Real-time quantification of subcellular H2O2 and glutathione redox potential in living cardiovascular tissues

Detecting and measuring the dynamic redox events that occur in vivo is a prerequisite for understanding the impact of oxidants and redox events in normal and pathological conditions. These aspects are particularly relevant in cardiovascular tissues wherein alterations of the redox balance are associated with stroke, aging, and pharmacological intervention. An ambiguous aspect of redox biology is how redox events occur in subcellular organelles including mitochondria, and nuclei. Genetically-encoded Rogfp2 fluorescent probes have become powerful tools for real-time detection of redox events. These probes detect hydrogen peroxide (H₂O₂) levels and glutathione redox potential (E_GSH), both with high spatiotemporal resolution. By generating novel transgenic (Tg) zebrafish lines that express compartment-specific Rogfp2-Orp1 and Grx1-Rogfp2 sensors we analyzed cytosolic, mitochondrial, and the nuclear redox state of endothelial cells and cardiomyocytes of living zebrafish embryos. We provide evidence for the usefulness of these Tg lines for pharmacological compounds screening by addressing the blocking of pentose phosphate pathways (PPP) and glutathione synthesis, thus altering subcellular redox state in vivo. Rogfp2-based transgenic zebrafish lines represent valuable tools to characterize the impact of redox changes in living tissues and offer new opportunities for studying metabolic driven antioxidant response in biomedical research.

Effects of salmon calcitonin on plasma renin activity and systolic blood pressure in the rat

Salmon calcitonin, centrally injected, increased plasma renin activity and blood pressure in rats. It is possible that the peptide through an action on the central serotonergic tone stimulated plasma renin activity with subsequent enhancement of blood pressure. Conversely, peripheral administration of the peptide increased plasma renin activity but did not cause changes in blood pressure. Probably, the enhancement of renin may be a physiological response to the renal activity of calcitonin; however, this activity does not seem to involve urinary prostaglandins.

Effects of dopaminergic drugs on cerebellar prostaglandin concentrations

Previous data indicate that the injection of dopaminergic drugs induces changes in cerebellar 3',5'-guanosine monophosphate (cGMP) content. Accordingly, we have investigated the effects of haloperidol, sulpiride, or apomorphine on cerebellar prostaglandin (PG) concentration, a parameter related to cGMP content. Results obtained show that dopamine receptor blocking agents, such as haloperidol and sulpiride, significantly decrease cerebellar PGE2 and PGF2 alpha concentrations, while opposite changes are induced by apomorphine, a dopamine receptor agonist.