Dataset Information

N-Salicyloyltryptamine, an N-Benzoyltryptamine Analogue, Induces Vasorelaxation through Activation of the NO/sGC Pathway and Reduction of Calcium Influx.

ABSTRACT: Benzoyltryptamine analogues act as neuroprotective and spasmolytic agents on smooth muscles. In this study, we investigated the ability of N-salicyloyltryptamine (STP) to produce vasorelaxation and determined its underlying mechanisms of action. Isolated rat mesenteric arteries with and without functional endothelium were studied in an isometric contraction system in the presence or absence of pharmacological inhibitors. Amperometric experiments were used to measure the nitric oxide (NO) levels in CD31+ cells using flow cytometry. GH3 cells were used to measure Ca2+ currents using the whole cell patch clamp technique. STP caused endothelium-dependent and -independent relaxation in mesenteric rings. The endothelial-dependent relaxations in response to STP were markedly reduced by L-NAME (endothelial NO synthase-eNOS-inhibitor), jHydroxocobalamin (NO scavenger, 30 µM) and ODQ (soluble Guanylyl Cyclase-sGC-inhibitor, 10 µM), but were not affected by the inhibition of the formation of vasoactive prostanoids. These results were reinforced by the increased NO levels observed in the amperometric experiments with freshly dispersed CD31+ cells. The endothelium-independent effect appeared to involve the inhibition of voltage-gated Ca2+ channels, due to the inhibition of the concentration-response Ca2+ curves in depolarizing solution, the increased relaxation in rings that were pre-incubated with high extracellular KCl (80 mM), and the inhibition of macroscopic Ca2+ currents. The present findings show that the activation of the NO/sGC/cGMP pathway and the inhibition of gated-voltage Ca2+ channels are the mechanisms underlying the effect of STP on mesenteric arteries.

SUBMITTER: Veras RC

PROVIDER: S-EPMC6017111 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature

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N-Salicyloyltryptamine, an N-Benzoyltryptamine Analogue, Induces Vasorelaxation through Activation of the NO/sGC Pathway and Reduction of Calcium Influx.

Veras Robson Cavalcante RC Silva Darizy Flávia DF Bezerra Lorena Soares LS Assis Valéria Lopes de VL Vasconcelos Walma Pereira de WP Alustau Maria do Carmo MDC Albuquerque José George Ferreira de JGF Furtado Fabíola Fialho FF Araújo Islania Giselia de Albuquerque IGA Azevedo Fátima de Lourdes Assunção Araújo de FLAA Ribeiro Thais Porto TP Barbosa-Filho José Maria JM Gutierrez Stanley Juan Chavez SJC Medeiros Isac Almeida IA

Molecules (Basel, Switzerland) 20180128 2

Benzoyltryptamine analogues act as neuroprotective and spasmolytic agents on smooth muscles. In this study, we investigated the ability of <i>N</i>-salicyloyltryptamine (STP) to produce vasorelaxation and determined its underlying mechanisms of action. Isolated rat mesenteric arteries with and without functional endothelium were studied in an isometric contraction system in the presence or absence of pharmacological inhibitors. Amperometric experiments were used to measure the nitric oxide (NO) ...[more]

PMID: 29382081

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Project description:Background PFI-3 is a small-molecule inhibitor that targets the bromodomains (BRDs) of Brahma-related gene 1 (BRG1). This monomeric compound, which has high selectivity and potent cellular effects, has recently been developed. Although PFI-3 has been reported as a potential therapeutic agent targeting thrombomodulin, its role in the regulation of vascular function remains unknown. Therefore, we aimed to investigate the impact of PFI-3 on arterial vessel tone. Methods A microvascular tension measurement device (DMT) was utilized to identify alterations in vascular tension within the mesenteric artery. To detect variations in cytosolic [Ca2+]i, a Fluo-3/AM fluorescent probe and fluorescence microscope were employed. Additionally, whole-cell patch clamp techniques were utilized to evaluate the activity of L-type voltage-dependent calcium channels (VDCCs) in cultured arterial smooth muscle cells (A10 cells). Results PFI-3 exerted a dose-dependent relaxation effect on rat mesenteric arteries with both intact and denuded endothelium after phenylephrine (PE)- and high-K+-induced constriction. PFI-3-induced vasorelaxation was not affected by the presence of L-NAME/ODQ or K+ channel blockers (Gli/TEA). PFI-3 abolished Ca2+-induced contraction on endothelium-denuded mesenteric arteries preincubated by PE in Ca2+-free solution. Incubation with TG had no impact on PFI-3-induced vasorelaxation pre-contracted by PE. PFI-3 reduced Ca2+-induced contraction on endothelium-denuded mesenteric arteries pre-incubated by KCl (60 mM) in Ca2+-free solution. PFI-3 declined extracellular calcium influx in A10 cells detected by Fluo-3/AM fluorescent probe and fluorescence microscope. Furthermore, we observed that PFI-3 decreased the current densities of L-type VDCC by whole-cell patch clamp techniques. Conclusions PFI-3 blunted PE and high K+-induced vasoconstriction independent of endothelium on rat mesenteric artery. The vasodilatory effect of PFI-3 may be attributed to its inhibition of VDCCs and receptor-operated calcium channels (ROCCs) on vascular smooth muscle cells (VSMCs).

Project description:Adequate perfusion of the placental vasculature is essential to meet the metabolic demands of fetal growth and development. Lacking neural control, local tissue metabolites, circulating and physical factors contribute significantly to blood flow regulation. Nitric oxide (NO) is a key regulator of fetoplacental vascular tone. Nitrite, previously considered an inert end-product of NO oxidation, has been shown to provide an important source of NO. Reduction of nitrite to NO may be particularly relevant in tissue when the oxygen-dependent NO synthase (NOS) activity is compromised, e.g. in hypoxia. The contribution of this pathway in the placenta is currently unknown. We hypothesised that nitrite vasodilates human placental blood vessels, with enhanced efficacy under hypoxia. Placentas were collected from uncomplicated pregnancies and the vasorelaxant effect of nitrite (10-6-5x10-3?M) was assessed using wire myography on isolated pre-constricted chorionic plate arteries (CPAs) and veins (CPVs) under normoxic (pO2 ?5%) and hypoxic (pO2 ?1%) conditions. The dependency on the NO-sGC-cGMP pathway and known nitrite reductase (NiR) activities was also investigated. Nitrite caused concentration-dependent vasorelaxation in both arteries and veins, and this effect was enhanced by hypoxia, significantly in CPVs (P?<?0.01) and with a trend in CPAs (P?=?0.054). Pre-incubation with NO scavengers (cPTIO and oxyhemoglobin) attenuated (P?<?0.01 and P?<?0.0001, respectively), and the sGC inhibitor ODQ completely abolished nitrite-mediated vasorelaxation, confirming the involvement of NO and sGC. Inhibition of potential NiR enzymes xanthine oxidoreductase, mitochondrial aldehyde dehydrogenase and mitochondrial bc1 complex did not attenuate vasorelaxation. This data suggests that nitrite may provide an important reservoir of NO bioactivity within the placenta to enhance blood flow when fetoplacental oxygenation is impaired, as occurring in pregnancy diseases such as pre-eclampsia and fetal growth restriction.

Dataset Information

N-Salicyloyltryptamine, an N-Benzoyltryptamine Analogue, Induces Vasorelaxation through Activation of the NO/sGC Pathway and Reduction of Calcium Influx.

Publications

N-Salicyloyltryptamine, an N-Benzoyltryptamine Analogue, Induces Vasorelaxation through Activation of the NO/sGC Pathway and Reduction of Calcium Influx.

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