Journal Article Ppublish 4 citations
PubMed: 39907786 DOI: 10.1007/s00210-025-03854-0
Inhibition of protein phosphatases attenuates A 1-adenosine receptor-stimulation induced negative inotropic effects of cAMP-increasing agents in the isolated human atrium.
Naunyn Schmiedebergs Arch Pharmacol 398(7):9125-9138
Authors: Rebecca Schwarz, Britt Hofmann, Ulrich Gergs, Joachim Neumann
Affiliations
- Institute for Pharmacology and Toxicology, Medical Faculty, Martin-Luther-University Halle-Wittenberg, Magdeburger Str. 4, 06097, Halle (Saale), Germany.
- Cardiac Surgery, Medical Faculty, Martin-Luther-University Halle-Wittenberg, Ernst Grube Str. 40, 06097, Halle (Saale), Germany.
- Institute for Pharmacology and Toxicology, Medical Faculty, Martin-Luther-University Halle-Wittenberg, Magdeburger Str. 4, 06097, Halle (Saale), Germany.
Abstract
N 6-(R)-Phenylisopropyladenosine (R-PIA), an agonist at A 1-adenosine receptors, alone exerts negative inotropic effects (NIE) in the human atrium. This NIE is augmented in the presence of cAMP-increasing agonists like phosphodiesterase inhibitors (cilostamide, rolipram) or a direct activator of adenylyl cyclase (forskolin). Cantharidin inhibits protein phosphatases 1 and 2A (PP1, PP2A). We hypothesized that cantharidin would attenuate this NIE of R-PIA in the presence of cilostamide or forskolin. During open heart surgery (patients were suffering from severe coronary heart disease), isolated human atrial preparations (HAP) were obtained. These HAP were mounted in organ baths and electrically stimulated (1 Hz). For comparison, we studied isolated electrically stimulated (1 Hz) left atrial preparations (LA) from wild type mice. We noted that R-PIA exerted negative inotropic effects in LA and HAP in the presence of cilostamide or rolipram and forskolin that were attenuated by cantharidin. We hypothesize that R-PIA in the presence of phosphodiesterase inhibitors or forskolin stimulates PP in the human atrium. Hence, R-PIA acts, at least in part, by stimulating PP in HAP.
MeSH
Colforsin, Cantharidin, Receptors, Purinergic P1, Phosphoric Diester Hydrolases, Heart, Rolipram, Adenosine, Phosphoric Monoester Hydrolases, Pharmacology, Phosphoprotein Phosphatases, Phosphodiesterase Inhibitors