Radcliffe B C, Nance S H, Deakin E J, Roediger W E
Am J Physiol. 1987 Aug;253(2 Pt 1):G246-52. doi: 10.1152/ajpgi.1987.253.2.G246.
The disposition of intravenously or luminally administered nitrite across the colonic mucosa and its effect on ion movement into or from the colon was assessed in anesthetized Porton rats using the isolated colon instilled either with sodium chloride (120 mM) or sodium chloride (80 mM) with sodium butyrate (40 mM). Ionic changes in the colon after intravenous injection of 10 mumol NaNO2 were compared with those occurring after injection of 10 mumol NaCl. After intravenous administration of nitrite, both nitrite and nitrate appeared in the colonic instillate in a ratio of 1:1. Nitrite increased chloride absorption (110%) and bicarbonate production (20%) when 40 mM butyrate was included in the instillate. Net sodium absorption, measured in the whole colon, was unchanged. Intravenous nitrite had no effect on ionic movement in the absence of butyrate. When NaNO2 (100 microM) was included luminally with the sodium chloride-butyrate instillate, bicarbonate production rate increased (25%), but sodium and chloride absorption were unaffected. Nitrite concentration in the instillate decreased during the 40-min experimental period at a rate of 0.275 nmol X min-1 X cm-2, and nitrate appeared at a rate of 0.037 nmol X min-1 X cm-2. We conclude that nitrate stimulates bicarbonate production in the colon, probably by stimulating the oxidation of butyrate, the main source of CO2 generation by the colonic mucosa.
在麻醉的波顿大鼠中，使用灌流有氯化钠（120 mM）或氯化钠（80 mM）与丁酸钠（40 mM）的离体结肠，评估静脉内或腔内给予的亚硝酸盐在结肠黏膜中的分布及其对离子进出结肠运动的影响。将静脉注射10 μmol亚硝酸钠后结肠中的离子变化与注射10 μmol氯化钠后发生的离子变化进行比较。静脉给予亚硝酸盐后，亚硝酸盐和硝酸盐以1:1的比例出现在结肠灌流液中。当灌流液中含有40 mM丁酸盐时，亚硝酸盐增加了氯离子吸收（110%）和碳酸氢盐生成（20%）。在整个结肠中测量的钠净吸收没有变化。在没有丁酸盐的情况下，静脉注射亚硝酸盐对离子运动没有影响。当100 μM亚硝酸钠与氯化钠-丁酸盐灌流液一起腔内给药时，碳酸氢盐生成速率增加（25%），但钠和氯的吸收不受影响。在40分钟的实验期间，灌流液中亚硝酸盐浓度以0.275 nmol·min⁻¹·cm⁻²的速率下降，硝酸盐以0.037 nmol·min⁻¹·cm⁻²的速率出现。我们得出结论，硝酸盐可能通过刺激丁酸盐的氧化来刺激结肠中的碳酸氢盐生成，丁酸盐是结肠黏膜产生二氧化碳的主要来源。
