Tracing Study on Neuroaxis of Medial Rectus Muscle in the Brain Stem of the White Rat

To clarify neuronal connection of the medial rectus muscle at brain stem, Bartha strain of the psecudorabies virus(PRV-Ba) and cholera toxin-horeserdish peroxidase(CT-HRP) was injected into medial rectus muscle of the rat. About 84 hours after PRV or CT-HRP injection, the brain was removed and processed immunohistochemical stain for PRV-Ba and neurohistochemical stain for CT-HRP using tetramethyl benzidine. The CT-HRP positive reaction was only present in ipsilateral oculomotor nucleus, contralateral abducence nucleus and bilaterally in rostral interstitial nucleus of medial longitudinal fasciculus, olivary pretectal nucleus, medial and superior vestibular nucleus, nucleus prepositus hypoglossi, prerubral field, nucleus Darkschewitsch, lateral substantia nigra, terminal nucleus of accessory nucleus, dorsal raphenucleus, locus ceruleus and pontime reticular formation. This study confirmed that both oculomotor nucleus and abducence nucleus were connected with each other through the medial longitudinal fasciculus, and neuronal connection of the medial rectus muscle in the rat brain stem.

Comparison between CT-HRP and Bartha Strain of Pseudorabies Virus as a Neurotracer in the Rat Visual System

To investigate the applicability of the Bartha strain of pseudorabies virus(PRV-Ba) as a neurotracer in the visual system, we performed immunohistochemical study of the rat brain after intravitreal injection of the PRV-Ba. Cholera toxin-horseradish peroxidase(CT-HRP), a well known neurotracer, was also injected into the vitreous cavity for comparison. After given survival time the brain was removed and processed immunohistochemical stain for PRV-Ba and neurohistochemical stain for CT-HRP. The CT-HRP positive reactions were observed almost contralaterally in optic chiasm, optic tract, suprachiasmatic nucleus(SCN), olivary pretectal nucleus(OPT), all three subdivision of lateral geniculate body, superficial gray layer and optic layer of superior colliculus and medial, lateral, dorsal terminal nucleus of accessory optic tract. PRV-Ba immunopositive reaction was observed in SCN and OPT, but not in nerve fiber system and dorsal lateral geniculate body. Also PRV-Ba positive cells were distributed mainly in intermediate layer and weakly distributed in superficial layer of the superior colliculus. This study suggests that PRV-Ba is not a useful neurotracer in studying the visual system of the rat.

LOCALIZATION OF MOTOR NEURONS IN THE OCULOMOTOR NUCLEUS INNERVATING THE INFERIOR OBLIQUE MUSCLE AND THEIR DENDRITIC ARCHITECTURE IN THE RABBIT——A STUDY USING CT-HRP / 解剖学报

The localization of the neurons which control the inferior oblique muscle in the oculomotor nucleus and their dendritic architecture were studied by injecting the conjugated cholera toxin-horseradish peroxidase (CT-HRP) into the inferior oblique muscle of 7 rabbits.The oculomotor nucleus could be divided into oral, middle and caudal parts. The middle part was further divided into dorsomedial and ventrolateral parts, and the caudal part divided into dorsal and ventral parts. The labeled neurons innervating the inferior oblique muscle were mainly distributed ipsilaterally and occupying two thirds. of the rostrocaudal extent of the oculomotor nucleus, a few were scattered contralaterally.The labeled cells were found in the dorsomedial part of the nucleus orally, and shifted in successive caudal sections to the medial and then to the ventral part. No labeled cells in the oral and caudal ends of the nucleus could be identified.The dendritic branches of the labeled neurons covered the whole nucleus, but densest in its dorsomedial part. Many of them extended beyond the boundary of the nucleus into the central gray matter dorsally, some even approacheding the aqueduct, or through the medial longitudinal fasciculus into the reticular formation laterally and ventrally. A few dendrites crossed the midline into the contralateral nucleus. Therefore the receptive field of the oculomotor nucleus is presumably much larger than the area of the nucleus itself.