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H Nawa

Publications and source records attributed to H Nawa.

At least 73 records · Page 4Linked to original sources
PubMed1994

Intraventricular administration of BDNF increases neuropeptide expression in newborn rat brain.

Brain-derived neurotrophic factor (BDNF) specifically enhances and maintains the expression of neuropeptide Y (NPY) and somatostatin (SOM) in cultured neocortical neurons (Nawa et al., 1993). In this article, we examined its effects in vivo on neuropeptide expression in various brain regions by injecting BDNF into the cerebroventricle of newborn rats. Repeated administration (2x) of BDNF increased contents of NPY-like immunoreactivity (NPY-LI) and substance P (SP)-LI most markedly in the anterior neocortex by 11- and 24-fold, respectively, in comparison to values in the animals receiving control injection. A smaller but significant increase was also observed in immunoreactivity for somatostatin (SOM), enkephalin (ENK), and cholecystokinin (CCK). mRNA for NPY, SP, and SOM was similarly upregulated in the anterior neocortex, suggesting that BDNF enhances peptide synthesis rather than inhibiting peptide release or degradation. Among the brain regions examined, however, peptidergic responses to BDNF were different with respect to their spatial distribution and time course. Induction of SP-LI, NPY-LI, and SOM-LI around the injection site was most pronounced in cortical layers II/III, layers IV-VI, and layer VI, respectively. Peptidergic immunoreactivity was also enhanced in other brain regions ipsilateral to the injection site, for example, NPY-LI in the hippocampus, thalamic nuclei, and striatum, and SOM-LI in the striatum. A single injection of BDNF elevated SP-LI to a plateau level within 12 hr while NPY-LI and SOM-LI reached maximum levels at 48 hr, and then all returned to control levels at 68 hr. In contrast, the same dose of NGF had no influences on the neuropeptide levels at 48 hr. These observations suggest that BDNF regulates the development of neuropeptide expression in the CNS in a plastic manner.

Animals↗
PubMed1994

Regulation of protein kinase CK2 isoform expression during rat brain development.

Protein kinase CK2 is very abundant in rat brain when compared with other rat tissues. The enzyme is an oligomeric protein with the structures alpha 2 beta 2, alpha alpha'beta 2 and alpha'2 beta 2. The alpha and alpha' subunits are catalytic and have a high degree of homology, whereas the beta subunit seems regulatory. Using specific antibodies to synthetic peptide antigens that discriminate among the alpha, alpha', and beta subunits of CK2, we have observed a significant increase in the amount of alpha' subunit during the late postnatal neocortical maturation period. The increased alpha' expression occurs at a parallel time to synaptogenesis. As for its distribution, the alpha' subunit of CK2 is much more abundant in neurons (particularly in large size neurons) than it is in glia. These results are consistent with a hypothetical role for CK2 isoforms containing alpha' subunits in the regulation of specific functions in fully differentiated neurons.

Amino Acid Sequence↗
PubMed1993

Molecular characterization of a novel retinal metabotropic glutamate receptor mGluR6 with a high agonist selectivity for L-2-amino-4-phosphonobutyrate.

A cDNA clone for a new metabotropic glutamate receptor, termed mGluR6, was isolated from a rat retinal cDNA library by cross-hybridization with the previously isolated cDNA clone for a metabotropic glutamate receptor. The cloned mGluR6 subtype consists of 871 amino acid residues and exhibits a structural architecture common to the metabotropic receptor family, possessing a large extracellular domain preceding the seven putative membrane-spanning domains. mGluR6 shows the highest sequence similarity to mGluR4 among the metabotropic receptor subtypes and inhibits the forskolin-stimulated cyclic AMP accumulation in Chinese hamster ovary cells transfected with the cloned cDNA. mGluR6 potently reacts with L-2-amino-4-phosphonobutyrate (L-AP4) and L-serine-O-phosphate, and the potencies of these compounds are one order of magnitude greater than that of L-glutamate. Blot and in situ hybridization analyses indicated that mGluR6 mRNA is restrictedly expressed in the inner nuclear layer of the retina where ON-bipolar cells are distributed. The metabotropic receptor that responds strongly to L-AP4 and L-serine-O-phosphate in ON-bipolar cells is known to mediate glutamate synaptic transmission between photoreceptor cells and ON-bipolar cells. On the basis of the agonist selectivity of mGluR6 and its specific expression in retinal cells, the physiological role of this receptor subtype in the visual system is discussed.

Amino Acid Sequence↗
PubMed1993

Partial cloning of the rat choline acetyltransferase gene and in situ localization of its transcripts in the cell body of cholinergic neurons in the brain stem and spinal cord.

We have isolated recombinant lambda (lambda) phages which contain a part of the rat choline acetyltransferase (ChAT) gene. Restriction and Southern blot analyses using synthetic oligonucleotides indicate that these clones overlap one another and contain at least four exons which reside in 16.4 kb of sequence encoding from the middle to the 3' end, but not the 5'-region, of the rat ChAT gene. Partial sequence analyses revealed that the clones contain an exon whose nucleotide sequence corresponds to a highly conserved region of ChAT during evolution. RNase protection mapping experiments show that sequences represented by this exon are expressed at high levels in the spinal cord of adult rats and at low but detectable levels in PC12 cells. By using the genomic sequences, including the exon, as a hybridization probe, we have detected ChAT mRNAs in situ in rat tissues. In situ hybridization experiments using radioactive and non-radioactive probes revealed that cholinergic motoneurons in the spinal cord, the laterodorsal tegmental nucleus as well as the hypoglossal nucleus in the brain stem were labeled, suggesting that the genomic sequence can be used as a probe to measure the ChAT mRNA levels in those cholinergic neurons. The results also indicate that the non-radioactive method gives a better resolution in localizing the expression of ChAT transcripts in the cytoplasm of cholinergic neurons.

Amino Acid Sequence↗
PubMed1993

Glutamate receptor agonists enhance the expression of BDNF mRNA in cultured cerebellar granule cells.

The influence of glutamate and its analogues on the expression of BDNF mRNA was studied in cultured cerebellar granule cells. Four-hour exposure of the neurons to the glutamate receptor agonists, quisqualate, kainate, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) and N-methyl-D-aspartate (NMDA), increased levels of BDNF mRNA. Glutamate in combination with antagonists of the ionotropic glutamate receptors, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), D-2-amino-5-phosphonovalerate (AP-5) and/or (+)-5-methyl-10,11-dihydro-5H-dibenzocyclohepten-5,10-imine hydrogen maleate (MK-801), also increased levels of BDNF mRNA. However, the addition of glutamate itself to the cultures produced severe neuronal death and failed to increase the mRNA level. The onset of the increase in BDNF mRNA by kainate and NMDA lagged behind that by quisqualate. These results indicate that the non-ionotropic glutamate receptor might be involved in the induction of BDNF mRNA. Quisqualate is known to be a potent agonist of both the AMPA/kainate receptor and the metabotropic glutamate receptor. The specific antagonists of the AMPA/kainate receptor, CNQX and 6,7-dinitroquinoxaline-2,3-dione (DNQX) failed to block the increase of BDNF mRNA by quisqualate. Moreover, the desensitization of the metabotropic glutamate receptor by phorbol ester abolished the increase of BDNF mRNA by quisqualate. These results suggest that stimulation of the metabotropic glutamate receptor may be the most predominant component to increase BDNF mRNA in cerebellar granule cell culture.

2-Amino-5-phosphonovalerate↗
PubMed1993

Regulation of neuropeptide expression in cultured cerebral cortical neurons by brain-derived neurotrophic factor.

The neuropeptide-inducing activity of neurotrophic factors was tested in cultured cerebral cortical neurons. Brain-derived neurotrophic factor (BDNF) specifically increased contents of the neuropeptides somatostatin (SOM) and neuropeptide Y (NPY), but its effect on contents of cholecystokinin octapeptide and GABA was much less significant. The maximal induction of NPY content (15-fold increase) was achieved by 20 ng/ml of BDNF. These changes were also reproduced at the mRNA level. In contrast, neurotrophin-3 was much less potent at increasing NPY and SOM contents, and nerve growth factor had no effect on them. The expression of mRNA for NPY and SOM was fully dependent on the presence of BDNF in culture but irrelevant to the survival-promoting activity of BDNF, which has been reported previously. Most of the NPY immunoreactivity induced by BDNF was colocalized with glutamate decarboxylase immunoreactivity in cultured cortical neurons. These results suggest that BDNF regulates the peptidergic expression of GABAergic neurons in the cerebral cortex.

Animals↗
PubMed1993

Glutamate and quisqualate regulate expression of metabotropic glutamate receptor mRNA in cultured cerebellar granule cells.

Metabotropic glutamate receptor (type 1; mGluR1) is expressed predominantly in the hippocampus and the cerebellum. Using cultured cerebellar granule cells, we investigated the regulation of the mGluR1 mRNA expression. Levels of mGluR1 mRNA were decreased to less than half by high potassium stimulation and by glutamate and quisqualate. Although these glutamate receptor agonists tested are also known to cause neuronal cell death in culture, the effect of cell death cannot explain the observed reduction in mGluR1 mRNA because of the following reasons: (a) antagonists of N-methyl-D-aspartate and non-N-methyl-D-aspartate receptors inhibited cell death, but not the reduction of the level of mGluR1 mRNA; (b) mGluR1 mRNA returned to its initial level 48 h after the agonist application; and (c) the mRNA level of one of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate/kainate receptors (GluR1) was not altered by these conditions. Therefore, we conclude that the glutamate or quisqualate stimulation can specifically inhibit the expression of mGluR1 mRNA. The dose response of quisqualate for the reduction in mGluR1 mRNA is consistent with that for inositol phosphate formation stimulated through the cloned mGluR1. The mRNA reduction did not require extracellular calcium. Desensitization of mGluR1 with phorbol ester abolished the mRNA reduction. These results suggest that the reduction in mGluR1 mRNA is mediated by the activation of the metabotropic receptor itself.

Animals↗
PubMed1992

Molecular characterization of a novel metabotropic glutamate receptor mGluR5 coupled to inositol phosphate/Ca2+ signal transduction.

A cDNA clone for a new metabotropic glutamate receptor, mGluR5, was isolated through polymerase chain reaction-mediated DNA amplification by using primer sequences conserved among the metabotropic glutamate receptor (mGluR) family and by the subsequent screening of a rat brain cDNA library. The cloned receptor consists of 1171 amino acid residues and exhibits a structural architecture common to the mGluR family, possessing a large extracellular domain preceding the seven putative membrane-spanning segments. mGluR5 shows the highest sequence similarity to mGluR1 among the mGluR members and is coupled to the stimulation of phosphatidylinositol hydrolysis/Ca2+ signal transduction in Chinese hamster ovary cells transfected with the cloned cDNA. This receptor also resembles mGluR1 in its agonist selectivity and antagonist responses; the potency rank order of agonists for mGluR5 was determined to be quisqualate greater than L-glutamate greater than or equal to ibotenate greater than trans-1-aminocyclopentane-1,3-dicarboxylate. Blot and in situ hybridization analyses indicated that mGluR5 mRNA is widely distributed in neuronal cells of the central nervous system and is expressed differently from mGluR1 mRNA in many brain regions. This investigation thus demonstrates that there is an additional mGluR subtype which closely resembles mGluR1 in its signal transduction and pharmacological properties and is expressed in specialized neuronal cells in the central nervous system.

Amino Acid Sequence↗
PubMed1992

Cooperative regulation of calcitonin gene-related peptide levels in rat sensory neurons via their central and peripheral processes.

Calcitonin gene-related peptide (CGRP) is present in both motor and sensory neurons and transported in the somatofugal direction. CGRP levels in sensory neurons are assumed to be regulated by NGF supplied from their peripheral targets. In cultured sensory neurons, however, a basal level of CGRP persists even without NGF. This suggests that some additional factors may be involved in regulation of CGRP levels of sensory neurons. The present study shows that chronic section of the sciatic nerve in the rat reduces CGRP levels in the lumbar dorsal root ganglia (DRG), whereas section of dorsal roots increases CGRP levels in the DRG. This increased CGRP level by dorsal rhizotomy was associated with enhancement of the CGRP mRNA expression in the DRG. Thus, CGRP expression in DRG appears to be regulated reciprocally via their central and peripheral processes. When the sciatic nerve had been cut 1 week previously, however, dorsal rhizotomy no longer increased CGRP levels in the lumbar DRG. Therefore, stimulation of CGRP synthesis in the DRG by dorsal rhizotomy may require the integrity of the peripheral processes. When NGF had been infused into the central stump of the cut sciatic nerve, dorsal rhizotomy again increased CGRP levels in the DRG, despite prior section of the peripheral processes. We conclude that CGRP expression in sensory neurons may be regulated by cooperative action of some factors derived via their central processes and NGF supplied from the peripheral targets.

Animals↗
PubMed1991

Recombinant cholinergic differentiation factor (leukemia inhibitory factor) regulates sympathetic neuron phenotype by alterations in the size and amounts of neuropeptide mRNAs.

The cholinergic differentiation factor (CDF) in heart cells is identical to leukemia inhibitory factor (LIF). Recombinant CDF/LIF was shown to alter dramatically neurotransmitter production as well as the levels of several neuropeptides in cultured rat sympathetic neurons. Here it is shown that these changes are likely to be caused by alterations in the mRNA for these proteins and peptides. Growth in 1 nM recombinant CDF/LIF induces mRNA for acetyl CoA: choline-O-acetyltransferase [EC 2.3.1.6; choline acetyltransferase (ChAT)], somatostatin (SOM), substance P, and vasoactive intestinal polypeptide while lowering mRNA levels of tyrosine hydroxylase (EC 1.14.16.2) and neuropeptide Y (NPY). In addition, the sizes of the mRNAs for ChAT, SOM, and NPY are larger after recombinant CDF/LIF treatment.

Animals↗
PubMed1990

Separation and partial characterization of neuropeptide-inducing factors in heart cell conditioned medium.

Various conditioned media contain multiple factors that regulate the expression of the neurotransmitters acetylcholine, serotonin, and catecholamines and the neuropeptides substance P, somatostatin, vasoactive intestinal polypeptide-related peptides, cholecystokinin, and enkephalins in cultured sympathetic neurons. Using biochemical and immunological methods, we identify at least three distinct factors in heart cell conditioned medium: one induces acetylcholine, substance P, somatostatin, and vasoactive intestinal polypeptide-related peptides while suppressing catecholamine expression, a second factor induces only vasoactive intestinal polypeptide-related peptides, and a third factor induces only somatostatin expression. These observations demonstrate the existence of a group of biochemically and immunologically distinct factors involved in phenotypic specification with unique, but partially overlapping activities. The analogy with the family of differentiation factors in the hematopoietic system is discussed.

Animals↗
PubMed1990

Different biological activities in conditioned media control the expression of a variety of neuropeptides in cultured sympathetic neurons.

An intriguing question regarding neuronal development is how neurons choose which neurotransmitter and/or peptide to express among over 40 candidates. We find that heart cell conditioned medium (CM) induces a number of neuropeptides and/or their precursor mRNAs, as well as acetylcholine, in cultured rat sympathetic neurons: substance P, somatostatin, vasoactive intestinal polypeptide, enkephalin derivatives, and cholecystokinin, but not neuropeptide Y. Different patterns of peptide induction were observed for CMs from primary cultures of heart, gut, and skin. Acetylcholine and substance P were induced most effectively by serum-free heart cell CM; enkephalin derivatives were induced most effectively by skin cell CM; and somatostatin and vasoactive intestinal polypeptide were induced equally well by all of the CMs. These observations suggest the possibility that many distinct, diffusible factors can influence the choice of transmitter and/or peptide phenotype in developing neurons.

Animals↗
PubMed1990

[Morphological characteristics of the cranio-facial structure of Chinese (Taiwanese) young adults].

In this study 26 males (average age: 16 y 9 m) and 23 females (average age: 16 y 7 m) were selected from Chungtai Medical Junior College in Taichung, Taiwan. Head films of these students were traced and analysed. Mean values of the Chinese young adults in Taiwan were calculated and the conclusions were as follows: 1) Linear measurements of this present study were compared to Lin's in both males and females. A significant difference was noticed in the skeletal pattern. 2) Angular measurements of this present study were compared to Lin's data of stage IIIC. The gonial angle of this present study was smaller than Lin's data. However, no significant differences were noticed in the positional relationship of upper and lower jaws. 3) Regarding the axes of the anterior teeth, a lingual tipping tendency of the upper anterior teeth and a labial tipping tendency of the lower anterior teeth were observed. 4) The linear measurements in the present study were compared to the Japanese data of stage V. The anterio-posterior dimension of the chinese maxilla was larger than the Japanese. However, there are no significant differences in the position of the upper and lower jaws in females. 5) The measurements of the mandible in this study were smaller than those of the Japanese data. The gonial and mandibular plane angles, especially, were significantly smaller than those of Japanese. 6) The axes of upper and lower anterior teeth of Taiwanese showed more labial tipping than those of Japanese in this study.

Adolescent↗
PubMed1988

Nucleotide sequences of cDNAs for human papillomavirus type 18 transcripts in HeLa cells.

HeLa cells expressed 3.4- and 1.6-kilobase (kb) transcripts of the integrated human papillomavirus (HPV) type 18 genome. Two types of cDNA clones representing each size of HPV type 18 transcript were isolated. Sequence analysis of these two types of cDNA clones revealed that the 3.4-kb transcript contained E6, E7, the 5' portion of E1, and human sequence and that the 1.6-kb transcript contained spliced and frameshifted E6 (E6*), E7, and human sequence. There was a common human sequence containing a poly(A) addition signal in the 3' end portions of both transcripts, indicating that they were transcribed from the HPV genome at the same integration site with different splicing. Furthermore, the 1.6-kb transcript contained both of the two viral TATA boxes upstream of E6, strongly indicating that a cellular promoter was used for its transcription.

Amino Acid Sequence↗
PubMed1986

Sequence analysis of cloned cDNA for rat substance P precursor: existence of a third substance P precursor.

The sequence of the mRNA for the rat substance P precursor (preprotachykinin A) has been elucidated by molecular cloning and sequence analysis. The deduced amino acid sequence of rat preprotachykinin A indicates that it contains both substance P and substance K but differs in the sequence organization from either bovine alpha- or beta-preprotachykinin A reported previously. The existence of the bovine mRNA for the third preprotachykinin A has thus been examined and evidenced by the isolation of the corresponding cDNA clone. This mRNA, named gamma-preprotachykinin A mRNA, deletes the sequence precisely corresponding to the exon 4 sequence of the preprotachykinin A gene. Thus, alternative RNA splicing in the expression of the single preprotachykinin A gene results in the generation of three different forms of the preprotachykinin A mRNAs.

Amino Acid Sequence↗