The effect of haloperidol on the histaminergic neuron system in the rat brain

In this study, the effect of haloperidol on histamine (HA) levels, histidine decarboxylase (HDC) activities and the bindings of [3H]-(R)-alpha-methylhistamine ([3H]-(R)-alpha-MeHA) to histamine H3 receptors were investigated in the rat brain. Administration of 10 mg/kg of haloperidol decreased HA levels in the rat striatum and diencephalon, but increased HDC activities in rat striatum and diencephalon, although that of 5 mg/kg did not change them. Meanwhile, haloperidol inhibited the bindings of [3H]-(R)-alpha-MeHA to H3 receptor sites in the rat striatal membrane with a Ki value of 10.5 +/- 0.45 microM. These findings suggest that only a high dose of haloperidol increases HA synthesis and release as a histamine H3 receptor antagonist in the rat brain.

Generalization of D-, L- and DL-chlorpheniramine and zolantidine to the discriminative stimulus effects of cocaine and methamphetamine

We recently demonstrated that some H-antagonists have cocaine or methamphetamine-like discriminative stimulus effects. In the present study, the effects of optical isomers of chlorpheniramine (D-, L- and DL-forms) on the discriminative stimulus effects of cocaine and methamphetamine were examined in rats trained to discriminate between cocaine (10.0 mg/kg) or methamphetamine (1.0 mg/kg) and saline, to determine whether these effects of H1-antagonists are mediated by the blockade of H-receptors. In generalization tests with optical isomers of chlorpheniramine, the D-, L- and DL-forms all completely generalized to the discriminative stimulus effects of cocaine, but did not generalize to those of methamphetamine. Dose-generalization by the optical isomers of chlorpheniramine to the discriminative stimulus effects of cocaine did not correlate with the H-antagonistic potency of these drugs. These results suggest that all of the optical isomers of chlorpheniramine have cocaine-like discriminative stimulus effects, but that these effects are not mediated by H1-receptor blockade. On the other hand, the H2-antagonist, zolantidine, generalized to the discriminative stimulus effects of methamphetamine, but not to those of cocaine, suggesting that zolantidine may have methamphetamine-like discriminative stimulus effects. In the present study, GBR12909 (dopamine uptake inhibitor) completely generalized to the discriminative stimulus effects of cocaine, but not to those of methamphetamine, whereas apomorphine (dopamine receptor agonist) generalized more potently to the discriminative stimulus effects of methamphetamine than to those of cocaine. These findings imply that although the dopaminergic system plays an important role in the discriminative stimulus effects of both cocaine and methamphetamine, there may be differences between their effects.

A case of the calcium pyrophosphate dihydrate (CPPD) deposition disease without condylar destruction of the temporomandibular joint

The case of calcium pyrophosphate dihydrate (CPPD) deposition disease, which occurred at a rare site in the temporomandibular joint (TMJ), is presented. A 48-year-old woman noted swelling in the preauricular area of her left cheek, which restricted her mouth opening. Radiological examination revealed a radiopaque lesion in the posterior and medial area of the left space of the TMJ. During the operation, the superior joint space was entirely filled with a solid and whitish-gray mass of chalky appearance. The lesion was partly attached to the retrodiscal tissue without any destructive change around the condyle and mandibular fossa. Histological examination revealed the foci of amorphous crystalline material to contain rhomboidal, rod and needle shaped crystals, which had cartilaginous tissue in the dense fibrous background admixed with chronic inflammatory cells and foreign body-type giant cells. The crystals were positive for von Kossa's stain and spectral peaks for phosphorus and calcium were evident by electron probe microanalysis, thus suggesting the presence of CPPD.

Therapeutic doses of theophylline exert proconvulsant effects in developing mice

We studied the effect of therapeutic doses of theophylline on electrically-induced convulsions in developing mice. A theophylline dose as small as 3 mg/kg increased seizure susceptibility of 21-day-old mice, but not of 42-day-old mice. These findings were consistent with clinical reports that theophylline at the therapeutic blood concentrations occasionally induced convulsions in children. The age-dependent proconvulsant effect of theophylline was well inhibited by phenobarbital (PB), dose-dependently, but not by other well-established antiepileptic drugs (AEDs). PB may be a good choice of AED in patients with bronchial asthma and seizure disorders, if PB is indicative for their seizure types. The proconvulsant effect of theophylline in 21-day-old mice was counteracted by not only an adenosine A1 agonist, but also an NMDA antagonist and a histamine H3 antagonist. Several studies have established that the proconvulsant effect of theophylline intoxication is mainly due to the blockade of adenosine A1 receptors. The present findings suggested that the proconvulsant properties of therapeutic doses of theophylline in developing period were different from those of theophylline intoxication. Combination of therapeutic doses of theophylline and centrally-acting histamine H1 antagonists showed proconvulsant effects even in 42-day-old mice, suggesting that peripherally acting histamine H1 antagonists, such as astemizole, evastine and epinastine, were much safer than centrally acting histamine H1 antagonists for patients with both allergy and seizure history.

Enzymatic activity and expression of cytochrome P450 LA omega within intrasplenically transplanted fetal hepatocytes in spontaneously hypertensive rats

We examined the expression and enzymatic activity of cytochrome P450 LA omega within transplanted hepatocytes. Fetal hepatocytes were harvested at day 20 of gestation from spontaneously hypertensive rats (SHRs) and transplanted into recipient adult SHR spleens. Microscopic examination of the recipient spleens at 4 and 10 wk after transplantation revealed masses of hepatocytes with cord-like structures in the red pulp. Immunochemical studies detected cytochrome (cyto) P450 LA omega in the fetal hepatocytes before transplantation without prior induction. Although the cyto P450 LA omega was not detected by the second week after transplantation, by the 6th and 10th wk after transplantation, it was. Cyto P450-arachidonic acid omega/omega-1 hydroxylase activity (formation of 20- and 19-hydroxyeicosatetraenoic acid) was detected at 10 wk after transplantation, but not 2 or 6 wk after transplantation. These results demonstrated that fetal hepatocytes can be transplanted successfully into recipient spleens and then grow in the spleens, as in the case of the adult hepatocyte response.

Enzymatic Activity and Expression of Cytochrome P450 LAω within Intrasplenically Transplanted Fetal Hepatocytes in Spontaneously Hypertensive Rats

We examined the expression and enzymatic activity of the cytochrome P450 LAω within transplanted hepatocytes. Fetal hepatocytes were harvested at day 20 of gestation from spontaneously hypertensive rats (SHRs) and transplanted into recipient adult SHR spleens. Microscopic examination of the recipient spleens 4 and 10 wk after transplantation revealed masses of hepatocytes with cordlike structures in the red pulp. Immunochemical studies detected cytochrome (cyto) P450 LAω in the fetal hepatocytes before transplantation without prior induction. Although the cyto P450 LAω was not detected by the second week after transplantation, by the 6th and 10th wk after transplantation, it was. Cyto P450-arachidonic acid ω/4oM-1 hydroxylase activity (formation of 20- and 19-hydroxyeico-satetraenoic acid) was detected at 10 wk after transplantation, but not 2 or 6 wk after transplantation. These results demonstrated that fetal hepatocytes can be transplanted successfully into recipient spleens and then grow in the spleens, as in the case of the adult hepatocyte response.

CD28-B7 T cell costimulatory blockade by CTLA4Ig in sensitized rat recipients: induction of transplantation tolerance in association with depressed cell-mediated and humoral immune responses

We tested the effects of blocking CD28-B7 T cell costimulation by using CTLA4Ig in an established transplantation model in which LBNF1 cardiac allografts are rejected in an accelerated manner (<36 h) by LEW rats presensitized with Brown-Norway skin grafts. Treatment with CTLA4Ig with or without donor alloantigen in the sensitization phase (between skin and cardiac engraftment) minimally delayed accelerated rejection. However, adjunctive infusion of CTLA4Ig and donor alloantigen in the effector phase (after cardiac engraftment) resulted in long term graft survival and donor-specific tolerance in 30 to 50% of the recipients. The mutant form of CTLA4Ig, which blocks B7-1 but not B7-2, was ineffective. The tolerant state was accompanied by reduction of cell-mediated (MLR/CTL) responses and depression of humoral (circulating IgM/IgG allo-Abs) alloreactivity in vivo. Hence, the binding of CD28 on T cells to both CD80 and CD86 ligands represents a crucial initial costimulatory step leading to accelerated graft rejection. CTLA4Ig-mediated early blockade of the CD28 signaling pathway combined with transfusion of donor cells in the perioperative period interrupts sensitization and may produce transplantation tolerance. This regimen inhibits T cell costimulation and activation to provide help to CD8+ cytotoxic T and B cells, perhaps, via CTLA4Ig-induced clonal anergy or deletion.

CD28-B7 T cell costimulatory blockade by CTLA4Ig in sensitized rat recipients: induction of transplantation tolerance in association with depressed cell-mediated and humoral immune responses

We tested the effects of blocking CD28-B7 T cell costimulation by using CTLA4Ig in an established transplantation model in which LBNF1 cardiac allografts are rejected in an accelerated manner (<36 h) by LEW rats presensitized with Brown-Norway skin grafts. Treatment with CTLA4Ig with or without donor alloantigen in the sensitization phase (between skin and cardiac engraftment) minimally delayed accelerated rejection. However, adjunctive infusion of CTLA4Ig and donor alloantigen in the effector phase (after cardiac engraftment) resulted in long term graft survival and donor-specific tolerance in 30 to 50% of the recipients. The mutant form of CTLA4Ig, which blocks B7-1 but not B7-2, was ineffective. The tolerant state was accompanied by reduction of cell-mediated (MLR/CTL) responses and depression of humoral (circulating IgM/IgG allo-Abs) alloreactivity in vivo. Hence, the binding of CD28 on T cells to both CD80 and CD86 ligands represents a crucial initial costimulatory step leading to accelerated graft rejection. CTLA4Ig-mediated early blockade of the CD28 signaling pathway combined with transfusion of donor cells in the perioperative period interrupts sensitization and may produce transplantation tolerance. This regimen inhibits T cell costimulation and activation to provide help to CD8+ cytotoxic T and B cells, perhaps, via CTLA4Ig-induced clonal anergy or deletion.

Oxidized LDLs but not native LDLs augment Ba2+ currents through L-type Ca2+ channels of the A7r5 smooth muscle-derived cell line

The whole-cell patch-clamp method was used on A7r5 smooth muscle-derived cell line, and Ba2+ currents through Ca2+ channels were recorded. The A7r5 cells showed voltage-dependent, long-lasting Ba2+ currents which were markedly inhibited by nifedipine (10 microM). The magnitude of the maximum Ba2+ current (IBa(max)) was augmented by an application of dbcAMP (1 mM), but not affected by TPA (80 nM). Noradrenaline (NA) at 100 microM caused an increase in the IBa(max) by 19.7% in the presence of phentolamine (10 microM). This effect was cancelled by Rp-cAMPs (10 microM). In the presence of propranolol (10 microM), NA tended to reduce the IBa(max). Application of Ox-LDLs at 100 microg protein/ml caused an increase in the IBa(max) by 15.7%, whereas native LDLs did not change the IBa(max). Rp-cAMPs was ineffective to the Ox-LDL action on the IBa(max). In the presence of Ox-LDLs, NA augmented the IBa(max) by 21.4% in the presence of phentolamine. These results suggest that Ox-LDLs activate L-type Ca2+ channels of A7r5 cells by a mechanism independent of cAMP/PKA signalling.

Effect of cocaine on the histaminergic neuron system in the rat brain

To examine the effect of cocaine on the brain histamine neuron system, histamine levels and histamine N-methyltransferase activity in the rat brain were measured after the administration of cocaine. Moreover, we examined the effect of L-histidine on cocaine-induced wheel-running behavior. The administration of cocaine (20 mg/kg) increased histamine levels and histamine N-methyltransferase activity in the striatum, nucleus accumbens, and amygdala 1 h later. The pretreatment with L-histidine (350 and 700 mg/kg) inhibited the cocaine (20 mg/ kg)-induced increase of wheel-running activity in a dose-dependent manner. These findings suggest that cocaine activates the brain histamine neuron system, which may play the role of inhibiting the cocaine-induced wheel-running behavior.

Functional assessment of proliferating hepatocytes stimulated by hepatic stimulatory substance in ascorbic acid biosynthetic enzyme-deficient rats

The functional ability of hepatic stimulatory substance (HSS)-stimulated proliferating hepatocytes was investigated by intrasplenic and/or intraportal transplantation in ascorbic acid (AsA) biosynthetic enzyme-deficient (ODS-od/od) rats that die of osteogenic disorders unless there is AsA supplementation. HSS was extracted from regenerating porcine livers. Hepatocytes isolated from the livers of congeneic ODS-+/+ rats that are capable of synthesizing AsA were transplanted into the spleen (Sp-HTx) and/or the portal vein (Pv-HTx) of ODS-od/od rats. The recipients were divided into eight groups as follows: HSS-untreated groups [group Ia, sham-operated, HTx(-); group IIa, Sp-HTx; group IIIa, Pv-HTx; and group IVa, Sp- and Pv-HTx], HSS-treated groups [group Ib, HSS only; group IIb, Sp-HTx + HSS; group IIIb, Pv-HTx + HSS; and group IVb, Sp- and Pv-HTx + HSS]. The recipients were given a diet and water containing AsA for 6 weeks after HTx, and AsA supplementation was then halted. The average bromodeoxyuridine (BrdU) labeling index (LI) and hepatocyte-occupied ratio in the spleen (H/S ratio) of HSS-treated rats were significantly higher than those of HSS-untreated rats. All the rats in HSS-untreated groups and group Ib died by 8 weeks after the cessation of AsA. In HSS-treated groups IIb, IIIb, and IVb, the survival rates were 60%, 50%, and 80%, respectively, at 16 weeks after HTx. The average serum AsA level of the surviving rats in groups IIb, IIIb, and IVb was significantly higher than that in HSS-untreated groups. These results indicate that HSS treatment induced rapid proliferation of transplanted hepatocytes in the spleen and the portal vein, and that these proliferating hepatocytes synthesized AsA and improved the survival rate of ODS-od/ od rats.

Interactions between H1-antagonists and opioids: a drug discrimination study

We previously demonstrated that combination of opioids, pentazocine and dihydrocodeine, with the histamine H1-receptor antagonists tripelennamine and chlorpheniramine could enhance their rewarding effects in rats. In the present study, the effects of combined treatment with opioids and H1-antagonists on discriminative stimulus effects were examined in rats trained to discriminate between cocaine (10 mg/kg) or morphine (3.0 mg/kg) and saline, since it is believed that discriminative stimulus effects of abused drugs are related to their rewarding effects. Tripelennamine and chlorpheniramine, but not pentazocine or dihydrocodeine, generalized to the discriminative stimulus effects of cocaine. Pentazocine (3.0 mg/kg) and dihydrocodeine (5.6 mg/kg) significantly potentiated the cocaine-like discriminative stimulus effects of low doses of tripelennamine and chlorpheniramine, respectively. On the other hand, pentazocine and dihydrocodeine, but not tripelennamine or chlorpheniramine, generalized to the discriminative stimulus effects of morphine. Neither 1.0 or 3.0 mg/kg tripelennamine nor chlorpheniramine affected the morphine-like discriminative stimulus effects of pentazocine and dihydrocodeine, respectively. These results suggest that the potentiation of the cocaine-like discriminative stimulus effects of H1-antagonists by opioids may be involved in the enhanced rewarding effects of combinations of opioids and H1-antagonists.

Arrest in primitive erythroid cell development caused by promoter-specific disruption of the GATA-1 gene

To elucidate the in vivo function of GATA-1 during hematopoiesis, we specifically disrupted the erythroid promoter of the GATA-1 gene in embryonic stem cells and generated germ line chimeras. Male offspring of chimeras bearing the targeted mutation were found to die by 12.5 days post coitus due to severe anemia while heterozygous females displayed characteristics ranging from severe anemia to normal erythropoiesis. When female heterozygotes were crossed with transgenic males carrying a reporter gene, which specifically marks primitive erythroid progenitors, massive accumulation of undifferentiated erythroid cells were observed in the yolk sacs of the GATA-1-mutant embryos, demonstrating that GATA-1 is required for the terminal differentiation of primitive erythroid cells in vivo.

Biological activities of novel zaragozic acids, the potent inhibitors of squalene synthase, produced by the fungus, Mollisia sp. SANK 10294

Four novel zaragozic acids, F-10863A, B, C and D, were isolated from a culture broth of the fungus Mollisia sp. SANK 10294. F-10863 compounds contain a 4,6,7-trihydroxy-2,8-dioxyobicyclo-[3.2.1]octane-3,4,5-tricarboxyl ic acid core like previously reported zaragozic acids, but the structures of the side chains are different. Recently, it was found that F-10863A is identical to zaragozic acid D3, while the other three are novel compounds. F-10863 compounds are potent inhibitors of squalene synthase like previously reported zaragozic acids, and, furthermore, they exhibit serum cholesterol-lowering activity in vivo.

Evidence for a functional kit receptor in melanoma, breast, and lung carcinoma cells

We sought to determine the functional significance of the c-kit receptor (Kit) in melanoma, breast carcinoma, and non-small cell lung cancer (NSCLC). To explore these issues, we first screened cell lines of each type for c-kit mRNA expression using a reverse-transcription polymerase chain reaction. We found that WM-39 melanoma cells, HTB-22 breast carcinoma cells, and A549 NSCLC cells all expressed c-kit mRNA. Of interest, all of these cells expressed the c-kit ligand, Steel factor (SF). We then assessed the functional significance of c-kit and SF expression by disrupting the gene's expression with antisense (AS) oligodeoxynucleotides (ODN) targeted to c-kit mRNA codons 1-6 and SF mRNA codons 2-7, respectively. Nonhybridizing sequences [sense (5) and scrambled (SCR)] were also employed as controls. WM-39, HTB-22, and A549 cells were exposed to ODN (approximately 25 microM) for 5-7 days. Downregulation of c-kit and SF mRNA, and c-kit protein was demonstrated in cells treated with AS ODN. Effects on viable cell growth were demonstrated by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) or 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4 -sulfophenyl)- 2H-tetrazolium (MTS) assay. In fact, c-kit antisense ODN inhibited the viable cell growth of A549 cells 66% and 79% compared to sense and untreated controls (P = .0003; P < .0001). Additionally, WM-39 cell growth was inhibited 48% and 21% (P < .0001, P < .03) and HTB-22 cell growth was inhibited 50% (P < .001) compared to sense and untreated controls. Viable cell growth was also significantly inhibited by SF AS ODN compared to S and SCR controls in all cell lines. These results demonstrate that WM-39, HTB-22, and A549 NSCLC cells all express the c-kit and SF protooncogenes and suggest that the encoded receptor and ligand are important for cell growth. By finding the presence, and functional importance, of both the receptor and ligand in these cells, this study suggests the existence of an autocrine loop growth mechanism worthy of further study.

[Renal lesions of rats induced by antibodies to cultured rat glomerular epithelial cells and mesangial cells]

Renal lesions of rats induced by antibodies to cultured rat glomerular epithelial cells (GEC) and mesangial cells (GMC) were studied. Antibodies to cultured rat GEC and GMC were produced by immunization of rabbits with GEC and GMC respectively. The rats injected with anti-GEC antibody showed a small amount of urinary protein, glomerular deposition of rabbit IgG and subepithelial dense deposits observed by electron microscopy. Proteinuria was suppressed in the rats in which complement was depleted with cobra venom factor. Western blot analysis demonstrated a band of 200 KD in GEC lysates reacted with anti-GEC antibody. The rats injected with anti-GMC antibody showed little urinary protein, glomerular deposition of rabbit IgG and mesangial dense deposits. Western blot analysis demonstrated two bands of 43 and 14 KD in GMC lysates reacted with anti-GMC antibody. These data showed that the injection of anti-GEC antibody or anti-GMC antibody induced similar lesions to passive Heymann nephritis and anti Thy 1.1 nephritis. This study suggested that antigenicity of structural glomerular cells is important as the antigens of glomerulonephritis.

GATA-1 transcription is controlled by distinct regulatory mechanisms during primitive and definitive erythropoiesis

Transcription factor GATA-1 is required for the terminal differentiation of both the primitive and definitive erythroid cell lineages, and yet the regulatory mechanisms of GATA-1 itself are not well understood. To clarify how the GATA-1 gene is transcriptionally controlled in vivo, presumptive regulatory regions of the gene were tested by fusion to a reporter gene and then examined in transgenic mice. We found that a transcriptional control element located between -3.9 and -2.6 kb 5' to the erythroid first exon serves as an activating element and that this sequence alone is sufficient to recapitulate the expression of GATA-1 (but uniquely in primitive erythroid cells). Addition of sequences from the GATA-1 first intron to this upstream element provides a necessary and sufficient condition for complete recapitulation of GATA-1 expression in both primitive and definitive erythroid cells. The first intron element does not possess intrinsic transcriptional activation potential when linked to the GATA-1 gene promoter but rather requires the upstream activating element for its activity. These experiments show that GATA-1 gene expression is regulated by discrete transcriptional control elements during definitive and primitive erythropoiesis: The 5' element displays properties anticipated for a primitive erythroid cell-specific activating element, and the novel element within the GATA-1 first intron specifically augments this activity in definitive erythroid cells.

The effect of methamphetamine on histamine release in the rat hypothalamus

In the present study, the effect of methamphetamine (MAP) on histamine (HA) release measured by in vivo brain microdialysis in the rat hypothalamus was investigated. Administration of MAP (3 mg/kg) significantly increase HA release from 40 to 160 min after the injection. This finding suggests that a moderate dose of MAP activates the hypothalamic HA neuron system, which may be related to effects of MAP on intrinsic biological rhythms.

Effects of histamine agents on methamphetamine-induced stereotyped behavior and behavioral sensitization in rats

In this study, effects of histamine (HA) agents on methamphetamine (METH)-induced stereotyped behavior and behavioral sensitization were examined in rats. Pretreatment with a precursor of HA, L-histidine (750mg/kg), significantly inhibited the METH (3 mg/kg)-induced stereotyped behavior, whereas pretreatment with an inhibitor of HA synthesis, alpha-fluoromethylhistidine (FMH) (100 mg/kg), an H1 antagonist pyrilamine (5 mg/kg) or an H2 antagonist zolantidine (5 mg/kg) enhanced it. The inhibitory effect of L-histidine on METH-induced stereotyped behavior was significantly blocked by coadministration of pyrilamine and zolantidine, indicating that the effect is mediated through H1 and H2 receptors. Moreover, chronic treatment with METH (3 mg/kg) significantly enhanced stereotyped behavior at the rechallenge with METH (1 mg/kg). Chronic treatment with L-histidine (750 mg/kg) plus METH inhibited the METH-induced argumentation of stereotyped behavior, while that with FMH (100 mg/kg), pyrilamine (5 mg/kg) or zolantidine (5 mg/kg) potentiated it. These findings suggest that the HA neuron system has an inhibitory role in METH-induced stereotyped behavior and behavioral sensitization.

Structure of human chromosome 21--for an understanding of genetic diseases including Down's syndrome

We do not intend to give information about the structure of human chromosome 21 in detail but to give a kind of perspective of the present status of our knowledge about human chromosome 21 in this article. Recent development of molecular biology has changed revolutionarily the status of our knowledge of the human chromosome in general. Therefore we will choose a few aspects of the development in this field and want to discuss how we are able to use such information to understand the genetic diseases including Down's syndrome.