Effects of combined pre- and post-natal protein deprivation on the myenteric plexus of the esophagus of weanling rats:A histochemical,quantitative and ultrastructural study

AIM: To evaluate the effects of protein deprivation on the myenteric plexus of the esophagus of weanling rats. METHODS: Pregnant female Wistar rats were divided into 2 groups: nourished (N),receiving normal diet,and undernourished (D),receiving a protein-deprived diet,which continued after birth. At twenty-one days of age,13 esophagi from each group were submitted to light microscopy and morphometrical analysis employing the NADH diaphorase,NADPH diaphorase and acetylcholinesterase techniques. Three other esophagi from each group were evaluated with transmission electron microscopy (TEM). RESULTS: In both the NADH- and the NADPH-reactive mounts,the neurons of the N mounts were more intensely stained,while in the D esophagi only the larger neurons were reactive. Many myenteric neurons of N were intensely reactive for AChE activity but only a few neurons of D exhibited these aspects. Ultrastructural analysis revealed that the granular reticulum of N showed large numbers of ribosomes aligned on the outer surface of its regularly arranged membrane while the ribosomes of D were disposed in clusters. The chromatin was more homogeneously scattered inside the neuron nucleus of N as well as the granular component of the nucleolus was evidently more developed in this group. Statistically significant differences between N and D groups were detected in the total estimated number of neurons stained by the NADPH technique. CONCLUSION: The morphological and quantitative data shows that feeding with protein-deprived diet in 21-d old rats induces a delay in the development of the myenteric neurons of the esophagus.

Effects of perinatal protein deprivation and recovery on esophageal myenteric plexus

AIM:To evaluate effects of preand postnatal protein deprivation and postnatal recovery on the myenteric plexus of the rat esophagus. METHODS: Three groups of young Wistar rats (aged 42 d) were studied: normalfed (N42), proteindeprived (D42), and proteinrecovered (R42). The myenteric neurons of their esophagi were evaluated by histochemical reactions for nicotinamide adenine dinucleotide (NADH), nitrergic neurons (NADPH)diaphorase and acetylcholinesterase (AChE), immunohistochemical reaction for vasoactive intestinal polypeptide (VIP), and ultrastructural analysis by transmission electron microscopy.RESULTS: The cytoplasms of large and medium neurons from the N42 and R42 groups were intensely reactive for NADH. Only a few large neurons from the D42 group exhibited this aspect. NADPH detected in the D42 group exhibited low reactivity. The AChE reactivity was diffuse in neurons from the D42 and R42 groups. The density of large and small varicosities detected by immunohistochemical staining of VIP was low in ganglia from the D42 group. In many neurons from the D42 group, the double membrane of the nuclear envelope and the perinuclear cisterna were not detectable. NADH and NADPH histochemistry revealed no group differences in the prof ile of nerve cell perikarya (ranging from 200 to 400 μm2).CONCLUSION: Protein deprivation causes a delay in neuronal maturation but postnatal recovery can almost completely restore the normal morphology of myenteric neurons.

豚鼠胃肠壁内神经丛的能量代谢的酶和基本物质的组织化学观察

本文研究了正常成年豚鼠胃肠壁内神经丛神经元(简称肠神经元)的镁激活的三磷酸腺苷酶(Mg^(++)-ATPase)、钙激活的三磷酸腺芏酶(Ca^(++)-ATPase)、细胞色素氧化酶(CCO)、琥珀酸脱氢酶(SDH)、乳酸脱氢酶(LDH)、葡萄糖-6-磷酸脱氢酶(G6 PDH)和葡萄糖-6-磷酸酶(G 6Pase),并对糖类、蛋白质、脂类和核酸做了观察。除光镜的半定量观察外,并用显微光度计对两种ATPase做了定量测量。光镜的半定量结果和显微光度计测得的数据经计算机做了统计学处理。本文的结果表明,肠神经元具有上述各种酶活性,提示神经元与这些酶有关的代谢活跃。但粘膜下丛与肠肌丛酶活性差异显著,前者SDH活性较强,后者LDH、G6 PDH和两种ATPase活性较强。据此推测,两神经丛神经元的主要糖代谢方式、能量代谢以及机能活跃程度有明显的差别。此外,胃肠各段肠肌丛酶活性强度不一,十二指肠和近端结肠各种酶活性最强,盲肠最弱。本文的结果表明,肠神经元的代谢和功能确有相当的差别,但酶活性的差异同神经元类型的关系如何,有待继续研究。

Quantitative changes of nitrergic neurons during postnatal development of chicken myenteric plexus

Objective: Information regarding the development of the enteric nervous system(ENS) is important for understanding the functional abnormalities of the gut.Because fertilized chicken eggs provide easy access to embryos,chicken models have been widely used to study embryonic development of myenteric plexus;however,no study has been focused on the postnatal period.The aim of this study was to perform a qualitative and quantitative analysis of the nitrergic neurons in the myenteric plexus of developing chickens in the postnatal period.Methods: Whole-mount preparations of the myenteric plexus were made in 7-d,15-d,and 40-d old(adult) chickens of either sex(n=15).The myenteric plexus was studied after nicotinamide adenine dinucleotide phosphate diaphorase(NADPH-d) histochemistry using light microscopy,digital photography,and Image-Pro Plus 6.0 software.The numbers of positively stained neurons and ganglia were counted in the duodenum,jejunum,ileum,caecum,and colon in the different age groups.Data were expressed as mean±standard deviation(SD),and statistical analysis was performed using a one-way analysis of variance(ANOVA) test.Results: The positively stained neurons showed various morphologies and staining intensities,and formed bead-shaped and U-shaped arrangements in the myenteric plexus.The densities of neurons and ganglia increased with age.However,the number of positive neurons per ganglion increased.The number of NADPH-d-positive neurons was highest in the colon,followed by the ileum,the jejunum,the duodenum,and the caeca in all age groups.Conclusions: Developmental changes in the myenteric plexus of chickens continue in the postnatal period,indicating that the maturation process of the gastrointestinal function is gradual.In addition,no significant difference is happening among different intestinal segments during postnatal development,suggesting that the function of different intestinal segments had been determined after birth.