Jenkinson K M, Reid J J, Rand M J
Department of Pharmacology, University of Melbourne, Victoria, Australia.
Eur J Pharmacol. 1995 Mar 6;275(2):145-52. doi: 10.1016/0014-2999(94)00762-v.
In longitudinal strips of rat gastric fundus, hydroxocobalamin (30 microM) significantly reduced relaxations to sodium nitroprusside (100 nM), nitric oxide (NO; 5 microM) and S-nitrosocysteine (3 microM), whereas responses to non-adrenergic, non-cholinergic (NANC) nerve stimulation were only slightly reduced. The stimulation-induced relaxations were markedly reduced by the NO synthase inhibitor NG-nitro-L-arginine (100 microM). Hydroxocobalamin (30 microM) enhanced relaxations to S-nitrosoglutathione (1 and 3 microM), and had no effect on responses to vasoactive intestinal polypeptide (1 nM). Haemoglobin (10 microM) significantly reduced relaxations to sodium nitroprusside, NO, S-nitrosocysteine and S-nitrosoglutathione, but did not affect responses to NANC nerve stimulation or vasoactive intestinal polypeptide. The results suggest that hydroxocobalamin and haemoglobin can differentiate between exogenous and neuronally released NO, and that the transmitter released from nitrergic nerves in the rat gastric fundus is not free NO or the nitrosothiols, S-nitrosocysteine and S-nitrosoglutathione.
在大鼠胃底纵行肌条中，羟钴胺素（30微摩尔）显著降低了对硝普钠（100纳摩尔）、一氧化氮（NO；5微摩尔）和S - 亚硝基半胱氨酸（3微摩尔）的舒张反应，而对非肾上腺素能、非胆碱能（NANC）神经刺激的反应仅略有降低。刺激诱导的舒张反应被一氧化氮合酶抑制剂NG - 硝基 - L - 精氨酸（100微摩尔）显著降低。羟钴胺素（30微摩尔）增强了对S - 亚硝基谷胱甘肽（1和3微摩尔）的舒张反应，并且对血管活性肠肽（1纳摩尔）的反应没有影响。血红蛋白（10微摩尔）显著降低了对硝普钠、NO、S - 亚硝基半胱氨酸和S - 亚硝基谷胱甘肽的舒张反应，但不影响对NANC神经刺激或血管活性肠肽的反应。结果表明，羟钴胺素和血红蛋白可以区分外源性和神经释放的NO，并且大鼠胃底中从含氮能神经释放的递质不是游离的NO或亚硝基硫醇、S - 亚硝基半胱氨酸和S - 亚硝基谷胱甘肽。
