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T Kayahara

Publications and source records attributed to T Kayahara.

At least 37 records · Page 2Linked to original sources
PubMed1994

Descending projections from the superior colliculus to the reticular formation around the motor trigeminal nucleus and the parvicellular reticular formation of the medulla oblongata in the rat.

We observed by the anterograde and retrograde tracing techniques in the rat that the lateral part of the superior colliculus (SC), where the nigrotectal fibers from the dorsolateral part of the substantia nigra pars reticulata (SNr) terminated, sent projection fibers to the reticular region around the motor trigeminal nucleus (RFmt) and parvicellular reticular formation (RFp) of the medulla oblongata, where many premotor neurons for the orofacial motor nuclei were known to be distributed. The SC neurons sending their axons to the RFmt and RFp were mainly located in the stratum griseum intermedium, and additionally in the stratum griseum profundum. Our results suggest that neuronal signals conveyed through the nigro-tecto-bulbar pathway to the RFmt and RFp may exert control influences upon oral behavior.

Animals↗
PubMed1994

Delta 22-beta-muricholic acid in monoassociated rats and conventional rats.

Bile acids were analyzed in the bile, small and large intestines, and feces of germ-free rats after a single inoculation with one of six intestinal bacteria that had been originally isolated from human feces. Bacteroides vulgatus and Bifidobacterium longum preferentially deconjugated tauro-beta-muricholic acid and taurocholic acid, respectively. Clostridium ramosum, Peptostreptococcus productus and Lactobacillus gasseri deconjugated both bile acids, but Escherichia coli did not deconjugate either one. Rats inoculated with bacteria that deconjugated tauro-beta-muricholic acid produced delta 22-beta-muricholic acid in the feces. In contrast, delta 22-cholic acid could not be detected in rats inoculated with bacteria that deconjugated taurocholic acid.

Animals↗
PubMed1994

Degeneration of locus coeruleus axons in stress-induced depression model.

Antidepressants such as desipramine induce axonal regeneration of brain noradrenergic neurons. This novel action of antidepressants suggests the involvement of degeneration or retraction of brain noradrenergic axons in the pathophysiology of clinical depression. The present study was designed to further confirm this view in an animal model of stress-induced depression. The depression model was produced by exposing rats to prolonged forced walking stress. To see if axonal degeneration of noradrenergic neurons occurred in the depression model, the density of noradrenergic axons in the cerebral cortex was assessed by three different methods, antidromic stimulation technique, retrograde tracing with horseradish peroxidase and immunohistochemical staining with dopamine-beta-hydroxylase antiserum. These methods all assured of degenerative changes of noradrenergic axon terminals in the depression model. Furthermore, it was found that repeated treatments of the depression-model rats with imipramine could cause regeneration of cortical noradrenergic axons. These findings support the view that degeneration or retraction of noradrenergic axons is involved in the pathophysiology of depression.

Animals↗
PubMed1994

Enhancement of serine-sensitivity by a gene encoding rhodanese-like protein in Escherichia coli.

When cells of Escherichia coli are grown on lactate (or other carbon sources), an addition of serine to the medium causes growth inhibition. This growth inhibition is caused by inhibition by serine of homoserine dehydrogenase I, which is involved in threonine-isoleucine biosynthesis [Hama, H., Sumita, Y., Kakutani, Y., Tsuda, M., & Tsuchiya, T. (1990) Biochem. Biophys. Res. Commun. 168, 1211-1216]. We have cloned and sequenced genes which enhance the serine-sensitivity. Two open reading frames were found and designated as sseA and sseB. Introduction of either sseA or sseB gene, or both, into E. coli cells enhanced the serine-sensitivity. The sseA gene elicited stronger enhancement than sseB. The deduced amino acid sequence of SseA showed considerable similarity with that of bovine liver rhodanese, which catalyzes sulfur transfer from thiosulfate. We observed a twofold increase in rhodanese activity in E. coli cells harboring a plasmid carrying the sseA gene. The position of sseA in the genetic map is around 52'. However, sseA is different from cysM, which codes for O-acetylserine sulfhydrylase-B, an enzyme catalyzing sulfur transfer from thiosulfate to O-acetylserine, the map position of which is also around 52'.

Amino Acid Sequence↗
PubMed1994

Properties of the Na+/H+ antiporter in Vibrio parahaemolyticus.

The properties of the Na+/H+ antiporter in Vibrio parahaemolyticus, a slightly halophilic bacterium, were investigated using everted membrane vesicles. It appears that at least two Na+/H+ antiporters are present, one that is pH-dependent and one that is pH-independent. These two antiporters appear to correspond to the NhaA and NhaB antiporters of Escherichia coli, respectively. It seems that amiloride strongly inhibits the pH-dependent antiporter. Na+ is the best substrate for both of the two V. parahaemolyticus antiporters. Li+ is a poorer substrate and K+ is not a substrate. No K+/H+ antiport activity was detected in membrane vesicles of this organism. The Na+(Li+)/H+ antiport activity greatly increased with an increase in pH of the assay medium. pH did not affect the Km value of the Na+/H+ antiport, but it did increase the Vmax.

Hydrogen-Ion Concentration↗
PubMed1994

Lithium toxicity and Na+(Li+)/H+ antiporter in Escherichia coli.

The lithium ion (Li+) shows toxicity against Escherichia coli cells when present in a high concentration in the environment. Since Li+ is extruded from cells via a Na+(Li+)/H+ antiporter, this antiporter must be involved in the detoxification of Li+. Two Na+(Li+)/H+ antiporters (NhaA system and NhaB system) are known to be present in E. coli. We investigated the properties of the antiporters and the participation of these systems in the detoxification of Li+ using mutants lacking one of the antiporters, or lacking both of them. Although the affinity for Li+ of the two systems was almost the same, the Vmax value for Li+ transport of the NhaA system was about 12 times larger than that of the NhaB system. Wild type cells were unable to grow in the presence of 0.7 M LiCl. Although a wild type cell and a mutant lacking the NhaB system grew in the presence of 0.6 M LiCl, a mutant lacking the NhaA system did not. This second mutant grew in the presence of 0.1 to 0.2 M LiCl. A mutant lacking both the NhaA and NhaB systems could not grow in the presence of 30 mM LiCl.

Escherichia coli↗
PubMed1993

Cortical connections of the motor thalamic nuclei in the Japanese monkey, Macaca fuscata.

Our findings revealed the nucleus ventralis lateralis pars oralis (VLo) projection to motor area, and the nucleus ventralis anterior pars principalis (VApc) projections to the premotor and supplementary motor areas (SMA). The VLo gave rise to thalamocortical projections terminating in the superficial half of layer I, mainly in the forelimb motor area. The VApc gave rise to the superficial projections to the post-arcuate premotor area around the arcuate genu and arcuate spur as well as SMA. We suggested that the medial pallidal segment projects to the motor area via VLo, and to the premotor area and SMA via VApc. We also proposed that the premotor area and SMA receive cerebellar afferents via nucleus ventralis lateralis pars caudalis and area X.

Animals↗
PubMed1992

Single retinal ganglion cells sending axon collaterals to the bilateral superior colliculi: a fluorescent retrograde double-labeling study in the Japanese monkey (Macaca fuscata).

Single retinal ganglion cells projecting bilaterally to the superior colliculi (SC) by way of axon collaterals were revealed in the Japanese monkey (Macaca fuscata). After injecting Fast blue into the SC on one side and Diamidino yellow into the SC on the opposite side, some retinal ganglion cells were double-labeled with both tracers. Most of them were large cells (more than 25 microns in diameter), and were localized in a narrow strip around the vertical meridian of the retina on each side. This retinal area roughly corresponds to the reported strip of nasotemporal overlap, where both crossed and uncrossed retinofugal projections arise.

Amidines↗
PubMed1992

Non-dopaminergic neurons in the substantia nigra project to the reticular formation around the trigeminal motor nucleus in the rat.

The dorsolateral part of the substantia nigra (SN) of the rat was observed to send projection fibers to the reticular formation (RF) around the trigeminal motor nucleus (Vm), bilaterally with a clear-cut ipsilateral dominance, by the anterograde and retrograde tracing techniques with PHA-L and WGA-HRP. A combination of retrograde tracing and immunohistochemistry for tyrosine hydroxylase (TH) revealed that no SN neurons sending their axons to the RF around the Vm showed TH-like immunoreactivity.

Animals↗
PubMed1992

An autoradiographic study of cortical projections from motor thalamic nuclei in the macaque monkey.

The special areal and laminar distributions of cortical afferent connections from various thalamic nuclei in the monkey (Macaca fuscata) were studied by using the anterograde axonal transport technique of autoradiography. The following findings were obtained. The superficial thalamocortical (T-C) projections, terminating in the (superficial half of) cortical layer I, arise mainly from the nucleus ventralis anterior, pars principalis (VApc) and nucleus ventralis lateralis, pars oralis (VLo), and possibly from the nucleus ventralis lateralis, pars medialis (VLm) and nucleus ventralis anterior, pars magnocellularis (VAmc). The VApc gives rise to the superficial T-C and deep T-C projections onto the postarcuate premotor area around the arcuate genu and spur, and onto the dorsomedial part of the caudal premotor area as well as the supplementary motor area (SMA). The VApc also gives rise to only deep T-C projections onto the remaining premotor area and onto the rostral bank of the arcuate sulcus as well as the ventral bank of the cingulate sulcus at the level of the premotor area. The VLo gives rise to the superficial T-C projections onto the ventrolateral part of the motor area (mainly to the forelimb motor area) and onto the dorsomedial part to the mesial cortex at the rostral level of the motor area. The VAmc gives rise to the superficial T-C projections onto the banks of the arcuate genu and adjacent region of area 8. Area X, the nucleus ventralis posterolateralis, pars oralis (VPLo), nucleus ventralis posterolateralis, pars caudalis (VPLc), nucleus ventralis posteromedialis (VPM) and possibly the nucleus ventralis lateralis, pars caudalis (VLc) send only deep T-C projections. The dorsal and medial parts of the VLc project onto the premotor area, the rostral part of the motor area and the SMA, and also the ventral bank of the cingulate sulcus. Area X projects onto the premotor area, the SMA, and the caudal part of area 8. The thalamic relay nuclei projecting onto the frontal association cortex were found to be the VAmc, medial VLc and area X.

Afferent Pathways↗
PubMed1992

Properties of recombinant cells capable of growing on serine without NhaB Na+/H+ antiporter in Escherichia coli.

Escherichia coli HIT-1 has a mutation in the Na+/H+ antiporter gene, nhaB (P. Thelen, T. Tsuchiya, and E. B. Goldberg, J. Bacteriol. 173:6553-6557, 1991). This strain is not able to utilize serine as a carbon source (T. Ishikawa, H. Hama, M. Tsuda, and T. Tsuchiya, J. Biol. Chem. 262:7443-7446, 1987), because an active NhaB is required to maintain the electrochemical potential of Na+, which drives serine transport via the Na+/serine carrier, the major transport system for serine. We isolated recombinant cells from a cross between strains HIT-1 and Hfr, and these cells were able to grow on serine even though the NhaB Na+/H+ antiporter of the recombinant cells was still defective. We found that the activity of the H+/serine cotransport system, one of the minor serine transport systems in E. coli, was elevated in the recombinant cells. H+/serine cotransport activity was induced by leucine in the recombinant cells more strongly than in strain HIT-1. A kinetic analysis showed that the Vmax, but not the Km, of the transport system was much higher in the recombinant cells than in strain HIT-1 cells.

Biological Transport↗
PubMed1991

Non-dopaminergic projections from the substantia nigra pars lateralis to the inferior colliculus in the rat.

The substantia nigra pars lateralis (SNI) of the rat was found, by the anterograde and retrograde tracing methods, to send projection fibers to the peripheral shell region surrounding the central nucleus of the inferior colliculus (IC), bilaterally with a clear-cut ipsilateral dominance. SNI neurons sending their axons to the IC were distributed throughout the entire rostrocaudal extent of the SNI. None of these SNI neurons showed tyrosine hydroxylase-like immunoreactivity.

Animals↗
PubMed1991

Inhibition of homoserine dehydrogenase I by L-serine in Escherichia coli.

We have reported that a major cause of growth inhibition of Escherichia coli by L-serine is its inhibition of homoserine dehydrogenase I (HDH I), which is involved in the biosyntheses of threonine and isoleucine [Hama, H., Sumita, Y., Kakutani, Y., Tsuda, M., & Tsuchiya, T. (1990) Biochem. Biophys. Res. Commun. 168, 1211-1216]. However, Patte et al. reported that L-serine does not inhibit HDH I [Patte, J.-C., Truffa-Bachi, P., & Cohen, G.N. (1966) Biochim. Biophys. Acta 128, 426-439]. In studies on the reason for these discrepant results, we found that the concentration of K+ and the pH in the assay mixture strongly influenced the inhibitory effect of L-serine. L-Serine strongly inhibited the HDH I activities in both the forward and reverse reactions between aspartate semialdehyde and homoserine at a physiological K+ concentration (100 to 200 mM) and physiological pH (7.5) for E. coli cells. On the other hand, two well-known inhibitors of HDH I, L-threonine and L-cysteine, strongly inhibited the activity regardless of the K+ concentration and pH.

Cations, Monovalent↗
PubMed1990

Topographical projections from the thalamus, subthalamic nucleus and pedunculopontine tegmental nucleus to the striatum in the Japanese monkey, Macaca fuscata.

Topographical projections from the thalamus, subthalamic nucleus (STN) and pedunculopontine tegmental nucleus (PPN) to the striatum were examined in the Japanese monkey (Macaca fuscata) by using the retrograde axonal transport technique of WGA-HRP (wheat germ agglutinin-conjugated horseradish peroxidase). After WGA-HRP injection in the head of the caudate nucleus (CN) or putamen (Put), labeled neuronal cell bodies in the thalamus were distributed mainly in the nucleus ventralis anterior (VA)-nucleus ventralis lateralis (VL) complex and the nucleus centrum medianum (CM)-nucleus parafascicularis (Pf) complex, and additionally in the paraventricular, parataenial, rhomboid, reuniens, centrodorsal, centrolateral, paracentral, and centromedial nuclei. The data indicated that the pars principalis of VA (VApc) projected mainly to CN and additionally to Put, and that the pars magnocellularis of VA (VAmc) or pars oralis of VL (VLo) projected selectively to CN or Put, respectively. It was also indicated that CM projected to the middle and caudal parts of Put, while Pf projected to CN and the rostral part of the Put. The data further indicated that the dorsomedial, ventromedial, or lateral part of CM projected respectively to the dorsolateral, ventromedial, or intermediate part of Put, and that the medial or lateral part of Pf projected respectively to the medial or lateral part of the head of CN. Direct projections from STN and PPN to the striatum were confirmed. The subthalamostriatal projections showed a mediolateral topography. The PPN was shown to project bilaterally to the striatum with an ipsilateral predominance.

Animals↗
PubMed1990

The subparafascicular thalamic nucleus of the rat receives projection fibers from the inferior colliculus and auditory cortex.

The sources of afferent fibers to the subparafascicular thalamic nucleus (SPF) of the rat were investigated by the retrograde WGA-HRP and anterograde PHA-L methods. Layer V of the areas 3, 1 and 2 of the temporal cortex as well as the dorsal and external cortices of the inferior colliculus were found to send projection fibers to the whole rostrocaudal extent of the SPF bilaterally with a clear-cut ipsilateral dominance. The results indicate that the SPF of the rat may constitute a relay nucleus in the central auditory pathways.

Animals↗
PubMed1990

Direct projections from the globus pallidus to the inferior colliculus in the rat.

A retrograde and anterograde wheat germ agglutinin-horseradish peroxidase (WGA-HRP) study in the rat indicated that some neurons in the globus pallidus (GP) sent their axons ipsilaterally to the inferior colliculus (IC). These neuronal cell bodies were located in the ventrolateral portions of the caudal part of the GP, and their axons were distributed mainly in the peripheral region of the external cortex of the IC.

Animals↗
PubMed1986

Synaptic connections between spinal motoneurons and dorsal root ganglion cells in the cat.

Light- and electron-microscopical horseradish peroxidase (HRP) studies have been employed in conjunction with a degeneration study in order to clarify the origin and axonal passage of afferent synaptic terminals in cat dorsal root ganglia. After injection of HRP into ganglia (C3) without involvement of the ventral roots and spinal nerves, a few ipsilateral spinal ventral horn neurons (C3) were retrogradely labeled with HRP. The labeled neurons were localized in the dorsomedial and the ventromedial nuclei. Following ventral rhizotomy of C3, the afferent terminals in the ganglia (C3) anterogradely degenerated and contained accumulated and disintegrated neurofilaments, depleted, aggregated and enlarged synaptic vesicles. Subsequent to an HRP and wheat germ agglutinin (WGA)-HRP-mixture injection into the dorsal neck or suboccipital muscles, many spinal motoneurons (C3) were labeled retrogradely with an HRP mixture. On the other hand, the afferent synaptic terminals in ganglia contained the membrane-bound and electron-dense bodies which were anterogradely labeled with an HRP mixture in addition to the normal synaptic elements. The present findings strongly suggest that some spinal motoneurons send their axon collaterals to the dorsal root ganglia, in which the terminals of the axon collaterals directly synapse with the dorsal root ganglion cells.

Animals↗