Abnormal expression of the genes involved in cytokine networks and mitochondrial function in systemic juvenile idiopathic arthritis identified by DNA microarray analysis.

OBJECTIVES: Systemic juvenile idiopathic arthritis (sJIA) is a rheumatic disease in childhood characterised by systemic symptoms and a relatively poor prognosis. Peripheral leukocytes are thought to play a pathological role in sJIA although the exact cause of the disease is still obscure. In this study, we aimed to clarify cellular functional abnormalities in sJIA. METHODS: We analysed the gene expression profile in peripheral leukocytes from 51 patients with sJIA, 6 patients with polyarticular type JIA (polyJIA) and 8 healthy children utilising DNA microarrays. Gene ontology analysis and network analysis were performed on the genes differentially expressed in sJIA to clarify the cellular functional abnormalities. RESULT: A total of 3491 genes were differentially expressed in patients with sJIA compared to healthy individuals. They were functionally categorised mainly into a defence response group and a metabolism group according to gene ontology, suggesting the possible abnormalities in these functions. In the defence response group, molecules predominantly constituting interferon (IFN)gamma and tumour necrosis factor (TNF) network cascades were upregulated. In the metabolism group, oxidative phosphorylation-related genes were downregulated, suggesting a mitochondrial disorder. Expression of mitochondrial DNA-encoded genes including cytochrome c oxidase subunit 1(MT-CO1) and MT-CO2 were suppressed in patients with sJIA but not in patients with polyJIA or healthy children. However, nuclear DNA-encoded cytochrome c oxidases were intact. CONCLUSION: Our findings suggest that sJIA is not only an immunological disease but also a metabolic disease involving mitochondria disorder.

Transforming growth factor-beta/Smads signaling induces transcription of the cell type-restricted ankyrin repeat protein CARP gene through CAGA motif in vascular smooth muscle cells.

Transforming growth factor (TGF)-beta plays a major role in the development of vascular diseases. Despite the pleiotropic effects of TGF-ss on vascular smooth muscle cells (VSMCs), only a few genes have been characterized as direct targets of TGF-beta in VSMCs. Cardiac ankyrin repeat protein (CARP) has been thought to be expressed exclusively in the heart. In the present study, we showed that CARP is expressed in the vasculature after balloon injury and in cultured VSMCs in response to TGF-beta. Analysis of a half-life of the cytoplasmic CARP mRNA levels and the transient transfection of the CARP promoter/luciferase gene indicates that the regulation of CARP expression is increased by TGF-beta at the transcriptional level. Transfection of expression vectors encoding Smads significantly activated the CARP promoter/luciferase activity. Deletion analysis and site-specific mutagenesis of the CARP promoter indicate that TGF-beta response element is localized to CAGA motif at -108 bp relative to the transcription start site. Electrophoretic mobility shift assays showed that the binding activity to the CAGA motif was increased in nuclear extracts of cultured VSMCs by TGF-beta. Cells transfected with adenovirus vector expressing CARP showed a significant decrease in DNA synthesis. Overexpression of CARP enhanced the TGF-beta-mediated inhibition of the DNA synthesis. These data indicate that CARP is a downstream target of TGF-beta/Smad signaling in VSMCs and suggest a role of CARP in mediation of the inhibitory effects of TGF-beta on the proliferation of VSMCs.

Homeobox protein Hex induces SMemb/nonmuscle myosin heavy chain-B gene expression through the cAMP-responsive element.

Recent studies have shown that the homeobox gene Hex plays an important role in inducing differentiation of vascular endothelial cells. In this study, we examined the expression of Hex in vascular smooth muscle cells (VSMCs) in vitro and in vivo. Immunohistochemistry showed a marked induction of Hex protein in neointimal VSMCs after balloon injury in rat aorta. Western and reverse transcriptase-polymerase chain reaction analyses demonstrated that Hex was abundantly expressed in cultured VSMCs, whereas it was undetectable in other cell types or in normal aorta. The expression pattern of Hex was similar to that of SMemb/NMHC-B, a nonmuscle isoform of myosin heavy chain that we have previously reported to be a molecular marker of dedifferentiated VSMCs. We next examined the role of Hex in SMemb gene transcription. Promoter analysis demonstrated that the sequence identical to consensus cAMP-responsive element (CRE) located at -481 of the SMemb promoter was critical for Hex responsiveness. Mutant Hex expression vector, which lacks the homeodomain, failed to stimulate SMemb gene transcription, suggesting the requirement of the homeodomain for its transactivation. Elecrophoretic mobility shift assay showed that Hex binds to a consensus binding sequence for homeobox proteins, but not to CRE. Cotransfection of protein kinase A expression vector increased the ability of Hex to stimulate SMemb promoter activity in a CRE-dependent manner. Overexpression of CRE binding protein (CREB), but not Mut-CREB which contains mutation at Ser133, strongly activated Hex-induced SMemb promoter activity. These results suggest that Hex mediates transcriptional induction of the SMemb/NMHC-B gene via its homeodomain, and Hex can function as a transcriptional modulator of CRE-dependent transcription in VSMCs.

Glomerulonephritis in children with mixed connective tissue disease.

AIMS: Mixed connective tissue disease (MCTD) has overlapping clinical features with systemic lupus erythematosus (SLE). Renal biopsy is necessary for all children with SLE to evaluate the prognosis, because they are at a quite high risk of developing renal complications. Furthermore, lupus nephritis and hypocomplementemia usually precede the appearance of clinical manifestations. Immune complex-mediated nephritis is one of the major complications of MCTD. Juvenile MCTD is known to be associated with a higher risk of nephritis than adult MCTD. However, it is uncertain whether all children with MCTD should be subjected to a renal biopsy, and whether most of those with hypocomplementemia present nephropathy, as in patients with SLE. We examined the histopathological characteristics of juvenile MCTD nephritis, the importance of renal biopsy and the implications of hypocomplementemia in our patients and reported cases of MCTD. MATERIAL AND METHODS: We performed renal biopsy in 11 children with MCTD and found 6 patients with glomerulonephritis. In addition, we studied the frequency and the characteristics of glomerulonephritis in 71 cases of juvenile MCTD (our 11 patients and 60 reported cases). We also analyzed the relationship between hypocomplementemia and pathological features in 41 cases of MCTD nephritis (23 adults, 18 children). RESULTS: 6 of our 11 patients had glomerulonephritis, but of them four had no abnormality in urinalysis at the time of biopsy. In 5 patients renal biopsy showed normal findings. Review of 71 cases of juvenile MCTD showed that of them 28% presented latent asymptomatic nephritis at the time of biopsy. Membranous nephropathy (MN) and mesangial proliferative glomerulonephritis (MPG) were common in MCTD. Interestingly, hypocomplementemia was more frequently observed in patients with MN or mixed form of MN and MPG (MPG/MN) than simple MPG based on our review of 41 cases (p < 0.01). CONCLUSION: A more aggressive indication of renal biopsy should be considered in children with MCTD because of the high incidence of non-clinical nephritis. The hypocomplementemia observed in patients with MCTD suggests the high frequency of glomerulonephritis, including membranous lesions.

Molecular cloning of rabbit CARP cDNA and its regulated expression in adriamycin-cardiomyopathy.

A full-length rabbit cDNA of cardiac adriamycin responsive protein (CARP) has been cloned. It shows high levels of identity at the amino acid sequence level (>86%) with the rat, mouse and human homologues. CARP mRNA levels are highly regulated in adriamycin-cardiomyopathy in rabbits.

Destruction of hematopoietic microenvironment by cytotoxic T cells.

Coculture of cytotoxic T cells (STIL-3 C5) derived from L8313 leukemic mice with hematopoietic supportive stromal cells (MS-5) resulted in the detachment of MS-5 cells from the culture dish, whereas helper T cells (STIL-3 DF) did not induce this detachment. The response of bone marrow (BM) adherent cells to the same treatment was similar to that of MS-5 cells. The detached cells were unable to proliferate further, and genomic DNA of these cells showed fragmentation, suggesting that hematopoietic stromal cells died of apoptosis. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed that STIL-3 C5 cells, but not STIL-3 DF cells expressed perforin, granzyme A & B, and Fas ligand. Fas was expressed in MS-5, BM adherent cells, MS-K and NIH/3T3 cells, which do not support hematopoiesis. These data suggest that the aforementioned factors mediate induction of apoptosis in MS-5 cells induced by direct cell-to-cell interaction with STIL-3 C5. This may explain the mechanism responsible for the destruction of the hematopoietic microenvironment by cytotoxic T cells in L8313 leukemia, from which STIL-3 cells are derived; it also suggests that destruction of hematopoietic tissue may be caused by leukemic cytotoxic T cells in some cases of leukemia.

High-dose chemotherapy for high-risk retinoblastoma: clinical course and outcome of 14 cases in the National Cancer Center, Japan.

The prognosis of high-risk retinoblastoma (RB) with extraocular disease, relapse, or invasion of the cut end of the optic nerve is extremely poor. Following the discontinuation of thiotepa production in Japan, BU- and melphalan (Mel)-based regimens have been used, followed by the standard treatment for neuroblastoma. This study retrospectively analyzed 14 high-risk RB patients who underwent high-dose chemotherapy (HDC) and hematopoietic SCT; 8 received a BU/Mel conditioning regimen and 6 received other regimens. The disease status at HDC was relapse in 8 patients and extraocular involvement in 5. All patients received peripheral blood stem cell infusion >1.5 × 10(6)/kg. Engraftment occurred within a median of 11 days (BU/Mel: 10-13, others: 9-13). Primary toxicities included mucositis (⩾grade 3) in 9 patients (4 with BU/Mel, 5 with others). Veno-occlusive disease (VOD) occurred in two 1-year-old patients in the BU/Mel group. There were no treatment-related deaths. Of 4 (2 with BU/Mel, 2 with others) patients with central nervous system (CNS) relapse after HDC, 3 died. In conclusion, the BU/Mel regimen may be feasible for high-risk RB under careful monitoring for VOD, particularly in younger patients. CNS relapse associated with a lethal prognosis occurred after all regimens; therefore, further evaluation of HDC efficacy for high-risk RB is required.

Quantitative analysis of gene expressions related to inflammation in canine spastic artery after subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: The possible role of inflammatory reaction of the cerebral artery in the pathogenesis of cerebral vasospasm has been noted in recent studies. We quantitatively measured the levels of expression of genes related to inflammation in the spastic artery in a canine double-hemorrhage model. METHODS: Twenty dogs were assigned to 4 groups: group D0, control; group D2, dogs killed 2 days after cisternal injection of blood; group D7, dogs given double cisternal injections of blood and killed 7 days after the first injection; and group D14. Angiography was performed twice: on the first day and before the animals were killed. Total RNA was extracted from the basilar artery. The expressions of interleukin (IL)-1alpha, IL-6, IL-8, IL-10, tumor necrosis factor-alpha, E-secretin, fibronectin, intercellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule-1, transforming growth factor-ss, basic fibroblast growth factor, and collagen types I, III, and IV were examined with TaqMan real-time quantitative reverse transcription-polymerase chain reaction. RESULTS: Prolonged arterial narrowing peaking on 7 day was observed. There was a significant difference in vessel caliber between D0, D2, D7, and D14 groups (P:<0.0001). There were significant differences in mRNA expression in the basilar artery for IL-1alpha, IL-6, IL-8, ICAM-1, and collagen type I between D0, D2, D7, and D14 groups (P:=0.0079, 0. 0196, 0.0040, 0.0017, and <0.0001, respectively). The average level of mRNA was highest in D7 for IL-1alpha, IL-6, IL-8, and ICAM-1 (17-, 16-, 131-, and 1.7-fold compared with those of D0, respectively) and in D14 for collagen type I (10.9-fold). CONCLUSIONS: Increased expression of genes related to inflammation in the spastic artery suggests that inflammatory reaction of the cerebral artery is associated with sustained contraction.

Cardiac ankyrin repeat protein is a novel marker of cardiac hypertrophy: role of M-CAT element within the promoter.

CARP, a cardiac doxorubicin (adriamycin)-responsive protein, has been identified as a nuclear protein whose expression is downregulated in response to doxorubicin. In the present study, we tested the hypothesis that CARP serves as a reliable genetic marker of cardiac hypertrophy in vivo and in vitro. CARP expression was markedly increased in 3 distinct models of cardiac hypertrophy in rats: constriction of abdominal aorta, spontaneously hypertensive rats, and Dahl salt-sensitive rats. In addition, we found that CARP mRNA levels correlate very strongly with the brain natriuretic peptide mRNA levels in Dahl rats. Transient transfection assays into primary cultures of neonatal rat cardiac myocytes indicate that transcription from the CARP and brain natriuretic peptide promoters is stimulated by overexpression of p38 and Rac1, components of the stress-activated mitogen-activated protein kinase pathways. Mutation analysis and electrophoretic mobility shift assays indicated that the M-CAT element can serve as a binding site for nuclear factors, and this element is important for the induction of CARP promoter activity by p38 and Rac1. Thus, our data suggest that M-CAT element is responsible for the regulation of the CARP gene in response to the activation of stress-responsive mitogen-activated protein kinase pathways. Moreover, given that activation of these pathways is associated with cardiac hypertrophy, we propose that CARP represents a novel genetic marker of cardiac hypertrophy.

Age-related structural changes in the human midbrain: an MR image study.

We measured midbrain structures of 194 subjects without neurological disorders, using T2-weighted MR imaging. Age was negatively correlated with the maximum anteroposterior distance of the midbrain through the substantia nigra (MD), and the average distance from the substantia nigra to the red nucleus (SNRND), while a positive correlation was found between aging and the maximum distance of the substantia nigra (SND). Significant left-right differences were revealed in MD, SND, SNRND and the area of the red nucleus (RNA), which was possibly responsible for cerebral hemispheric dominance or handedness. There were gender differences in MD and the maximum interpeduncular distance (IPD) in age-matched groups. Age-related structural changes of the midbrain may have a close relation to a decline in motor performance with aging. These findings provide essential information to evaluate the MR images of neurodegenerative disorders.

Recombinant IFN-gamma treatment of a patient with hyperimmunoglobulin E syndrome triggered autoimmune thrombocytopenia.

We report a pediatric patient with hyperimmunoglobulin E syndrome (HIES) treated with recombinant IFN-gamma (rIFN-gamma) for 2 1/4 years who developed autoimmune thrombocytopenia and was positive for serum antiplatelet antibody and antinuclear antibody (ANA). She was then treated with i.v. methylprednisolone pulse therapy followed by oral immunosuppressive drugs. With this therapy, her platelet count increased and was maintained within the normal range for more than a year. We retrospectively examined her sera stored at -40 degrees C for ANA and found that the ANA level was increased from 1:40 to 1:640 with the rIFN-y therapy. Therefore, we believe that, in this case, rIFN-y treatment may have played a crucial role in triggering autoimmune thrombocytopenia. Furthermore, this case demonstrates that caution must be observed in administering rIFN-gamma to genetically predisposed patients.

Immunoscintigraphy of aortic dissection with 99mTc-labeled murine anti-smooth muscle myosin monoclonal antibody in rats.

UNLABELLED: Aortic dissection is among the most common of fatal conditions of the aorta. Prompt and accurate diagnosis of the site and extent of the lesion is necessary for adequate therapy. However, this catastrophic disease, characterized by extensive damage to smooth muscle cells, lacks specific signs and symptoms. As a result, the diagnosis is still frequently missed today and a new diagnostic method to specifically identify aortic dissection would be attractive. The purpose of this study was to examine the feasibility of radioimmunoscintigraphy using 99mTc-anti-smooth muscle myosin monoclonal antibody (SM-MAb) for the noninvasive diagnosis of aortic dissection in the rat experimental model. METHODS: The accumulation of 99mTc-anti-SM-MAb was studied, and scintigraphic imaging with 99mTc-anti-SMMAb was performed in rats immediately after experimental aortic dissection and 1 and 2 wk later. RESULTS: The radioactivity of 99mTc-anti-SM-MAb in the dissected aorta showed a significant increase compared both with the normal portion of the aorta and with blood 6 h after injection of the radiotracer; the ratio of the percentage injected dose per gram (%lD/g) in the lesion to that retained in the normal portion was 4.17 +/- 1.47. Scintigraphic imaging with 99mTc-anti-SM-MAb allowed distinct visualization of the dissected aorta with specific accumulation of antibody 6 h after tracer injection. Selective accumulation of the tracer in the dissected portion of the aorta persisted even 1 wk after aortic injury, allowing clear visualization of the dissected lesion by scintigraphy. CONCLUSION: Radioimmunoscintigraphy using anti-SM-MAb is a potentially useful noninvasive diagnostic method for imaging aortic dissection.

Cardiac sympathetic activity estimated by 123I-MIBG myocardial imaging in patients with dilated cardiomyopathy after beta-blocker or angiotensin-converting enzyme inhibitor therapy.

UNLABELLED: Impaired cardiac sympathetic activity can be evaluated by 123I-metaiodobenzylguanidine (MIBG) imaging. METHODS: We studied the significance of MIBG imaging for 24 patients (age 58+/-12 y) with dilated cardiomyopathy (DCM). We compared 12 patients (group A) treated with metoprolol (dose from 30-60 mg/d) with 12 patients treated with angiotensin-converting enzyme (ACE) inhibitors. Patients were studied before treatment, after 5 mo of treatment (only in group A) and after 1 y of treatment. Cardiac MIBG uptake was assessed as the heart-to-mediastinum activity ratio (H/M) and total defect score (TDS) from anterior planar and SPECT MIBG images, which were acquired in 4 h after tracer injection. New York Heart Association (NYHA) class and left ventricular ejection fraction (LVEF) calculated by echocardiography were also assessed. RESULTS: TDS decreased in both groups (in group A, from 30+/-7 through 23+/-9 to 18+/-10; P < 0.01, in group B, from 30+/-6 to 24+/-8; P < 0.01) and H/M was increased in both groups (in group A, from 1.87+/-0.31 through 2.03+/-0.28 to 2.14+/-0.29; P < 0.01, in group B, from 1.82+/-0.28 to 1.94+/-0.26; P < 0.05). But TDS and H/M were more improved in group A than in group B (P < 0.05). LVEF was significantly increased in only group A (from 38+/-6 through 43+/-8 to 49%+/-9%; P < 0.01). NYHA improved in both groups (in group A, from mean 2.5 through 2.1 to 1.8; P < 0.01, in group B, from mean 2.6 to 2.1; P < 0.05) but was more improved in group A than in group B (P < 0.05). CONCLUSION: Cardiac function, symptom and cardiac sympathetic activity evaluated by MIBG images improved after the beta-blocker therapy more than with the treatment that used ACE inhibitors.

Comparison of wasting syndrome in [MRL lpr/lpr-->MRL +/+] chimera and graft versus host disease in [B10.D2-->BALB/c] chimera and an attempt to transfer the wasting syndrome in [MRL lpr/lpr-->MRL +/+] to MRL +/+ mice.

We compared the findings in the wasting syndrome seen in [MRL lpr/lpr--> MRL +/+] chimeras with those of chronic graft versus host disease (GVHD) in [B10.D2-->BALB/c] chimeras. BALB/c mice were lethally irradiated and administered B10.D2 spleen and bone marrow cells. These mice are identical to MHC and Mls but differ as to genetic background. As a result of chronic GVHD, these [B10.D2-->BALB/c] chimeras showed hair loss, weight loss and atrophy of lymph nodes and spleen beginning 5 weeks after the transplantation. MRL lpr/lpr mice carry the lpr gene and spontaneously develop generalized lymph node swelling and lupus-like autoimmune disease, while congenic MRL +/+ mice lack the lpr gene. The [MRL lpr/lpr-->MRL +/+] chimeras showed wasting and the same symptoms as in [B10.D2-BALB/c] chimeras beginning 16 weeks after cell transfer. Skin biopsy from both chimeras showed very similar changes on HE staining and on immunoperoxidase staining for Ia and Thy-1. Our data suggest that very small differences in minor histocompatibility may induce GVHD which produces severe wasting with lethal consequences. Finally, we succeeded in transferring the wasting syndrome seen in the [MRL lpr/lpr--> MRL +/+] chimera to other MRL +/+ mice by transplanting spleen cells from the [MRL lpr/lpr-->MRL +/+] chimera to lethally irradiated MRL +/+ mice.

Effects of liposteroid on skin lesions in autoimmune MRLlpr/lpr mice.

Dexamethasone palmitate (D-PAL) incorporated into lipid microspheres (D-PAL emulsion) is taken up by the reticuloendothelial system and by some inflammatory cells. Therefore, it has a stronger anti-inflammatory activity than free corticosteroids in vivo. To study the effect of D-PAL emulsion on systemic lupus erythematosus (SLE), we administered D-PAL emulsion to MRLlpr/lpr mice, an animal model for human SLE. The effect of D-PAL emulsion was compared with that of methylprednisolone (m-PSL), a water-soluble steroid. Percent survival was higher in the group treated with 0.25 mg of D-PAL emulsion intravenously once every 4 weeks than in those groups treated similarly with m-PSL or PBS control. Swelling of lymph nodes was frequent in the group treated with m-PSL or with PBS, while rarely observed in the group treated with D-PAL emulsion. Proteinuria was more frequent in the groups treated with m-PSL or PBS than in the group treated with D-PAL emulsion. Although the frequency of skin lesions was not different between these three groups, the control and m-PSL treated mice had severe skin lesions, such as hair loss of erythematous skin with scales and crusts at the nape, while D-PAL emulsion treated animals showed only facial alopecia without inflammatory skin changes. These data demonstrate that D-PAL emulsion was more effective than a corresponding dose of m-PSL on autoimmune prone mice. This suggests that intermittent administration of D-PAL emulsion may be effective in the treatment of human SLE.

Pulse-Gradient Spin-Echo (1)H, (7)Li, and (19)F NMR Diffusion and Ionic Conductivity Measurements of 14 Organic Electrolytes Containing LiN(SO2CF3)2.

The self-diffusion coefficients of the lithium ion, the anion, and the solvent in lithium bis(trifluromethanesulfonyl)imide (LiTFSI, LiN(SO2CF3)2) solvent systems were measured using the pulse-gradient spin-echo (PGSE) NMR method. Fourteen different organic solvents that are commonly used as organic solution electrolytes in lithium batteries were studied. The self-diffusion coefficients of the corresponding pure solvents were also measured. Since a good correlation between the self-diffusion coefficients of the pure solvents and the inverse of the viscosity was obtained, the results are discussed in terms of the Stokes-Einstein equation. Comparisons of the self-diffusion coefficients of the solvent, the lithium ion, and the anion (TFSI ion) illustrate the solvation behavior for each solvent. The relationship between the ionic conductivity and the sum of the diffusion coefficients of the lithium ion and the anion gives the degree of ion-pair formation and permits the roles of the solvents in the electrolytes to be clearly explained.

Effects of morphine on the distribution of Fos protein in the trigeminal subnucleus caudalis neurons during experimental tooth movement of the rat molar.

The present study was undertaken to disclose temporal changes in the distribution of Fos-like immunoreactive (-IR) neurons in the trigeminal subnucleus caudalis (SpVc), one of the important relay nuclei for processing the nociceptive information from the oro-facial regions, following induction of experimental tooth movement in rat upper molars. Furthermore, the effect of morphine and naloxone on the levels of Fos-IR neurons in the SpVc was examined. The experimental tooth movement was induced by insertion of an elastic rubber between the first and second upper molars. In normal animals, Fos-IR neurons were rarely observed in the SpVc. Immediately after insertion of the elastic band, the distribution of Fos-IR neurons was comparable to that observed in normal animals. The number of Fos-IR neurons increased significantly from 1 to 4 h following the induction of experimental tooth movement, reaching a maximum at 2 h, and then decreasing gradually. Most of the neurons were localized in the dorsomedial portion of the superficial layers of the ipsilateral SpVc near the obex, but a few were observed at the ventral portion of the SpVc. The neurons at the superficial layers and ventral portion of the contralateral SpVc also showed Fos-like immunoreactivity, but their numbers were significantly smaller than those on the ipsilateral side. Pretreatment with morphine (3 and 10 mg/kg, i.p.) significantly reduced the induction of Fos-IR neurons at the superficial layers of the ipsilateral SpVc in a dose-dependent manner, and its effect was antagonized by the subsequent treatment of naloxone (2 mg/kg, i.p.). Naloxone pretreatment enhanced the expression of Fos-IR neurons on the ipsilateral SpVc. The present results of a reduction of Fos-IR neurons by morphine pretreatment suggest that the induction of Fos-IR neurons may be due to the noxious stimulation caused by induction of experimental tooth movement.

Alteration in dopamine metabolism in the thermoregulatory center of exercising rats.

To examine the role of monoamines and amino acids in thermoregulation, we measured their concentrations in the preoptic area and anterior hypothalamus (PO/AH) in exercising rats, using an in vivo microdialysis technique. Body temperature (Tb) was monitored using a telemetry system. Tb increase by about 1.0 degrees C in the first 15 min of treadmill exercise (10 m/min; for 60 min), and was maintained thereafter at a steady high level possibly due to activation of the heat loss system. The levels of dopamine metabolites (3,4-dihydroxyphenylacetic acid and homovanillic acid) in the PO/AH significantly increased during exercise. However, exercise did not induce an increase in the level of either serotonergic substances (5-hydroxytryptamine and 5-hydroxyindoleacetic acid) or amino acids (aspartate and glutamate). Our data indicate that dopamine breakdown processes in the PO/AH are activated during exercise. Dopamine in the PO/AH may be involved in the heat loss mechanisms for thermoregulation when Tb rises during exercise.

The role of preoptic area and anterior hypothalamus and median raphe nucleus on thermoregulatory system in freely moving rats.

To clarify the role of the preoptic area and anterior hypothalamus (PO/AH) on thermoregulatory system and the effects of serotonergic innervation from the median raphe nucleus (MRN) on body temperature (Tb), we perfused tetrodotoxin (TTX) solution into the PO/AH or MRN by using a microdialysis technique at different ambient temperatures (5, 23 and 35 degrees C) in freely moving rats. Tb was continuously monitored by using a telemetry system. In the MRN, perfusion of TTX solution induced significant hypothermia in the normal environment, a greater decrease in Tb during cold exposure and had no effect on Tb during heat exposure. In the PO/AH, perfusion of TTX solution induced significant hyperthermia in normal environment, a greater increase in Tb during heat exposure and had no effect on Tb during cold exposure. Our results indicate that the PO/AH regulates mainly heat loss or inhibits the loci regulating heat production. Furthermore, heat production appears to be regulated by other loci receiving serotonergic innervation from the MRN.