Influence of model melanoidins on calcium‐dependent transport mechanisms in smooth muscle tissue

Abstract

Melanoidins obtained from L-arginine and D-glucose (MW > 3500 Da) were tested for their ability to influence the contractility of gastric smooth muscles. A study within the range 0.1-10 mg/mL revealed that at low concentrations, the melanoidins provoked concentration-dependent contraction, whereas a muscle relaxation was registered at high concentrations. The contraction was preceded by changes in the calcium membrane current as measured by single sucrose-gap method and significantly attenuated by the calcium channel blockers D-600 and nifedipine. Measurements with Ca(2+)-selective electrode showed that the melanoidins decreased the concentration of ionized Ca(2+ )in tissue bath in concentration-dependent manner. Experiments carried out in solutions with lower than normal Ca(2+) concentration and using melanoidins preliminary saturated with Ca(2+ )confirmed that the calcium chelation by melanoidins was a key contributing cause for the development of relaxant response. The results obtained showed that the melanoidins could influence the contractility of smooth muscles through at least two pathways: at low concentrations they caused depolarization and activation of L-type calcium channels, stimulated the Ca(2+ )influx, and provoked contraction, whereas at high concentrations calcium binding by melanoidins led to significant depletion of extracellular calcium ions and contributed to the relaxation process observed.

Drug-Delivery Silver Nanoparticles: A New Perspective for Phenindione as an Anticoagulant

“…It also has the advantage of bringing the effects of the drugs under research closer to how they would act in the body by allowing for the calculation of important pharmacological variables while retaining tissue function [ 122 ]. Previously [ 123 , 124 , 125 , 126 , 127 ], we applied the isolated tissue bath for ex vivo SM activity investigation of different compounds. Thus, we applied the same technique to the exogenous administration of 5 × 10 −5 mol/L PID-loaded Ag NPs (n = 7), compared to Ag NPs (n = 6) and PID only (n = 6).…”

Ex Vivo and In Vivo Study of Some Isoquinoline Precursors

“…Another advantage is that retaining tissue function permits calculation of important pharmacological variables that are more meaningful in a tissue vs. a cellular setting; it comes closer to how the drugs examined would work in the body as a whole [21]. Previously [22][23][24][25][26], the isolated tissue bath was applied for ex vivo SM activity investigation of different compounds, including isoquinoline derivatives. Thus, we applied the same technique to the technique reported in this article with N-(1-(3,4-dimethoxyphenyl)propan-2-yl) amides.…”

New biological properties of coffee melanoidins

“…Some melanoidins evoked contraction while others induced muscle relaxation. 17 In some cases the type of effect on smooth muscles is concentrationdependent 16 suggesting that different mechanisms are being involved with the increase in melanoidin concentration.…”

“…Nevertheless this research is indicative of the potential of coffee melanoidins to inuence some chemical and biochemical processes during their transit through the gastro-intestinal tract. In previous studies 16,17 we supposed that some of the biological effects might also result from activation of cell surface receptors. Binding of molecules to the receptors triggers a cascade of intracellular signaling pathways and leads to physiological responses.…”