家兔Oddi括约肌NOS阳性神经元的分布及其对该括约肌肌电的影响

目的研究家兔Oddi括约肌 (sphincterofOddi,SO)中一氧化氮合酶 (nitricoxidesynthase,NOS)阳性神经元的分布及其对SO肌电的影响。方法应用黄递酶组织化学法 ,观察家兔SO中NOS阳性神经元和其纤维的分布 ;应用电生理学方法 ,观察NOS抑制剂NG 硝基 L 精氨酸 (NG nitro L arginine ,L NNA)及一氧化氮前体L 精氨酸对SO肌电活动的影响。结果在SO的近胆总管侧 ,阳性神经元和神经纤维均明显多于SO的近十二指肠乳头端。根据细胞大小、形态不同 ,NOS阳性神经细胞可分为两种 :一种神经元胞体较大、突起较多、染色较深 ,主要分布于SO的环肌和纵肌之间 ,并且可见由众多NOS阳性神经元所组成的神经节 ;另一种为胞体较小、着色较浅、只有 1～ 2个突起的神经元 ,仅偶见于粘膜下层。NOS阳性神经纤维位于SO各层 ,其中环肌层最丰富。局部灌注L NNA 2 0 0 μg/(kg·min) ,SO肌电活动的振幅明显增大 (P <0 .0 1) ,肌电的频率无明显变化 (P >0 .0 5 ) ;这种作用可被L 精氨酸反转。表明抑制NO合成 ,可引起SO时相性收缩活动增强。结论大量NOS阳性神经元分布于肌间神经丛 ,少量偶见于粘膜下神经丛 ,NO是家兔SO的一种重要抑制性神经递质。

DISTRIBUTION OF NITRIC OXIDE SYNTHASE CONTAINING NEURONS IN THE SPHINCTER OF ODDI AND THE EFFECT OF THESE NEURONS ON THE MYOELECTRIC ACTIVITY OF THE SPHINCTER OF RABBIT

ObjectiveTo clarify the distribution of nitric oxide synthase (NOS) containing neurons in the sphincter of Oddi (SO) and the effect of these neurons on the myoelectric activity of SO. MethodsUsing nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemical method,the distribution of NOS positive neurons was investigated. Using electrophysiological method, the effect of N G-nitro-L-arginine (L-NNA) and L-arginine (L-arg) on the myoelectric activity of SO was investigated. ResultsThe numbers of NADPH-d positive neurons and nerve fibers in areas close to the common bile duct are more than that in areas close to the duodenal papilla. NADPH-d positive neurons could be distinguished into two types on the basis of size, shape and location. Most of the neurons located between the circular and longitudinal muscles of the sphincter of Oddi are large in size with many processes and showed strong activity for the enzyme. The nerve fibers with NADPH-d activity were observed in all layers, chiefly in circular muscle layers. L-NNA perfused alone increased motility of sphincter of Oddi. L-arginine reversed the increase. ConclusionNO may be a very important inhibitory transmitter molecule in the sphincter of Oddi of rabbits, and baseline sphincter of Oddi motility regulation involves in the generation of NO from L-arginine.