RT Journal Article SR Electronic A1 Figueroa-Valverde, Lauro A1 Diaz-Cedillo, Francisco A1 Garcia-Cervera, Elodia A1 Gomez, Eduardo Pool A1 Lopez-Ramos, Maria T1 Effect of progesterone-carbachol derivative on perfusion pressure and coronary resistance in isolated rat heart: via activation of the M<sub>2</sub> muscarinic receptor JF Biomedical papers YR 2014 VO 158 IS 1 SP 073 OP 079 DO 10.5507/bp.2012.010 UL https://biomed.papers.upol.cz/artkey/bio-201401-0011.php AB Aim: The present study was designed to investigate the effects of progesterone-carbachol derivative on perfusion pressure and coronary resistance in rats. An additional aim was to identify the molecular mechanisms involved. Methods: The Langendorff model was used to measure perfusion pressure and coronary resistance changes in isolated rat heart after progesterone-carbachol derivative alone and after the following compounds; mifepristone (progesterone receptor blocker), yohimbine (α<sub>2</sub> adreno-receptor antagonist), ICI 118,551 (selective β<sub>2</sub> receptor blocker), atropine (non-selective muscarinic receptor antagonist), methoctramine (antagonist of M<sub>2</sub> receptor) and L-NAME (inhibitor of nitric oxide synthase). Results: The results show that progesterone-carbachol derivative [10<sup>-9</sup> mM] significantly decreased perfusion pressure (P=0.005) and coronary resistance (P=0.006) in isolated rat heart. Additionally, the effect of progesterone-carbachol on perfusion pressure [10<sup>-9</sup> to 10<sup>-4 </sup>mM] was only blocked in the presence of methoctramine and L-NAME. Conclusions: These data suggest that progesterone derivative exert its effect on perfusion pressure via activation of the M<sub>2</sub> muscarinic. In addition, this phenomenon involves stimulation of nitric oxide synthase (NOS).