Fibrous Connections Between Gigantocellular Reticular Nucleus And Motor Nucleus Of Cranial Nerves In The Rat

Gigantocellular reticular nucleus(NRG) lying in the reticular formation of brainstem hold complex functions. The nucleus evoke some effects, whether on the body movement or on the viscera movements. Electrophysiological and morpholo gical studies have sufficient suggested that the gigantocellular reticular nucleus bring the inhibiting central regulate and control to the body movement. However,the relation between the nucleus and the viscera activities is short of full and systemic information. The experiment wanted to supply the data from the morphology about the other effects of the nucleus.Objective1. To observe the direct fibrous connections between the gigantocellular reticular nucleus and the motor nucleus of cranial nerves in the rat.2. To compare the labeling effect on two tracers which are WGA—HRP(horseradish peroxidase wheat germ agglutinin) and DiI (1,1'-dioctadecyl-3,3,3',3'-tetra-methylindocarbocyanine perchlorate).Methods1. carbon ink was unilaterally innjected into the gigantocellular reticular nucleus of the adult rats by microtransfusing and the slices were made Nissl dyeing ,then it was observed the place injected of NRG was accurate or not. 2. By means of the injection of a small amount of WGA—HRP into the one side of NRG in the adult rats, according to the way of TMB—ST the staining was displayed,then it was watched the place which was injected and tagged in the sections through light microscope.3. The one side of NRG of the adult rats was transfused into DiI,following the steps, brain tissue was need to take out and sections were observed using fluorescence microscope.Results1. common somatic motor nucleus: the retrogradely labeled neuronal cell bodies and anterogradely labeled fibers were found in double sides of both nucleus of oculomotor nerve and nucleus of trochlear nerve,in addition,the number of the labeled cells at the same side was more than those at the other side. The nervous sign was not discovered in the abducens nucleus.There are the labeled cell bodies in double sides of hypoglossal nucleus and fibrous terminal.2. common visceral motor nucleus:the inferior salivatory nucleus and dorsal nucleus of vagus nerve where were saw a small amount of the neurons stained and nerve fibers at double sides. Superior salivatory nucleus was not marked.3. Special visceral motor nucleus:the nucleus of facial nerve,nucleus ambiguous and motor nucleus of trigeminal nerve were found the neuronal cell bodies labeled and fibers at both sides.4. The distribution labeled through WGA—HRP was close to DiI,however, the difference of them was anything labeled by DiI was not seen in inferior salivatory nucleus.the number of the neuronal cells were marked with DiI was less than WGA—HRP as a tracer.Conclusion1.There are fibrous contacts between NRG and mass motor nucleus of cranial nerves in rat, further more, the projections are bidirectional.2.Comparing WGA—HRP with DiI,the labling effect of the former is better than the latter in vivo brain of adult animal.