Basal release of 6-cyanodopamine from rat isolated vas deferens and its role on the tissue contractility.

6-Cyanodopamine is a novel catecholamine released from rabbit isolated heart. However, it is not known whether this catecholamine presents any biological activity. Here, it was evaluated whether 6-cyanodopamine (6-CYD) is released from rat vas deferens and its effect on this tissue contractility. Basal release of 6-CYD, 6-nitrodopamine (6-ND), 6-bromodopamine, 6-nitrodopa, and 6-nitroadrenaline from vas deferens were quantified by LC-MS/MS. Electric-field stimulation (EFS) and concentration-response curves to noradrenaline, adrenaline, and dopamine of the rat isolated epididymal vas deferens (RIEVD) were performed in the absence and presence of 6-CYD and /or 6-ND. Expression of tyrosine hydroxylase was assessed by immunohistochemistry. The rat isolated vas deferens released significant amounts of both 6-CYD and 6-ND. The voltage-gated sodium channel blocker tetrodotoxin had no effect on the release of 6-CYD, but it virtually abolished 6-ND release. 6-CYD alone exhibited a negligible RIEVD contractile activity; however, at 10 nM, 6-CYD significantly potentiated the noradrenaline- and EFS-induced RIEVD contractions, whereas at 10 and 100 nM, it also significantly potentiated the adrenaline- and dopamine-induced contractions. The potentiation of noradrenaline- and adrenaline-induced contractions by 6-CYD was unaffected by tetrodotoxin. Co-incubation of 6-CYD (100 pM) with 6-ND (10 pM) caused a significant leftward shift and increased the maximal contractile responses to noradrenaline, even in the presence of tetrodotoxin. Immunohistochemistry revealed the presence of tyrosine hydroxylase in both epithelial cell cytoplasm of the mucosae and nerve fibers of RIEVD. The identification of epithelium-derived 6-CYD and its remarkable synergism with catecholamines indicate that epithelial cells may regulate vas deferens smooth muscle contractility.

A collagen I derived matricryptin increases aorta vascular wall remodeling after induced thrombosis in mouse.

Matricryptins are collagen fragments proteolytically released from the extracellular matrix (ECM) with biological activity that can regulate several processes involved in ECM remodeling. Vessel wall matrix reorganization after lesion is important to the recovery of vascular function. This study aimed to analyze the effect of the peptide p1158/59 (Lindsey, 2015) on thrombosis, neointimal formation, and vascular remodeling of C57BL6 mice abdominal aorta. We used a FeCl3 induced vascular injury mice model and analyzed thrombus size, neointima formation, gelatinase activities in situ, re-endothelization, and collagen fibers organization on the arterial wall using polarization microscopy. As result, we observed that 2 days after injury the treatment with p1158/59 increased thrombus size and gelatinase activity, vascular lesion and it did not recover the endothelium loss induced by the chemical injury. We also observed that the peptide increased neointima growth and collagen birefringence, indicating collagen fibers reorganization. It also promoted increased re-endothelization and decreased activity of gelatinases 14 days after injury. Thus, we conclude that the peptide p1158/59 impaired the initial thrombosis recovery 2 days after injury but was able to induce vascular ECM remodeling after 14 days, improving vessel re-endothelization, collagen fibers deposition, and organization.