Hepatitis B Virus (HBV)

Category: Cardiovascular protection

New insights into the role of nitric oxide in cardiovascular protection (part 11). CONCLUSIONS

In summary, cAMP levels regulated by PDE4 and PDE2 may up-regulate the nitric oxide-cGMP pathway in endothelial cells. Conversely, in smooth muscle cells cGMP (related to nitric oxide) may down-regulate PDE3 and therefore potentiate the effect of PDE4 inhibition. Reciprocal interactions between cAMP and cGMP are favoured by nitric oxide in endothelial cells, as in […]

New insights into the role of nitric oxide in cardiovascular protection

New insights into the role of nitric oxide in cardiovascular protection (part 10)

In the presence of PDE3 inhibitor, the EC50 values of PDE4 inhibitors were two- to sixfold their IC50 values on purified vascular PDE4. The presence of functional endothelium decreased EC50 values of PDE4 inhibitors equivalent to their IC50 values on the enzyme . Therefore, PDE3 inhibition and the presence of functional endothelium both enabled the […]

New insights into the role of nitric oxide in cardiovascular protection (part 9)

Because rolipram acts specifically on PDE4, which hydrolyzes only cAMP, this L-arginine-dependent increase in cGMP level suggests that an increase in cAMP level may up-regulate the basal L-arginine-nitric oxide-cGMP pathway in endothelial cells.Vascular smooth muscle: Vascular smooth muscle cells contain PDE3 and PDE4 as major cAMP-hydrolyzing enzymes . Because the cGMP increase related to nitric […]

New insights into the role of nitric oxide in cardiovascular protection

New insights into the role of nitric oxide in cardiovascular protection (part 8)

¬†As shown in Figure 2A, neither the PDE2 inhibitor nor the PDE4 inhibitor alone increased cAMP level, regardless of presence or absence of nitric oxide-cGMP pathway modulators. However, the combination of both inhibitors potently increased cAMP levels (eight- to 13-fold compared with drug vehicle). In the same samples, no significant effects of PDE2 and PDE4 […]

New insights into the role of nitric oxide in cardiovascular protection (part 7)

Reciprocal regulations between nitric oxide and cyclic nucleotides – role of cyclic nucleotide phosphodiesterases: By increasing tissue cGMP levels, nitric oxide may interfere with cyclic nucleotide metabolism and, therefore, participate in the regulation of vascular relaxation. Cyclic nucleotide PDE comprises seven families of isozymes that hydrolyze cyclic nucleotides . Among them, PDE2, PDE3 and PDE4 […]

New insights into the role of nitric oxide in cardiovascular protection

New insights into the role of nitric oxide in cardiovascular protection (part 6)

Recently, in accordance with these observations, the appearance of EPR-detectable myoglobin-nitric oxide was found in S-nitrosoglutathione-pretreated rat hearts, after prolonged ischemia, but not in nonischemic hearts . Both LPS and S-nitrosoglutathione pretreatment are associated with cardioprotection against ischemia-reperfusion injury.Therefore, it might be suggested that stimulated nitric oxide production during a preischemic period may lead to […]

New insights into the role of nitric oxide in cardiovascular protection

New insights into the role of nitric oxide in cardiovascular protection (part 5)

It is known that nitric oxide may form nitrosyl iron heme complexes as well as iron nonheme complexes with thiol ligands both in vitro and in vivo. These can be detected by EPR spectroscopy . Low oxygen tension is favourable for the formation of such complexes . Therefore, one can suggest that increased nitric oxide […]

Tags