Takashi Tashiro

Distribution of axons exhibiting both enkephalin- and serotonin-like immunoreactivities in the lumbar cord segments: an immunohistochemical study in the cat

Axons exhibiting both enkephalin- and serotonin-like immunoreactivities were observed by the double immunofluorescence method in the lumbar cord segments of the cat. Double-labeled axons were seen most frequently in laminae I, IIa and the lateral part of lamina V. They were also distributed in other parts of the dorsal horn and lamina X (especially in the dorsal part), but rarely found in laminae VII, VIII and IX. After cervical hemicordotomy the vast majority of double-labeled axons disappeared from the spinal gray ipsilateral to the lesion.

Amygdaloid pathway to the trigeminal motor nucleus via the pontine reticular formation in the rat

The connections of the amygdala with the trigeminal motor nucleus were studied by light and electron microscopy. Horseradish peroxidase (HRP) experiments showed that the pontine reticular formation, ventromedial to the spinal trigeminal nucleus at the level rostral to the genu of the facial nerve, receives fibers from the central nucleus of the amygdala ipsilaterally and sends fibers to the trigeminal motor nucleus contralaterally. Electron microscopic observations were carried out on the pontine reticular formation after electrolytic lesions in the central nucleus of the amygdala and HRP injections into the contralateral trigeminal motor nucleus were made on the same animal. These experiments using the combined degeneration and HRP technique clearly demonstrated that degenerating amygdaloid fibers made synaptic contacts with retrogradely labeled neurons.

Convergence of serotonin-, enkephalin- and substance P-like immunoreactive afferent fibers on single pudendal motoneurons in Onuf's nucleus of the cat: a light microscope study combining the triple immunocytochemical staining technique with the retrograde HRP-tracing method

Convergence of serotonin (5-HT)-, enkephalin (ENK)-, and substance P (SP)-like immunoreactive (LI) afferent fibers on single pudendal motoneurons within Onufs nucleus was demonstrated: pudendal motoneurons were retrogradely labeled with horseradish peroxidase applied to the pudendal nerve. Subsequently, 5-HT-LI fibers were stained by the immunoperoxidase method, and then ENK- and SP-LI fibers were stained by the double immunofluorescence method.

Representation of the main branches of the facial nerve within the facial nucleus of the Japanese monkey (Macaca fuscata).

The facial nucleus of the Japanese monkey was divided cytoarchitectonically into the ventral, medial, intermediate, dorsal and lateral divisions. When horseradish peroxidase (HRP) was applied to the inferior labial, cervical or posterior auricular branch of the facial nerve, HRP-labeled neurons were seen in the lateral, ventral or medial division of the facial nucleus, respectively. After applying HRP to the anterior auricular-zygomatico-orbital branch, labeled neurons were observed mainly in the intermediate and dorsal divisions. HRP applied to the superior labial branch labeled neurons within the dorsal and lateral divisions.

Distribution of axons showing calcitonin gene-related peptide- and/or substance P-like immunoreactivity in the sensory trigeminal nuclei of the cat.

Distribution of axons with calcitonin gene-related peptide (CGRP)-like and/or substance P (SP)-like immunoreactivity (LI) within the sensory trigeminal nuclei was examined in the cat before and after trigeminal rhizotomy. Axons with CGRP-LI or SP-LI were seen throughout the principal sensory trigeminal nucleus (Vp) and spinal trigeminal nuclei, including the medullary dorsal horn (MDH). They were densely distributed particularly in the dorsolateral part of the dorsal subnucleus of the Vp, ventromedial marginal zone of the ventral subnucleus of the Vp, dorsomedial and ventromedial parts of the oral spinal trigeminal nucleus, ventromedial and lateral marginal zones of the interpolar spinal trigeminal nucleus, and lamina I, outer part of lamina II and lamina V of the MDH. Most of the CGRP-LI axons exhibited SP-LI, while many SP-LI axons did not show CGRP-LI. After trigeminal rhizotomy, almost all CGRP-LI axons disappeared from the ipsilateral sensory trigeminal nuclei, while a considerable number of SP-LI axons remained intact throughout the nuclei; these SP-LI axons did not show CGRP-LI. The results indicate that CGRP-LI axons within the sensory trigeminal nuclei exhibit SP-LI and are of peripheral origin, and that SP-LI axons without CGRP-LI are of central origin.

Immunohistochemical demonstration of coexistence of enkephalin- and substance P-like immunoreactivities in axonal components in the lumbar segments of cat spinal cord

Coexistence of enkephalin-like and substance P-like immunoreactivities (ENK-LI and SP-LI) was shown in axonal components in the lumbar segments of cat spinal cord by using the double immunofluorescence method. Although axonal components labeled with both ENK-LI and SP-LI were distributed throughout the spinal gray, they were most dense in the ventral horn, and most sparse in the superficial part of the dorsal horn.

Convergence of serotonin-, enkephalin- and substance P-like immunoreactive afferent fibers onto cat medullary dorsal horn projection neurons: a triple immunocytochemical staining technique combined with the retrograde HRP-tracing method

Convergence of serotonin (5-HT)-, enkephalin (ENK)-, and substance P (SP)-like immunoreactive (LI) afferent fibers onto cat medullary dorsal horn projection neurons was examined by retrogradely labeling trigeminothalamic neurons and immunocytochemically labeling 5-HT, ENK and SP fibers in the same tissue section using distinct chromogens. Convergence of 5-HT-, ENK- and SP-LI fibers upon single projection neurons was often observed in laminae I and V.

Enkephalin-, substance P- and serotonin-like immunoreactive axonal varicosities in close apposition to perikarya of mesencephalic trigeminal nucleus neurons in the cat

A light microscopic study in adult cats provided evidence suggesting that neuronal cell bodies of mesencephalic trigeminal nucleus neurons were often in direct contact with axonal varicosities showing enkephalin-, substance P- or serotonin-like immunoreactivity.

Possible origins of substance P-like immunoreactive axons within Onuf's nucleus of the cat

The double immunofluorescence method revealed that 30-50% of substance P-like immunoreactive (SP-LI) axons within Onufs nucleus of cats exhibited enkephalin (ENK)-LI, and that about 5% of SP-LI axons within the nucleus showed serotonin (5-HT)-LI. After hemicordotomy, axons with both SP- and 5-HT-LI, as well as those with only 5-HT-LI, were profoundly depleted in Onufs nucleus ipsilateral to the lesion, but no changes were detectable in axons with SP-LI and/or ENK-LI in the nucleus.

Retinofugal projections in the house musk shrew, Suncus murinus

Retinofugal projections in the house musk shrew (Suncus murinus) were studied with the WGA-HRP method. After WGA-HRP injection into the vitreous cavity of one eye, terminal labeling was seen in the suprachiasmatic nucleus, dorsal and ventral lateral geniculate nuclei, pretectum and superficial layer of the superior colliculus. The terminal labeling in the suprachiasmatic nucleus was more marked on the side ipsilateral to the injection than on the contralateral side, whereas that in other regions was seen mainly on the contralateral side. A retino-intergeniculate leaflet projection was observed. No unequivocal terminal labeling was found in the lateroposterior thalamic nucleus.