Furness John B, Alex George, Clark Melanie J, Lal Varsha V
Department of Anatomy and Cell Biology, University of Melbourne, Parkville, VIC 3010, Australia.
Anat Rec A Discov Mol Cell Evol Biol. 2003 Jun;272(2):475-83. doi: 10.1002/ar.a.10064.
Four types of neurons have previously been identified by neurochemical markers in the submucosal ganglia of the guinea-pig small intestine, and functional roles have been ascribed to each type. However, morphological differences among the classes have not been determined, and there is only partial information about their projections within the submucosa. In the present work, we used intracellular microelectrodes to fill neurons of each type with biocytin, which was then converted to a permanent dye, so that the shapes of the neurons could be determined and their projections within the submucosa could be followed. Cell bodies of noncholinergic secretomotor/ vasodilator neurons had Dogiel type I morphology. These neurons, which are vasoactive intestinal peptide immunoreactive, had single axons that ran through many ganglia without providing terminals around other neurons. Cholinergic secretomotor neurons with neuropeptide Y immunoreactivity had Stach type IV morphology, and cholinergic secretomotor/vasodilator neurons had stellate cell bodies. The axons of these two types ran short distances in the plexus and did not innervate other submucosal neurons. Neurons of the fourth type, intrinsic primary afferent neurons, had cell bodies with Dogiel type II morphology and their processes supplied networks of varicose processes around other nerve cells. It is concluded that each functionally defined type of submucosal neuron has a characteristic morphology and that intrinsic primary afferent neurons synapse with secretomotor neurons to form monosynaptic secretomotor reflex circuits.
先前已通过神经化学标记物在豚鼠小肠黏膜下神经节中鉴定出四种类型的神经元，并赋予了每种类型相应的功能作用。然而，这些类型之间的形态学差异尚未确定，并且关于它们在黏膜下层内的投射仅有部分信息。在本研究中，我们使用细胞内微电极用生物素填充每种类型的神经元，然后将其转化为永久性染料，以便能够确定神经元的形状并追踪它们在黏膜下层内的投射。非胆碱能分泌运动/血管舒张神经元的细胞体具有多极I型形态。这些神经元具有血管活性肠肽免疫反应性，有单根轴突穿过许多神经节，且不在其他神经元周围提供终末。具有神经肽Y免疫反应性的胆碱能分泌运动神经元具有斯塔克IV型形态，胆碱能分泌运动/血管舒张神经元具有星状细胞体。这两种类型的轴突在神经丛中走行较短距离，并不支配其他黏膜下神经元。第四种类型的神经元，即内在初级传入神经元，其细胞体具有多极II型形态，其突起在其他神经细胞周围形成曲张突起网络。得出的结论是，黏膜下神经元的每种功能定义类型都具有特征性形态，并且内在初级传入神经元与分泌运动神经元形成突触以形成单突触分泌运动反射回路。
