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K Hagihara

Publications and source records attributed to K Hagihara.

34 records · Page 2Linked to original sources
PubMed1993

Detection and levels of androgen receptor messenger ribonucleic acid in the rat brain by means of reverse transcription-polymerase chain reaction.

In order to examine the existence and level of androgen receptor messenger ribonucleic acid (ARmRNA) in the rat brain, reverse transcription-polymerase chain reaction (RT-PCR)-Southern blot analysis was carried out. Total RNA extracted from each tissue was reverse transcribed, followed by PCR with two oligonucleotide primers specific for a part (458 bp) of the androgen binding domain of the rat ARcDNA. It was confirmed by direct nucleotide sequencing that the amplified fragment corresponded to part of the rat ARcDNA. To detect and quantify the amplified fragments, a Southern blot analysis was carried out. The levels of amplified fragments were calculated from the standard curve obtained from graded diluted adrenal total RNAs. In the present study, it was revealed that the RT-PCR-Southern blot analysis possessed a high-degree of sensitivity and allowed the quantitative estimation of mRNA. With this method, amplified fragments were obtained from all five brain regions examined. The results indicate that ARmRNA is widely distributed in the whole brain. Moreover, since the ARmRNA level roughly paralleled the AR protein level, it seems that the AR protein level in the brain may be primarily regulated by the ARmRNA level.

Amino Acid Sequence↗
PubMed1992

Distribution of cells containing progesterone receptor mRNA in the female rat di- and telencephalon: an in situ hybridization study.

In an attempt to examine regional synthesis of the progesterone receptor (PR) in the brain, the distribution of mRNA encoding PR was investigated in the female adult rat di- and telencephalon by in situ hybridization using T7 RNA polymerase transcripts of a 320 base pair rat PR cDNA clone. The rat PR cDNA had been partially cloned and sequenced by using the reverse transcription-polymerase chain reaction (RT-PCR) method. The primer set corresponds to a part of the progesterone binding domain of human PR cDNA. Large numbers of strong labeling were observed in the arcuate nucleus, medial preoptic nucleus, and ventrolateral part of the ventromedial nucleus which are relative to sexual behavior. Moderate labeling was found in layers II and IV of the isocortex, in the pyramidal layer of the CA1 and CA3 fields of the hippocampal formation, in the cortical nucleus of the amygdala, in the nucleus of the diagonal band, and in the anterior periventricular nucleus. Weak labeling was found in many other regions. These results were largely in agreement with the distribution of PR previously reported by ligand binding assay and autoradiographic studies. This present in situ hybridization study may provide a useful tool for the analysis of the regional regulation of PR synthesis in the rat brain.

Animals↗
PubMed1992

Expression of estrogen receptor in the rat brain: detection of its mRNA using reverse transcription-polymerase chain reaction.

Reverse transcription-polymerase chain reaction (RT-PCR)-Southern blotting was employed for biochemical detection and measurement of the estrogen receptor messenger ribonucleic acid (ERmRNA) in various parts of the Wistar strain female rat brain. Total RNA extracted from the tissues was subjected to RT-PCR using the primer set which flanked the part(287bp) of the estrogen binding domain-corresponding region of the rat ERcDNA. It was confirmed that the RT-PCR product corresponded to the part of the ERcDNA by direct nucleotide sequencing of the product. Moreover, the level of ERmRNA could be determined by Southern blotting which was highly sensitive and produced quantitative results. The RT-PCR product of about 290 bp, corresponding in length to the distance between two primers, was generated from RNA of all the tissues examined. The levels of the product were as follows; anterior hypophysis greater than hypothalamus and preoptic area, amygdala much greater than cerebral cortex, cerebellum. These results indicate that ERmRNA is widely distributed in the whole brain, implying some physiological action of estrogen on target and 'non-target' brain regions.

Animals↗
PubMed1992

Expression of progesterone receptor in the neonatal rat brain cortex: detection of its mRNA using reverse transcription-polymerase chain reaction.

Our previous reports have revealed the postnatal developmental pattern of progesterone receptor (PR) in the rat cerebral cortex, but little is known about PRmRNA changes in the tissue so far. In the present study, we have attempted to detect and quantify PRmRNA in the tissue by the use of the reverse transcription-polymerase chain reaction (RT-PCR)-dot blot analysis. Cerebral cortical tissues were dissected from female Wistar rats at 2 and 8 days of age. Total RNA extracted from the tissues was reverse transcribed, followed by PCR. The PCR primer set, whose sequence was derived from the human clone, flanked the part (320 bp) of the human PRcDNA which corresponded to the progesterone binding domain. The 320 bp of the RT-PCR product was generated from rat uterine RNA. The amino acid sequence deduced from the nucleotide sequence of the product had a 95.5% identity with the corresponding region in human PR, confirming that the product had originated from the rat PRmRNA. Moreover, a highly sensitive and quantitative assay for rat PRmRNA had been developed by the use of RT-PCR-dot blotting. The PRmRNA was detectable in the cerebral cortex of both 2- and 8-day-old rats by the assay. Furthermore, the level of cortical PRmRNA of the 8-day-old rats were greater than the 2-day-old rats. These results indicate that the RT-PCR assay is useful for detection and quantification of PRmRNA in the neonatal rat cerebral cortex, and that increment of the cortical PRmRNA in the 8-day-old rat is associated with a drastic change of the level of the cortical PR around day 10.

Aging↗
PubMed1990

Presence of sex difference of cytochrome P-450 in the rat preoptic area and hypothalamus with reference to coexistence with oxytocin.

Localization of female type cytochrome P-450 (F1) in the preoptic area and hypothalamus of the rat was examined immunocytochemically using antiserum against purified hepatic P-450 (F1). This antiserum recognizes both P-450 (F1) and P-450 (M3). Western immunoblotting using the antiserum demonstrated that female rat brain contains P-450 (F1) but not P-450 (M3), since microsomes from the brain and liver displayed only one immunoreactive band at 50 kD, coinciding with that of P-450 (F1) purified from female rat liver. On the other hand, the male brain has P-450 (M3) but not P-450 (F1), as liver- and brain-derived microsomes produced single band at 49 kD, which represents a mol. wt. identical to that of P-450 (M3) extracted from male rat liver. These results indicate that P-450 (F1)-like immunoreactivity (LI) occurs in the female rat brain, while P-450 (M3)-LI takes place in the male rat brain. Immunocytochemical analysis further demonstrated the detailed cellular localization of these two P-450-LIs in the preoptic area and hypothalamus of female and male rats. Localization of P-450 (F1)-LI in the female rat hypothalamus resembled that of P-450 (M3)-LI in the male rat hypothalamus. Magnocellular neurosecretory neurons in the paraventricular nucleus and supraoptic nucleus were labeled and were found to contain oxytocin but lack vasopressin when serial sections of these areas were analyzed. In addition, groups of immunoreactive cells were seen in the median preoptic nucleus, medial and lateral preoptic area, caudal portion of the bed nucleus of the stria terminalis, lateral hypothalamus at the level of the paraventricular nucleus, periventricular zone from the preoptic area to the paraventricular nucleus, and parvocellular portion of the paraventricular nucleus.

Animals↗
PubMed1989

[A case of right aortic arch associated with subclavian steal syndrome].

A 20-year-old female of right aortic arch associated with subclavian steal syndrome is reported. She was admitted to our hospital for numbness of the left arm, headache and dysphagia. Division of the ligamentum arteriosum and left common carotid-left subclavian artery anastomosis were successfully performed.

Adult↗
PubMed1988

Inhibition contributes to orientation selectivity in visual cortex of cat.

Neurons in the visual cortex are selectively responsive to light or dark bars presented at particular orientations. On the basis of physiological data, this orientation selectivity is hypothesized as being due at least partially to intracortical inhibitory mechanisms. But this hypothesis has been challenged by intracellular recordings indicating that excitatory inputs themselves are orientation-selective, so inhibition may not contribute to the observed selectivity. Also, there is controversy about the presence of intracortical horizontal connections mediating inhibition for selectivity and about the theoretical validity of such inhibitory connections. Using cross-correlation analysis of the activities of two neurons recorded simultaneously, we find that inhibitory interactions exist between cells with somewhat different, but not orthogonal, orientation preferences. This suggests that intracortical horizontal inhibition operates between 'orientation columns' to sharpen the orientation tuning of cortical neurons.

Action Potentials↗
PubMed1988

Actions of excitatory amino acid antagonists on geniculo-cortical transmission in the cat's visual cortex.

To test the possibility that glutamate and aspartate are transmitters at geniculo-cortical synapses and to elucidate which type of receptors for the excitatory amino acids (EAA) operate at these synapses, we studied effects of microiontophoretic administration of EAA antagonists on the responses of visual cortical neurons to afferent electrical and visual stimulation in the cat. The antagonists used were kynurenate, a non-selective antagonist for all classes of EAA receptors and 2-amino-5-phosphonovalerate (APV), a selective antagonist for N-methyl-D-aspartate (NMDA)-preferring receptors. The administration of kynurenate suppressed responses elicited by electrical stimulation of the dorsal lateral geniculate nucleus (LGN) and optic chiasm (OX) of 65% of the cells tested. This suppression was more marked for the short-latency responses which were evoked monosynaptically from the LGN, than for the longer-latency responses. In contrast with the effectiveness of kynurenate, APV failed to suppress electrically and visually elicited responses in 66% of the cortical cells. Such differences between kynurenate and APV were particularly prominent in layers IV and VI, which receive direct inputs from the LGN, but were less marked or were not recognizable in layers II + III and V. These results support previous suggestions that EAAs may be excitatory transmitters in the cerebral cortex, at least at geniculo-cortical synapses, and indicate further that EAA receptors of the "non-NMDA type" may be involved in afferent synaptic transmission in the cat's visual cortex.

2-Amino-5-phosphonovalerate↗
PubMed1987

Effects of cholinergic depletion on neuron activities in the cat visual cortex.

1. Unilateral lesions of the nucleus basalis magnocellularis (nBM), a source of cholinergic projection to the cerebral cortex, were produced by injection of kainic acid in the cat. The lesions caused a significant reduction in density of choline acetyltransferase-immunoreactive terminals in the visual cortex ipsilateral to the lesions. 2. In the primary visual cortex ipsilateral to the lesions [acetylcholine (ACh)-depleted cortex], about half of the cells had weak or undetectable visual responses, whereas in the contralateral visual cortex almost all the cells had normal responsivity. The response selectivity, such as orientation and direction selectivities, of cortical cells was not affected by the depletion of ACh. 3. The microionophoretic application of ACh to cells under observation facilitated visual responses in 83% of the cells recorded from the ACh-depleted cortex, whereas it suppressed the responses in only 9%. The application of a muscarinic antagonist, atropine, to cells in the ACh-depleted cortex was ineffective, suggesting no residual ACh activity. 4. The mean current required to induce facilitation in the cortex ipsilateral to the lesion was significantly smaller than that required in the contralateral cortex and the visual cortex of the normal cat, suggesting a supersensitivity of receptors mediating the effect or a reduction in catabolism of exogenous ACh in the ACh-depleted cortex. 5. More than half of the cells that had been unresponsive to visual stimuli became clearly responsive during the ACh application. The response magnitude of cortical cells, as a whole, increased to the same degree as that observed during the ACh application in the normal cat. 6. In addition to the decrease in the average response magnitude, there was a remarkable variability in responses of cells to motion of the slit from sweep to sweep in the ACh-depleted cortex. The application of ACh to cortical cells decreased the variability of responses and consequently made the responses much more consistent. 7. These results suggest that without ACh supplied from the nBM, most of the cortical neurons could not respond briskly and consistently to excitatory inputs and that exogenously applied ACh could reverse such an impairment of cortical neurons through intact or even supersensitive postsynaptic receptors.

Acetylcholine↗
PubMed1986

Effects of capsaicin on lipid metabolism in rats fed a high fat diet.

Effects of capsaicin, a pungent principle of hot red pepper, were studied in experiments using male rats fed a diet containing 30% lard. Capsaicin was supplemented at 0.014% of the diet. The level of serum triglyceride was lower when capsaicin was present in the diet than when it was not. Levels of serum cholesterol and pre-beta-lipoprotein were not affected by the supplementation of capsaicin. The perirenal adipose tissue weight was lower when capsaicin was present in the diet than when it was not. Hepatic enzyme activities of glucose-6-phosphate dehydrogenase and adipose lipoprotein lipase were lower in rats fed the 30% lard diet than in those fed a nonpurified diet. Activities of these two enzymes were higher when capsaicin was added to the diet than when it was not. Hepatic acetyl-CoA carboxylase, beta-hydroxyacyl-CoA dehydrogenase, and adipose hormone-sensitive lipase activities were not affected by capsaicin feeding. Lipid absorption was not affected by the supplementation of capsaicin. The perirenal adipose tissue weight and serum triglyceride were decreased as the level of capsaicin in the diet increased up to 0.021%. These results suggest that capsaicin stimulates lipid mobilization from adipose tissue and lowers the perirenal adipose tissue weight and serum triglyceride concentration in lard-fed rats.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMedDate not supplied

NMDA receptors in the visual cortex of young kittens are more effective than those of adult cats.

Acidic amino acids, such as glutamate and aspartate, are thought to be excitatory transmitters in the cerebral neocortex and hippocampus. Receptors for these amino acids can be classified into at least three types on the basis of their agonists. Quisqualate-preferring receptors and kainate-preferring receptors are implicated in the mediation of synaptic transmission in many regions including the hippocampus and visual cortex, whereas N-methyl-D-aspartate (NMDA)-preferring receptors are thought to be involved in modulating synaptic efficacy, for example in longterm potentiation, a form of synaptic plasticity in the hippocampus. In the visual cortex of the cat and monkey, it is well established that synaptic plasticity, estimated by susceptibility of binocular responsiveness of cortical neurons to monocular visual deprivation, disappears after the 'critical' period of postnatal development. Here we report that during the critical period in young kittens, a selective NMDA-receptor antagonist blocks visual responses of cortical neurons much more effectively than it does in the adult cat. This suggests that NMDA receptors may be involved in establishing synaptic plasticity in the kitten visual cortex.

Aging↗
PubMedDate not supplied

Antifungal compounds induced in the dual culture with Phytolacca americana callus and Botrytis fabae.

In order to investigate new metabolites which are only induced in a plant callus infected by a pathogenic fungus, dual cultures with combinations of 10 species of fungi and 6 plant cell lines from different species were established. Among the combinations tested, the methanolic extract of a dual culture consisting of a plant cell line, Phytolacca americana and a fungus, Botrytis fabae showed a marked antifungal activity to Cladosporium herbarum. The main active constituent of this extract was identified to be phytolaccoside B (Pls B) by the spectroscopic analyses.

Antifungal Agents↗