Lefebvre R A, Smits G J
Heymans Institute of Pharmacology, University of Gent Medical School, Belgium.
Naunyn Schmiedebergs Arch Pharmacol. 1998 Jun;357(6):671-6. doi: 10.1007/pl00005223.
The influence of pregnancy on the role of nitric oxide (NO) in gastric emptying and in non-adrenergic non-cholinergic (NANC) relaxation was studied in rats. The gastric emptying of a non-nutrient liquid solution and of polysterene beads was studied in non-pregnant (NP), 6 to 7 days pregnant (P7) and 18 to 20 days pregnant (P20) rats. Longitudinal muscle strips of the gastric fundus and circular muscle strips of the pylorus were isolated from NP and P20 rats and NANC relaxations were induced by electrical field stimulation. The gastric emptying of the liquid meal was significantly increased in P20 rats as compared to NP and P7 rats. In NP rats, NG-nitro-L-arginine methyl ester (L-NAME) dose-dependently (50-150 mg/kg i.p.) reduced the gastric liquid emptying; the inhibitory effect of 100 mg/kg L-NAME i.p. was prevented by 400 mg/kg i.p. L-arginine and was mimicked by 100 mg/kg NG-monomethyl-L-arginine (L-NMMA). The percentage inhibition of the liquid emptying by L-NAME did not differ between the 3 groups, except for the dose of 150 mg/kg i.p. where it was significantly lower in P20 rats. The gastric emptying of beads was 54% in NP, 36% in P7 and 69% in P20 rats but these values were not significantly different illustrating the great variability. The inhibitory effect of L-NAME (25 and 100 mg/kg i.p.) on the emptying of beads did not differ between the 3 groups. As evaluated in NP rats, the inhibitory effect of L-NAME on the gastric emptying of the beads was not prevented by L-arginine nor mimicked by L-NMMA. Electrical field stimulation in NANC conditions induced frequency-dependent relaxations in the fundus strips and relaxations followed by rebound contractions in the pyloric strips. These electrically induced NANC relaxations and their reduction by 3x 10(-4) M L-NAME were not different between NP and P20 rats. It can be concluded that no evidence for a regulatory role of NO in the gastric emptying of the beads was found, and that the nitrergic contribution to the gastric emptying of liquids and to the fundic and pyloric NANC relaxations was not influenced by pregnancy in rats.
研究了妊娠对一氧化氮（NO）在大鼠胃排空及非肾上腺素能非胆碱能（NANC）舒张中作用的影响。在未孕（NP）、妊娠6至7天（P7）和妊娠18至20天（P20）的大鼠中，研究了非营养性液体溶液和聚苯乙烯珠的胃排空情况。从NP和P20大鼠分离出胃底纵行肌条和幽门环行肌条，通过电场刺激诱导NANC舒张。与NP和P7大鼠相比，P20大鼠的液体餐胃排空显著增加。在NP大鼠中，NG-硝基-L-精氨酸甲酯（L-NAME）剂量依赖性地（腹腔注射50 - 150 mg/kg）降低胃液体排空；腹腔注射100 mg/kg L-NAME的抑制作用可被腹腔注射400 mg/kg L-精氨酸预防，并被100 mg/kg NG-单甲基-L-精氨酸（L-NMMA）模拟。除腹腔注射150 mg/kg剂量时P20大鼠显著较低外，L-NAME对液体排空的抑制百分比在3组之间无差异。NP大鼠中珠的胃排空率为54%，P7大鼠为36%，P20大鼠为69%，但这些值无显著差异，说明变异性很大。L-NAME（腹腔注射25和100 mg/kg）对珠排空的抑制作用在3组之间无差异。如在NP大鼠中评估的那样，L-NAME对珠胃排空的抑制作用既未被L-精氨酸预防，也未被L-NMMA模拟。在NANC条件下的电场刺激在胃底肌条中诱导频率依赖性舒张，在幽门肌条中诱导舒张后出现反跳收缩。这些电诱导的NANC舒张及其被3×10⁻⁴ M L-NAME的抑制在NP和P20大鼠之间无差异。可以得出结论，未发现NO在珠胃排空中有调节作用的证据，并且大鼠妊娠不影响氮能对液体胃排空以及胃底和幽门NANC舒张的贡献。
