine Monophosphate (cGMP), which results in vasodilatation and inhibition of osteoclast activity. In inflammation, sGC is oxidized and becomes insensitive to NO. NO- and heme-independent activation of sGC requires protein expression of the &alpha
Effects of N2, O2'-dibutyril cyclic GMP on the nucleoside phosphotransferase activity of the retina of the chick embryos.
1977
In the retina of the chick embryo, 2 different forms of nucleoside phosphotransferase take part in the phosphorylation of thymidine. One is an unstable form with higher molecular weight. The other with lower m. wt is a stable form. This paper shows that N2, O2′-dibutyril cyclic GMP causes a marked decrement of the activity of the unstable nucleoside phosphotransferase.
Explaining the phenomenon of nitrate tolerance.
2005
During the last century, nitroglycerin has been the most commonly used antiischemic and antianginal agent. Unfortunately, after continuous application, its therapeutic efficacy rapidly vanishes. Neurohormonal activation of vasoconstrictor signals and intravascular volume expansion constitute early counter-regulatory responses (pseudotolerance), whereas long-term treatment induces intrinsic vascular changes, eg, a loss of nitrovasodilator-responsiveness (vascular tolerance). This is caused by increased vascular superoxide production and a supersensitivity to vasoconstrictors secondary to a tonic activation of protein kinase C. NADPH oxidase(s) and uncoupled endothelial nitric oxide synthase …
Two distinct Ca2+ influx pathways activated by the bradykinin B2 receptor.
1996
The hormone-induced depletion of cellular Ca stores provides a signal for the Ca2+ influx into electrically non-excitable cells; however, the underlying molecular mechanisms remain elusive. Therefore, we analyzed bradykinin-activated Ca2+ influx into human foreskin fibroblast cells, HF-15, by fura-2 and 45Ca labeling to discriminate between Ca2+ influx into the fura-sensitive compartment and Ca uptake into fura-insensitive Ca stores. Bradykinin-activated CaZt influx into the fura-sensitive compartment was blocked by inhibitors of NO synthases. These inhibitors also suppressed bradykinin-activated increases in cGMP, indicating that the NO-dependent increase in cGMP is involved in the activat…
Altered antioxidant-oxidant status in the aqueous humor and peripheral blood of patients with retinitis pigmentosa.
2013
Retinitis Pigmentosa is a common form of hereditary retinal degeneration constituting the largest Mendelian genetic cause of blindness in the developed world. It has been widely suggested that oxidative stress possibly contributes to its pathogenesis. We measured the levels of total antioxidant capacity, free nitrotyrosine, thiobarbituric acid reactive substances (TBARS) formation, extracellular superoxide dismutase (SOD3) activity, protein, metabolites of the nitric oxide/cyclic GMP pathway, heme oxygenase-I and inducible nitric oxide synthase expression in aqueous humor or/and peripheral blood from fifty-six patients with retinitis pigmentosa and sixty subjects without systemic or ocular …
A key role for cyclic nucleotide gated (CNG) channels in cGMP-related retinitis pigmentosa.
2011
The rd1 natural mutant is one of the first and probably the most commonly studied mouse model for retinitis pigmentosa (RP), a severe and frequently blinding human retinal degeneration. In several decades of research, the link between the increase in photoreceptor cGMP levels and the extremely rapid cell death gave rise to a number of hypotheses. Here, we provide clear evidence that the presence of cyclic nucleotide gated (CNG) channels in the outer segment membrane is the key to rod photoreceptor loss. In Cngb1(-/-) x rd1 double mutants devoid of regular CNG channels, cGMP levels are still pathologically high, but rod photoreceptor viability and outer segment morphology are greatly improve…
Phosphodiesterase inhibition induces retinal degeneration, oxidative stress and inflammation in cone-enriched cultures of porcine retina.
2013
nherited retinal degenerations affecting both rod and cone photoreceptors constitute one of the causes 74 of incurable blindness in the developed world. Cyclic guanosine monophosphate (cGMP) is crucial in the 75 phototransduction and, mutations in genes related to its metabolism are responsible for different retinal 76 dystrophies. cGMP-degrading phosphodiesterase 6 (PDE6) mutations cause around 4e5% of the retinitis 77 pigmentosa, a rare form of retinal degeneration. The aim of this study was to evaluate whether phar- 78 macological PDE6 inhibition induced retinal degeneration in cone-enriched cultures of porcine retina 79 similar to that found in murine models. PDE6 inhibition was induced…
Differential expression and interaction with the visual G-protein transducin of centrin isoforms in mammalian photoreceptor cells.
2004
Photoisomerization of rhodopsin activates a heterotrimeric G-protein cascade leading to closure of cGMP-gated channels and hyperpolarization of photoreceptor cells. Massive translocation of the visual G-protein transducin, Gt, between subcellular compartments contributes to long term adaptation of photoreceptor cells. Ca(2+)-triggered assembly of a centrin-transducin complex in the connecting cilium of photoreceptor cells may regulate these transducin translocations. Here we demonstrate expression of all four known, closely related centrin isoforms in the mammalian retina. Interaction assays revealed binding potential of the four centrin isoforms to Gtbetagamma heterodimers. High affinity b…
Functional coupling of nitric oxide synthase and soluble guanylyl cyclase in controlling catecholamine secretion from bovine chromaffin cells
1997
This study was designed to evaluate whether the enzymes of the nitric oxide/cyclic-GMP pathway, nitric oxide synthase and soluble guanylyl cyclase, are functionally coupled in controlling catecholamine secretion in primary cultures of bovine chromaffin cells. In immunocytochemical studies, 80-85% of the tyrosine hydroxylase-positive chromaffin cells also possessed phenylethanolamine-N-methyltransferase, f1p4cating their capability to synthesize epinephrine. Immunoreactivity for neuronal-type nitric oxide synthase was found in over 90% of all chromaffin cells. Reverse transcription-polymerase chain reaction also demonstrated neuronal-type nitric oxide synthase messenger RNA. Immunoreactivity…