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Biomedical subjects

M Tohyama

Publications and source records attributed to M Tohyama.

At least 523 records · Page 29Linked to original sources
PubMed1983

Distribution and origins of neurotensin-containing fibers in the nucleus ventromedialis hypothalami of the rat: an experimental immunohistochemical study.

The distribution and origins of neurotensin (NT)-containing fibers in the nucleus ventromedialis hypothalami (VM) of the rat were investigated experimentally using an indirect immunofluorescence technique. A dense plexus of NT-like immunoreactive (NTI) fibers which was composed of very fine varicosities was identified in the VM. Although they were distributed throughout its entire rostrocaudal extent, the distribution was uneven. The highest density was identified in the dorsomedial part of the VM. In the central part, a less numerous but still moderate number of NTI fibers was detected in its dorsal part. But in a ventrolateral direction, they decreased in number and in the ventrolateral part only a few NTI fibers were seen. The present study demonstrated experimentally that these fibers originate from the medial nucleus of the amygdaloid complex (AM), since destruction of the AM resulted in a marked reduction of NTI fibers ipsilaterally in the VM. These findings suggest that the AM influences the VM's functions via neurotensin-like immunoreactive fibers.

Amygdala↗
PubMed1983

Ontogeny of cholecystokinin-8-containing neuron system of the rat: an immunohistochemical analysis. I. Forebrain and upper brainstem.

Ontogeny of the cholecystokinin-8 (CCK) neuron system in the forebrain and upper brainstem of the rat was investigated by means of indirect immunofluorescence. CCK cells and fibers first appeared in the developing ventral tegmental area and in the primordium of the medial forebrain bundle, respectively, at gestational day 15 (12-14-mm embryos). From that time, CCK cells appeared in various areas of the forebrain and upper brainstem until birth and reached the maximum content at postnatal day 10. After postnatal day 10, although CCK cells tended to decrease slightly in number, colchicine treatment in the adult rats brought out numerous CCK cells in the same areas. In contrast, although CCK fibers developed only slightly during the fetal period, marked development was seen after birth, particularly between postnatal days 5 and 10. After that time, as the rats grew, CCK fibers continued to increase in number and formed a meshwork of varying density in various areas of the forebrain and upper brainstem.

Animals↗
PubMed1983

Vasoactive intestinal polypeptide (VIP)-containing neurons in the spinal cord of the rat and their projections.

The distribution of vasoactive intestinal polypeptide (VIP)-like immunoreactive structures in the rat spinal cord and their projections were investigated by means of an immunofluorescent method. In the normal rat, a small number of VIP-positive fibers were observed in the superficial layer of the dorsal horn and in the lateral funiculus. With colchicine pretreatment, VIP-positive neurons were demonstrated in the lateral spinal nucleus (lsn) and in the lamina X (Rexed). Transections of the spinal cord at various levels revealed that some of the VIP neurons in the lsn might project to supraspinal areas via lateral funiculus.

Animals↗
PubMed1983

Overall distribution of substance P-containing nerves in the wall of the cerebral arteries of the guinea pig and its origins.

The overall distribution of substance P-like immunoreactivity (SPI) in the wall of the cerebral arteries and their origins were investigated in the guinea pig by using whole-mounts. Two types of SPI fibers were seen: one forming dense fiber bands and located among the periadventitial nerves, and the other forming a meshwork. The SPI fibers located in the periadventitial nerves often leave these nerves to form a meshwork of SPI fibers of varying density according to the diameter or location of the blood vessels. The present study suggests that: (1) SPI fibers located on the circle of Willis and its branches originate from SPI cells in the trigeminal ganglion; (2) SPI fibers of the rostral one-third of the basilar artery originate partly from trigeminal SPI cells; and (3) SPI fibers in the caudal two-thirds of the basilar artery originate exclusively from other SPI cells, apart from the trigeminal ganglion.

Animals↗
PubMed1983

Evidence for the existence of a substance P-containing pathway from the nucleus laterodorsalis tegmenti (Castaldi) to the medial frontal cortex of the rat.

A long ascending substance P (SP)-containing pathway from the nucleus laterodorsalis tegmenti (TLD) to the medial frontal cortex (MFC) has been demonstrated by means of experimental immunohistochemical procedures. The unilateral destruction of the TLD, which contains numerous SP-like immunoreactive (SPLI) cells, resulted in a marked ipsilateral decrease in the SPLI fibers in the MFC.

Afferent Pathways↗
PubMed1983

Experimental immunohistochemical studies on the distribution and origins of substance P in the medial preoptic area of the rat.

Distribution of substance P (SP)-positive fibers in the medial preoptic area (POM) of the rat and their origins were examined using indirect immunofluorescence. A very high density of SP-positive fibers was seen in the POM throughout its entire rostro-caudal extent. However, the distribution of these fibers was not even; the highest density was detected in the medial part of the POM, with less dense but still numerous fibers in the lateral part. On the other hand, in this area a small number of SP-positive cells could be found; a few cells were scattered in the rostral part and, in the caudal part, several cells could be seen in the ventral part of the POM. The origins of SP-positive fibers in the POM were experimentally examined. Since the destruction of the ventro-lateral part of the anterior hypothalamus (vlAH), where numerous SP-positive cells were seen, resulted in a marked decrease of SP-positive fibers in the POM on the operated side, the majority of these fibers may originate from SP-positive cells in the vlAH. The fine structure of SP-positive terminals in the POM were investigated by electron-microscopic immunohistochemical techniques. Immunoreactive terminals contained a few large granular vesicles together with numerous small vesicles, and they made synaptic contacts mainly with dendrites which were devoid of immunoreactive materials. Two different synaptic contacts could be distinguished: one asymmetrical (Gray's type I) and the other symmetrical (Gray's type II), with the latter being predominant.

Animals↗
PubMed1983

Experimental and immunohistochemical studies concerning the major origins of the substance P-containing fibers in the lateral lemniscus and lateral parabrachial area of the rat, including the fiber pathways.

The origins and pathways of substance P-containing fibers in the lateral lemniscus and lateral parabrachial area of the rat were investigated by means of the indirect immunofluorescence technique. Following the placement of various knife cuts or lesions, the following could be concluded: (1) The cells of origin of substance P-containing fibers in the lateral lemniscus and lateral parabrachial area are localized in the ventral reticular formation of the rhombencephalon from the level of P2.8 to P7.0 in the atlas of Palkovits and Jacobowitz; (2) The fibers from these origins pass the ventral reticular formation of the rhombencephalon to form a dense bundle; (3) the fibers turn dorsally at the mid-rhombencephalon junction to reach the lateral lemniscus and lateral parabrachial area. The present study demonstrates the linking of the functions of the parabrachial area and lateral lemniscus via substance P innervation.

Animals↗
PubMed1983

Overall distribution of vasoactive intestinal polypeptide-containing nerves on the wall of cerebral arteries: an immunohistochemical study using whole-mounts.

The overall distribution of vasoactive intestinal polypeptide (VIP)-like immunoreactivity on the wall of the cerebral arteries, including its 3-dimensional profile, was investigated by means of the indirect immunofluorescence method using flat-mounts. VIP-immunoreactive fibers run spirally on the wall of the cerebral arteries. On the wall of the large arteries, such as the vertebral artery, basilar artery, internal carotid artery, within and/or without the circle of Willis, posterior and anterior communicating arteries, proximal parts of anterior, mid and posterior cerebral arteries, these fibers are richly distributed and show a dense grid-like appearance. The highest density was identified on the wall of the anterior cerebral artery, internal carotid artery and anterior communicating artery, while the lowest density was on the posterior communicating artery. On the other hand, on the walls of the branches of these arteries or along distal parts of the anterior, mid and posterior cerebral arteries, the number of VIP-immunoreactive fibers decreased markedly.

Animals↗
PubMed1983

Ontogeny of cholecystokinin-8 containing neuron system of the rat: an immunohistochemical analysis--II. Lower brain stem.

The ontogeny of the cholecystokinin-8 neuron system in the lower brain stem of the rat was investigated by means of indirect immunofluorescence. Cholecystokinin-8-like immunoreactive structures first appeared in the primordium of the ventral tegmental area, ventral tegmental nucleus of Gudden and the area lateral to the superior central nucleus of the fetus on gestational day 17. Although cholecystokinin-8-like immunoreactive structures appeared gradually in various lower brain stem areas from this day, and developed markedly from postnatal day 6, thereafter, the ontogeny of cells and fibers was different. In general, the fibers increased in number as the rats grew and reached the maximum in adulthood, whereas the cells reached a maximum number between postnatal days 6-12, after which they decreased in number. Colchicine treatment, however, demonstrated the presence of cholecystokinin-8-like immunoreactive cells in various areas of the lower brain stem. These findings suggest that the cholecystokinin-containing neuron system is active in the adult and that cholecystokinin-containing cell somata cannot store a sufficient amount of the peptide for visualization in the absence of colchicine. Thus, it might be concluded that cholecystokinin may play an important role in the brain function of the adult as a neurotransmitter or neuromodulator, though its exact function is now open to discussion.

Animals↗
PubMed1983

The distribution of cholecystokinin octapeptide-like structures in the lower brain stem of the rat: an immunohistochemical analysis.

The distribution of immunoreactive cholecystokininoctapeptide (CCK-8)-like structures in the lower brain stem of the rat was investigated using indirect immunofluorescence. In addition to the well known immunoreactive CCK-8-like containing cell groups such as those in the ventral tegmental area, substantia grisea centralis of the mesencephalon, and n. linealis rostralis, the present study demonstrated a much wider distribution of immunoreactive CCK-8-like cells in the lower brain stem, i.e. those in the inferior colliculus, n. parabrachialis colliculi posterioris, lateral lemniscus, lateral parabrachial area, n. centralis superior, nucleus of group O, pontine substantia grisea centralis, n. tractus solitarii, area postrema, n. tractus spinalis nervi trigemini and reticular formation just dorsal to the inferior olivary complex. We also demonstrated an extensive network of immunoreactive CCK-8-like fibers in various areas of the lower brain stem, including the auditory system, visual system, viscerosensory area, parabrachial nucleus, dorsal and ventral tegmental nuclei, and interpeduncular nucleus. The possible importance of CCK is briefly discussed.

Animals↗
PubMed1983

Ontogeny of neurotensin-containing neuron system of the rat: immunohistochemical analysis--II. Lower brain stem.

The ontogeny of the neurotensin neuron system in the lower brain stem of the rat was investigated by means of indirect immunofluorescent method. Neurotensin-like immunoreactivity-containing cells first appear in the primordium of the n. tractus solitarii, n. tractus spinalis nervi trigemini, reticular formation just medial to the latter nucleus, n. reticularis parvocellularis, n. laterodorsalis tegmenti, and midbrain reticular formation of the fetus at gestational day 17. At gestional day 18, neurotensin-immunoreactive cells newly appear in the n. raphe dorsalis. Between gestational day 19 and postnatal day 7, the animals show a remarkable increase in number of immunoreactive cells and fibers in various lower brain stem areas except for n. tractus spinalis nervi trigemini and n. tractus solitarii. Moreover, during this stage, neurotensin-immunoreactive cells located in the n. prepositus hypoglossi and n. vestibularis lateralis appear for the first time at birth and postnatal day 5, respectively. Since postnatal day 7, although the majority of immunoreactive cells located in the lower brain stem decrease in number as the rats grow, immunoreactive cells in the n. tractus spinalis nervi trigemini, on the contrary, increase in number from after birth until postnatal day 10, and maintain more or less their immunoreactivity even in the adult rat. In addition, neurotensin-immunoreactive cells in the nucleus of the solitary tract increase in number during the fetal period, reach the maximum content at postnatal day 7-10, and maintain their immunoreactivity even in the adult rats. Thus, the present study demonstrated that neurotensin-like immunoreactive structures appear at a very early ontogenetical stage, suggesting that neurotensin plays an important role in the development of the lower brain stem of the rat. In addition, the present study further showed that neurotensin-immuno-reactivity shows various fluctuations during the ontogeny, suggesting multiple functions of neurotensin in the central nervous system.

Animals↗
PubMed1983

Evidence for the existence of a neurotensin-containing pathway from the endopiriform nucleus and the adjacent prepiriform cortex to the anterior olfactory nucleus and nucleus of diagonal band (Broca) of the rat.

The origin of neurotensin-like immunoreactive fibers to the anterior olfactory nucleus and nucleus of the diagonal band of Broca of the rat were elucidated experimentally using the indirect immunofluorescence method. Neurotensin-like immunoreactive fibers located in these areas decreased remarkably in numbers on the operated side after the destruction of the ventral part of the endopiriform nucleus and the adjacent prepiriform cortex where numerous cells with neurotensin-like immunoreactivity were detected. This strongly suggests that such cells located in the endopiriform nucleus and the adjacent prepiriform cortex send a neurotensin-like projection ipsilaterally to the anterior olfactory nucleus and to the nucleus of the diagonal band of Broca.

Animals↗
PubMed1983

Reticulo-facial enkephalinergic pathway in the rat: an experimental immunohistochemical study.

Enkephalins have been detected in the cranial motor nuclei and may play a role in the motor system. The afferent source of leucine-enkephalin-like immunoreactive fibers in the facial nucleus was investigated using experimental immunohistochemistry. These leucine-enkephalin-containing fibers were markedly reduced on the operated side after the destruction of the ventrolateral part of the caudal medullary reticular formation, where a number of leucine-enkephalin-positive cell bodies were observed. This fact strongly suggests that these leucine-enkephalin-positive cells project ipsilaterally to the facial nucleus and so could have some effects on facial motoneurons.

Animals↗
PubMed1983

Precise terminal fields of the descending somatostatinergic neuron system from the amygdaloid complex of the rat.

The descending somatostatin (SOM) tract from the amygdaloid complex to the lower brain stem and upper cervical cord in the rat was investigated experimentally by means of the indirect immunofluorescence technique. The present study demonstrates that SOM neurons in the amygdaloid complex send their axons ipsilaterally to various lower brain stem areas and to the upper cervical cord, because destruction of the amygdaloid complex resulted in various degrees of ipsilateral reduction of SOM fibers: a marked decrease in n. reticularis pontis oralis et caudalis, n. reticularis parvocellularis, n. reticularis gigantocellularis, n. reticularis medulae oblongatae pars dorsalis et ventralis and hypoglossal nucleus; a less marked decrease in the midbrain reticular formation, central gray matter of the mesencephalon, facial nucleus and lamina VII of REXED of the upper cervical cord from C1 to C2; and a small decrease in n. reticularis paramedianus and n. reticularis lateralis. These findings were supported by other experiments performed in this study.

Amygdala↗
PubMed1983

Leucine-enkephalin-like immunoreactivity in the chicken retina with a special reference to its fine structures.

Leucine-enkephalin-like immunoreactivity (LEI) in the chicken retina was investigated using light and electron microscopic immunohistochemistry. A flat-mount technique for light microscopy clearly demonstrated that LEI cells were distributed widely throughout the entire retina, without any differences between the central and peripheral retinal regions. Frozen sections for light microscopy confirmed the previous findings in pigeons that LEI is localized in amacrine cells. The present electron microscopic observations confirmed the findings of light microscopy and revealed that LEI terminals make synaptic contract mainly with vesicle-containing processes that seemed to belong to the amacrine cells. The present study further suggests that LEI terminals are both pre- and postsynaptic elements onto vesicle-containing processes mentioned above.

Animals↗