cGMP Signaling in Arterioles Revealed by FRET-Based Real-Time Measurement in Mice In Vivo
Abstract
cGMP evokes arteriolar vasorelaxation and is generated in smooth muscle by the soluble guanylyl cyclase (sGC) stimulated by endothelial NO. Phosphodiesterases (PDEs) degrade cGMP and may contribute in diameter regulation. We examined arteriolar cGMP levels in real-time in vivo upon NO and acetylcholine (ACh) and effects of PDE inhibition. Changes in cGMP were measured by FRET using the indicator protein cGi500. Arterioles in the cremaster muscle of anesthetized mice expressing cGi500 were exposed for imaging. They were stimulated with various NO donors (DEA/NO, SNP, SNAP) and ACh with or without PDE inhibition (non-specific: IBMX; PDE-5 specific: sildenafil). Furthermore, dilations induced by ACh and SNP were studied in sGC-deficient mice. DEA/NO and SNAP led to a fast, concentration-dependent rise of fluorescence ratio of cGi500 (by 4.0% at 10 μmol/L), that declined on removal slowly. These ratio changes indicated cGMP increases as verified by inhibition of the sGC using ODQ. PDE inhibition increased cGMP levels slowly despite NO synthase inhibition. However, it did not amplify NO-induced ratio increases, but the decline after drug removal was decelerated. Interestingly, ACh did not modify cGMP levels and dilations were not impaired in sGC-deficient mice. FRET-based imaging allows reliable real-time assessment of arteriolar cGMP levels in vivo. PDE activity does not limit the amplitude, but the duration of cGMP signaling after stimulation. Furthermore, we conclude that ACh…
Read the paper
Related studies
- Drug repositioning: a brief overview
- Cyclic nucleotide phosphodiesterases in Drosophila melanogaster
- Time-resolved in silico modeling of fine-tuned cAMP signaling in platelets: feedback loops, titrated phosphorylations and pharmacological modulation
- Current View on Green Tea Catechins Formulations, Their Interactions with Selected Drugs, and Prospective Applications for Various Health Conditions
- In silico Structure-based Identification of Novel Acetylcholinesterase Inhibitors Against Alzheimer’s Disease
- Development and In Vitro Evaluation of Controlled Release Viagra® Containing Poloxamer-188 Using Gastroplus™ PBPK Modeling Software for In Vivo Predictions and Pharmacokinetic Assessments
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.