Endothelin and neonatal capsaicin regulate gastric resistance to injury in BDL rats

Extraction, purification, bioactivity and pharmacological effects of capsaicin: a review

Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide), a well-known vanilloid, which is the main spicy component in chili peppers, showing several biological activities and the potential applications range from food flavorings to therapeutics. Traditional extraction of capsaicin by organic solvents was time-consuming, some new methods such as aqueous two-phase method and ionic liquid extraction method have been developed. During past few decades, an ample variety of biological effects of capsaicin have been evaluated. Capsaicin can be used in biofilms and antifouling coatings due to its antimicrobial activity, allowing it has a promising application in food packaging, food preservation, marine environment and dental therapy. Capsaicin also play a crucial role in metabolic disorders, including weight loss, pressure lowing and insulin reduction effects. In addition, capsaicin was identified effective on preventing human cancers, such as lung cancer, stomach cancer, colon cancer and breast cancer by inducing apoptosis and inhibiting cell proliferation of tumor cells. Previous research also suggest the positive effects of capsaicin on pain relief and cognitive impairment. Capsaicin, the agonist of transient receptor potential vanilloid type 1 (TRPV1), could selectively activate TRPV1, inducing Ca²⁺ influx and related signaling pathways. Recently, gut microbiota was also involved in some diseases therapeutics, but its influence on the effects of capsaicin still need to be deeply studied. In this review, different extraction and purification methods of capsaicin, its biological activities and pharmacological effects were systematically summarized, as well as the possible mechanisms were also deeply discussed. This article will give an updated and better understanding of capsaicin-related biological effects and provide theoretical basis for its further research and applications in human health and manufacture development.

Nitric oxide released from luminal s-nitroso-N-acetylcysteine increases gastric mucosal blood flow

Nitric oxide (NO)-mediated vasodilation plays a key role in gastric mucosal defense, and NO-donor drugs may protect against diseases associated with gastric mucosal blood flow (GMBF) deficiencies. In this study, we used the ex vivo gastric chamber method and Laser Doppler Flowmetry to characterize the effects of luminal aqueous NO-donor drug S-nitroso-N-acetylcysteine (SNAC) solution administration compared to aqueous NaNO2 and NaNO3 solutions (pH 7.4) on GMBF in Sprague-Dawley rats. SNAC solutions (600 μM and 12 mM) led to a rapid threefold increase in GMBF, which was maintained during the incubation of the solutions with the gastric mucosa, while NaNO2 or NaNO3 solutions (12 mM) did not affect GMBF. SNAC solutions (600 μM and 12 mM) spontaneously released NO at 37 °C at a constant rate of 0.3 or 14 nmol·mL-1·min-1, respectively, while NaNO2 (12 mM) released NO at a rate of 0.06 nmol·mL-1·min-1 and NaNO3 (12 mM) did not release NO. These results suggest that the SNAC-induced GMBF increase is due to their higher rates of spontaneous NO release compared to equimolar NaNO2 solutions. Taken together, our data indicate that oral SNAC administration is a potential approach for gastric acid-peptic disorder prevention and treatment.

Blockade of endothelin ET(A), but not thromboxane, receptors offsets the cyclosporine-evoked hypertension and interrelated baroreflex and vascular dysfunctions

The impairment of arterial baroreceptor and vasodilator functions are two major contributors to the hypertensive action of cyclosporine (CSA). In this study, in vivo and in vitro pharmacological studies were performed to investigate whether these effects of CSA are differentially modulated by endothelin and thromboxane signaling. The treatment of rats with CSA (25mg/kg/day i.p.) for 7 consecutive days caused significant increases in blood pressure (BP), attenuated reflex heart rate (HR) responses to vasopressor (phenylephrine, PE) and vasodepressor (sodium nitroprusside, SNP) agents, and reduced cumulative vasorelaxant responses elicited by acetylcholine (Ach, 1×10(-9)-1×10(-5)M) in PE-precontracted isolated aortas. These effects of CSA were blunted after concurrent i.p. administration of atrasentan (selective ETA blocker, 10mg/kg/day), but not terutroban (thromboxane receptor blocker, 10mg/kg/day). Moreover, atrasentan reversed the reductions in aortic protein expression of eNOS caused by CSA whereas terutroban was without effect. We also report that the favorable effect of atrasentan on CSA-evoked impairment in aortic Ach responsiveness disappeared in rats treated simultaneously with L-NAME (NOS inhibitor, 10mg/kg/day) but not BQ 788 (ETB receptor blocker, 0.1mg/kg/day) or indomethacin (cycloxygenase inhibitor, 5mg/kg/day). Together, the data implicate endothelin ETA receptors in baroreflex and vascular derangements which predispose to the hypertensive effect of CSA. Moreover, the facilitation of NOS, but not ETB receptors or cycloxygenase-derived prostanoids, signaling is pivotal for advantageous effect of atrasentan on the aortic CSA-Ach interaction.