Milusheva Elisaveta A, Kuneva Vjara I, Itzev Dimitar E, Kortezova Nadejda I, Sperlagh Beata, Mizhorkova Zlatka N
Department Vegetative regulations, Institute of Physiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., BL. 23, 1113 Sofia, Bulgaria.
Brain Res Bull. 2005 Aug 15;66(3):229-34. doi: 10.1016/j.brainresbull.2005.05.011.
Glutamate was found to be an excitatory neurotransmitter in the enteric nervous system. Although several lines of evidence indicate a role of glutamate in the regulation of gut motility and secretion the physiological significance of glutamatergic transmission is not clear yet. We studied the effect of glutamate on [3H]acetylcholine release and nicotinamide adenine dinucleotide phosphate-diaphorase staining in longitudinal muscle strips with attached myenteric plexus of guinea pig ileum. L-glutamate (100 microM) significantly enhanced both the evoked [3H]acetylcholine release and the optical density of nicotinamide adenine dinucleotide phosphate-diaphorase positive neurones, i.e. the intensity of staining. The non-competitive N-methyl-D-aspartate receptor antagonist MK-801 (3 microM) abolished the stimulatory effect of L-glutamate on acetylcholine efflux. Similarly, the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine (100 microM) significantly reduced the effect of L-glutamate on [3H]acetylcholine release and nicotinamide adenine dinucleotide phosphate-diaphorase staining. Our data suggest that endogenous nitric oxide seems to mediate the stimulatory effect of glutamate on acetylcholine release from guinea pig myenteric neurons.
谷氨酸被发现是肠神经系统中的一种兴奋性神经递质。尽管有几条证据表明谷氨酸在调节肠道运动和分泌中起作用，但谷氨酸能传递的生理意义尚不清楚。我们研究了谷氨酸对豚鼠回肠带肌间神经丛的纵肌条中[3H]乙酰胆碱释放和烟酰胺腺嘌呤二核苷酸磷酸 - 黄递酶染色的影响。L - 谷氨酸（100微摩尔）显著增强了诱发的[3H]乙酰胆碱释放以及烟酰胺腺嘌呤二核苷酸磷酸 - 黄递酶阳性神经元的光密度，即染色强度。非竞争性N - 甲基 - D - 天冬氨酸受体拮抗剂MK - 801（3微摩尔）消除了L - 谷氨酸对乙酰胆碱流出的刺激作用。同样，一氧化氮合酶抑制剂N（ω） - 硝基 - L - 精氨酸（100微摩尔）显著降低了L - 谷氨酸对[3H]乙酰胆碱释放和烟酰胺腺嘌呤二核苷酸磷酸 - 黄递酶染色的影响。我们的数据表明，内源性一氧化氮似乎介导了谷氨酸对豚鼠肌间神经元乙酰胆碱释放的刺激作用。
