[Traumatic thoracic aortic rupture--diagnosis and surgical repair]

Fifteen cases of traumatic thoracic aortic rupture (TAR) were treated at St. Marianna University Hospital from December 1980 to July 1995. Causes of TAR were due to vehicle accidents in 14 patients and fall in one patient. On diagnosis, contrast-enhanced CT scan was routinely performed in the patients with blunt chest trauma associated with superior mediastinal widening, loss of the aortic knob or right shift of the trachea on the initial roentgenogram. When CT scan demonstrated specific signs for TAR, pseudoaneurysm formation and/or extravasation of the contrast dye, aortography was eliminated before operation. As a role, operation was performed on an emergency basis as soon as the diagnosis was confirmed. Four cases died due to intrapleural rupture before or immediately after thoracotomy. Nine (82%) of the 11 patients in whom operation was completed survived and are doing well. In one of the 4 patients who underwent operation with simple aortic cross-clamping; paraplegia developed after 30 minutes of spinal ischemia. Left heart bypass with the Bio-Pump without heparin or with an antithrombin agent, argatroban, was used in recent 6 patients. Use of left heart bypass with the Bio-Pump without anticoagulant or with argatroban appears to be promising as a safe adjunct in the repair of TAR, preventing fatal bleeding of other injured organs.

Effect of estriol on bone loss in postmenopausal Japanese women: a multicenter prospective open study

OBJECTIVES

To assess the effects of oral estriol on the bone mineral density (BMD) and bone metabolism in postmenopausal women.

METHODS

Seventy-five natural postmenopausal women with a BMD of more than 10% below the peak bone density were treated for 50 weeks with 2 mg/day estriol (E3) cyclically and 0.8 g/day of calcium lactate continuously. BMDs at L2-L4 were measured by dual energy X-ray absorptiometry (DXA).

RESULTS

The BMD increased 1.79% (p < 0.01 vs. pretreatment) after 50 weeks, accompanied with decrease of biochemical markers of bone turnover. With regard to climacteric symptoms, Kupperman's menopausal index improved (p < 0.01 vs. pretreatment) after 5 weeks of treatment. As to the incidence of adverse events genital bleeding was observed in only 8.0% of the subjects. Endometrial histology and cytology showed neither abnormalities nor hyperplasia during and after the treatment.

CONCLUSIONS

Estriol prevented postmenopausal bone loss and improved climacteric symptoms effectively with low incidence of genital bleeding.

[Long-term evaluation of radiographic changes following cervical anterior fusion with hydroxyapatite ceramic spacer]

Cervical anterior fusion with iliac bone crest has become a popular surgical technique for cervical spondylotic disease. Since about 10 years ago, we have substituted hydroxyapatite ceramic spacer for autologous graft because of postoperative painful hip syndrome. Fourteen patients who underwent cervical anterior fusion with ceramic spacer were evaluated by plain radiographs for over eight years postoperatively. In six among the fourteen patients plain films demonstrated minimal stenosis of intervertebral disc height, of which the ratio ranged from 15% to 28% (mean 22%). The increase in mobility of the adjacent segment after fusion was noted in ten of the fourteen patients, although the ratio ranged only between 12% and 24% (mean 18%). In none of all the patients did dynamic plain films show cervical instability such as slippage and swan neck deformity. It seems that anterior fusion with ceramic spacer is a useful and safe method for a cervical spondylotic disease.

Effects of nitric oxide synthesis inhibition on methamphetamine-induced dopaminergic and serotonergic neurotoxicity in the rat brain

We examined effects of nitric oxide (NO.) synthesis inhibition on methamphetamine (MA)-induced dopaminergic and serotonergic neurotoxicity. The toxic dose of MA (5 mg/kg, sc, x4) significantly decreased contents of dopamine (DA), dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the striatum (ST), and significantly decreased contents of serotonin (5-HT) in the ST, nucleus accumbens (NA) and medial frontal contex (MFC). Coadministration with a NO. synthase inhibitor, N omega-nitro-L-arginine methyl ester (LNAME) (30 mg/kg, i.p., x2), reduced the MA-induced decreases in contents of DA, DOPAC and HVA in the ST, but not reduced the MA-induced decreases in contents of 5-HT in the ST, NA and MFC. These findings suggest that the MA-induced dopaminergic, but not serotonergic neurotoxicity, may be related to the neural process such as NO. formation caused by the activation of postsynaptic DA receptor.

Continuous monitoring of short-latency somatosensory evoked potentials during cardiac and aortic surgery

The effectiveness of monitoring somatosensory evoked potentials (SEPs) intraoperatively to detect brain damage early remains controversial. To assess the diagnostic accuracy of this modality, a study was conducted between 1991 and 1994, recording SEPs in 287 consecutive patients undergoing cardiac and aortic surgery using cardiopulmonary bypass (CPB) with moderate hypothermia or deep hypothermic circulatory arrest. From P1 to N2 of the SEPs occurring within 50 ms latency in response to electrical stimulation of the median nerve were recorded over the contralateral postcentral cortex at 5-min intervals using a Neuropack-2 (Nihon Koden, Tokyo, Japan). Normal SEPs were recovered in 247 patients postoperatively; however, 2 of these patients had suffered a cerebral infarction and 1, a transient stroke intraoperatively, demonstrating a false-negative incidence of 1.2%. On the other hand, three different types of abnormal SEPs were recorded postoperatively. P1 and N1 absence, probably caused by a subcortical lesion, was observed in 4 patients; P2 and N2 absence, probably caused by a cortical lesion, was observed in 8 patients; and a flat SEP, representing diffuse damage, was observed in 2 patients. Among these 14 patients with abnormal SEPs, 7 showed no neurologic disturbance at all, demonstrating a false-positive incidence of 50%. Thus, we concluded that when normal SEPs are recovered during weaning from CPB, the incidence of brain damage could be predicted at below 5%. Conversely, when abnormal SEPs are demonstrated, the incidence of brain dysfunction impeding a return to active life is estimated to be about 70%.

Conversion from farnesyl diphosphate synthase to geranylgeranyl diphosphate synthase by random chemical mutagenesis

Prenyltransferases catalyze the consecutive condensation of isopentenyl diphosphate (IPP) with allylic diphosphates to produce prenyl diphosphates whose chain lengths are absolutely determined by each enzyme. In order to investigate the mechanisms of the consecutive reaction and of the determination of ultimate chain length, a random mutational approach was planned. The farnesyl diphosphate (FPP) synthase gene of Bacillus stearothermophilus was subjected to random mutagenesis by NaNO2 treatment to construct libraries of mutated FPP synthase genes on a high-copy plasmid. From the libraries, the mutants that showed the activity of geranylgeranyl diphosphate (GGPP) synthase were selected by the red-white screening method (Ohnuma, S.-i., Suzuki, M., and Nishino, T. (1994) J. Biol. Chem. 268, 14792-14797), which utilized carotenoid synthetic genes, phytoene synthase, and phytoene desaturase, to visualize the formation of GGPP in vivo. Eleven red positive clones were identified from about 24,300 mutants, and four (mutant 1, 2, 3, and 4) of them were analyzed for the enzyme activities. Results of in vitro assays demonstrated that all these mutants produced (all-E)-GGPP although the amounts were different. Each mutant was found to contain a few amino acid substitutions: mutant 1, Y81H and L275S; mutant 2, L34V and R59Q; mutant 3, V157A and H182Y; mutant 4, Y81H, P239R, and A265T. Site-directed mutagenesis showed that Y81H, L34V, or V157A was essential for the expression of the activity of GGPP synthase. Especially, the replacement of tyrosine 81 by histidine is the most effective because the production ratios of GGPP to FPP in mutant 1 and 4 are the largest. Based on prediction of the secondary structure, it is revealed that the tyrosine 81 situates on a point 11 approximately 12 A apart from the first DDXXD motif, whose distance is similar to the length of hydrocarbon moiety of FPP. These data might suggest that the aromatic ring of tyrosine 81 blocks the chain elongation longer than FPP. Comparisons of kinetic parameters of the mutated and wild type enzymes revealed several phenomena that may relate with the change of the ultimate chain length. They are a decrease of the total reaction rate, increase of Kmfor dimethylallyl diphosphate, decrease of Vmax for dimethylallyl diphosphate, and allylic substrate dependence of Km for IPP.

Synthesis and application of boronic acid-immobilized porous polymer particles: a novel packing for high-performance liquid affinity chromatography

A preparation method of a novel type of packing materials for high-performance liquid affinity chromatography to determine glycated proteins was studied, and a fundamental study on its application to diabetic serum was conducted. To quantify glycated proteins such as glycated serum albumin, a new hydrophilic and durable porous polymer particle recently developed in our laboratory was used as the basic matrix. The matrix was activated with 1,1'-carbonyldiimidazole (CDI), and optimization of the coupling reaction between these CDI-activated matrix and m-aminophenylboronic acid hemisulfate (APBA) as affinity ligand was investigated. The optimum value for the APBA coupling yield was found to be obtained under acidic conditions very different from the data reported by previous workers. Using this APBA-immobilized matrix an affinity column was prepared, and its usefulness in HPLC separation of glycated serum proteins was investigated. Also, the fundamental and preliminary results for diagnosis of diabetes mellitus are discussed in this paper.

Functional coupling between metabotropic glutamate receptors and G proteins in rat brain membranes

Functional activation of GTP-binding (G) proteins coupled with metabotropic glutamate receptors was evaluated in rat brain membranes. L-Glutamate stimulated the high-affinity GTPase activity in cerebral cortical, hippocampal, and striatal membranes with a mean concentration eliciting a half-maximal response (EC50) of 4.8, 1.6, and 4.9 microM, respectively. The enzyme activity in cerebral cortical membranes was also stimulated by (2S, 1'S,2'S)-2-(carboxycyclopropyl)glycine (L-CCG-I) with a mean EC50 of 0.90 microM, but not by L-2-amino-4-phosphonobutyrate (L-AP4) up to 10 microM. This method opens up a strategy for investigation of functional coupling between Group II metabotropic glutamate receptors and G proteins in native brain membranes.

Effect of the selective CCKB receptor antagonist LY288513 on conditioned fear stress in rats

In order to investigate the involvement of cholecystokinin (CCK) in the regulation of anxiety, the effect of the selective non-peptide CCKB receptor antagonist LY288513 ((4S, 5R)-N-(4-bromophenyl)-3-oxo-4,5-diphenyl-1-1-pyrazolidinecarboxamide+ ++) on freezing behavior induced by conditioned fear stress was examined using a time-sampling procedure. Rats were individually subjected to 5 min of inescapable electric footshock in a shock chamber. Twenty-four hours after the footshock, the rats were again placed in the shock chamber and observed for 5 min without shocks: this procedure is termed conditioned fear stress. Subcutaneous administration of LY288513 30 min before footshock (0.3 mg/kg) and 30 min before conditioned fear stress (0.03 mg/kg) reduced conditioned freezing. This indicates that LY288513 blocked both the acquisition and expression of conditioned fear. The relatively selective non-peptide CCKA receptor antagonist, lorglumide (D, L-4-(3,4-dichlorobenzoylamino)-5-(diphentylamino)-5-oxo-pent anoic acid), blocked the expression of conditioned fear, though only at a high dose (1.0 mg/kg). The peripheral non-peptide CCKA/B receptor antagonist, loxiglumide (D, L-4-(3,4-dichlorobenzoylamino)-5- (N-3-methoxypropyl-pentylamino)-5-oxo-pentanoic acid), failed to do so. These results suggest that brain CCKB receptors are involved in the regulation of anxiety.

[Clinical analysis of embolism with left atrial myxomas]

We conducted a retrospective analysis examining the relationship between the tumor quality and the occurrence of systemic embolization in 16 patients who underwent surgical excision of the left atrial myxoma. Systemic embolization occured in 10 patients (63%) before surgery, in 5 of whom embolic episodes were the first manifestation of the tumor. Cerebral infarction had developed in 7 patients, TIA in 2, myocardial infarction in 2, limb ischemia in 2, and multiple infarctions in the kidney, adrenal gland, spleen and bone marrow in one. A permanent deficit remained in 6 patients (60%). Myxoma was a lobulated and gelatinous type in 9 (90%) of these patients with embolization and a solid type only in one case. When the dignosis of the left atrial myxoma with soft and fragile quality is made by echocardiography, surgical excision should be performed without delay to prevent systemic embolization.

Serotonergic activation reduces defensive freezing in the conditioned fear paradigm

Our previous study showed that conditioned fear stress (CFS) increased serotonin (5-HT) metabolism in the medial prefrontal cortex and induced freezing behavior. Although these results could support the 5-HT hypothesis of anxiety, the functional significance of the 5-HT response to stress is unclear. In this study, the effects of 5-HT reuptake inhibitors, agonists, antagonists, and diazepam on freezing behavior induced by CFS were examined using a time-sampling procedure. Various doses of test compounds were administered subcutaneously to rats 24 h after the last session of repeated foot-shock for 5 days. Rats were again placed in the shock chamber without shocks 20 min after injections of drugs, and observed. Diazepam (1 mg/kg) and the 5-HT1A agonist ipsapirone (0.5-10 mg/kg) significantly inhibited freezing behavior. L-5-Hydroxytryptophan (with benserazide) and the selective 5-HT reuptake inhibitor citalopram (10 mg/kg) reduced freezing behavior. The 5-HT2 antagonists ICI169,369 and ketanserin failed to change freezing behavior. p-Chlorophenylalanine (200 mg/kg) administered 15 h before the test did not affect freezing. The effect of ipsapirone was not modified in rats with lesions of 5-HT neurons, produced by p-chloroamphetamine (2 x 10 mg/kg). In conclusion, these results suggest the anxiolytic potential of ipsapirone and citalopram, and support the hypothesis that the facilitation of 5-HT neurotransmission decreases anxiety.

[Far lateral lumbar disc herniation: clinical and radiographical features of three cases]

The authors report three operated cases of far lateral lumbar disc herniation (FLLDH) during the past two years and discuss their diagnostic pitfalls. Until recently FLLDH was hardly ever diagnosed because the myelography was negative in almost all cases. Since the advent of CT and/or MRI, FLLDH has been found to be not such a rare entity. FLLDH has also been found to reveal characteristic clinical features and radiographical findings. Usual lumbar disc herniations occur at L4/5 or L5/S1 levels, producing low back pain with the pain or sensory disturbance from the posterolateral thigh down to the foot. In contrast, FLLDH affects upper lumbar levels and produces severe anterolateral thigh pain, dysesthesia resulting from nerve root or dorsal root ganglion (DRG) compression in the foraminal or extraforaminal region. The level predilection of these two groups can be attributed to the difference of the facet joint planes between the upper and lower lumbar levels. The facets with a coronal plane are resistant to lateral bending and rotational forces, but those with a sagittal plane are unstable resulting in more shearing stress to the intervertebral discs. A patient with definite neurological signs but a negative myelography should be examined for FLLDH by using a high-resolution CT or MRI. MRI clearly shows the detailed anatomical relationships between herniated disc and nerve root or DRG in the foraminal and extraforaminal regions. As well as thin-sliced axial images, sagittal MR images that include the foraminal zone are useful for detecting a direct nerve root compression from FLLDH. The authors conclude that gait disturbance due to severe leg pain, antero-lateral thigh pain or dysesthesia are characteristic of FLLDH, and that either a foraminal or extraforaminal herniated disc or both on a CT and/or MRI are diagnostic radiographical findings of FLLDH.

Ethylene-induced gene expression of osmotin-like protein, a neutral isoform of tobacco PR-5, is mediated by the AGCCGCC cis-sequence

Osmotin-like protein (OLP) is a neutral isoform in the group 5 pathogenesis-related (PR) tobacco proteins. The OLP gene, like the basic PR protein genes, is constitutively expressed in tobacco roots and cultured cells. OLP is not naturally present in intact healthy leaves, but ethylene treatment induces a high accumulation there. To study the mechanism of OLP gene expression as induced by ethylene, we cloned the gene from Nicotiana sylvestris, an ancestor of N. tabacum. Sequence analysis showed that it has no intron and that its promoter region contains two AGCCGCC sequences that are conserved in most basic PR-protein genes. The function of the AGCCGCC sequences in transgenic tobacco plants that harbor the wild and mutated OLP promoter::GUS fusion genes was analyzed. Mutation in the AGCCGCC sequences clearly inhibited the GUS expression induced by ethylene, indicative that the AGCCGCC sequence(s) is a DNA element(s) responsive to ethylene. An EREBP2 protein, isolated as one of the proteins binding to the AGCCGCC sequence of the tobacco beta-1,3-glucanase gene, also was found to bind to the AGCCGCC sequence(s) of OLP gene. These results suggest that the ethylene-induced expression of OLP is regulated by a trans-acting factor(s) common to basic PR-proteins.

Studies of the pathogenesis and management of thrombotic thrombocytopenic purpura

We have studied the pathophysiological signs and methods of management of thrombotic thrombocytopenic purpura (TTP) in our TTP patients. We showed that anti-platelet GP II b- III a monoclonal antibodies bound to human vascular endothelial cells (HUVEC). The binding rate of 125I-anti-platelet GP II b- III a monoclonal antibodies to HUVEC treated with TTP patients sera was decreased, compared with the value observed for HUVEC treated with normal sera. These findings showed that GP II b- III a like substances are expressed on HUVEC and that TTP patients sera appear to contain anti-platelet GP II b- III a antibodies which may attack and injure the endothelial cells. PGI2 stabilizing activity of plasma is measured by PGI2 inhibitory activity attenuation on normal platelet aggregation induced by ADP. PGI2 stabilizing activity decreases in acute phase, increases in remission, suggesting that there may be a relationship between pathogenesis of TTP and decreases of PGI2 stabilizing activity. We also showed that PGI2 analogue (beraprost sodium) was useful for prevention of relapse of TTP. Plasmapheresis has emerged as the treatment of choice of TTP. We found the effectiveness of the high molecular weight fraction (HMW-F) of plasma in chronic TTP patients. HMW-F of plasma may contain the main factor necessary for improvement of TTP.

[Spondylodiscitis after operation for lumbar disc herniation]

Postoperative spondylodiscitis (POD) is a rare but severe complication of lumbar disc surgery. There were five patients with POD among 875 patients undergoing surgery for herniated lumbar discs, in the last 16 years. For detecting risk factor of discitis, a POD group of 5 patients was matched to a control group of 870 patients with respect to sex, age, disc type and operation. In five patients with POD follow-up evaluation of clinical symptoms, laboratory data were obtained, and magnetic resonance (MR) imaging was performed. A significant difference between the POD group and the control group was confirmed in sex, operation time and the volume of bleeding during operation. However, there was no significant difference confirmed due to age, disc type, disc level and operative procedure. In the case of males or prolonged operation time or increase of the volume of bleeding, POD may be more frequently observed. All five patients had a period of pain relief after their operations and then reported increasing low back pain with no focal signs. At diagnosis of POD all patients had an erythrocyte sedimentation rate (ESR) greater than 30 per hour and C-reactive protein (CRP) higher than 2.5. After treatment by antibiotics, low back pain gradually receded along with decrease of ESR and CRP. About 40 days later, these patients were almost free of back pain and ESR and CRP were within normal range. MRT1-weighted image during the acute phase demonstrated remarkably decreased signal intensity with loss of distinction between vertebral body and disc space. T2-weighted image showed increased signal intensity in the adjacent vertebral bodies and end-plates. Gadolinium-enhanced T1-weighted image had homogenous enhancement of vertebral body and disc space. During the subacute phase, however, T1-weighted image demonstrated moderately decreased signal intensity noted in the posteroinferior portion of the L5 vertebral body and the narrowed L5/S1 disc space. T2-weighted image showed iso signal intensity in L5 and S1 vertebral bodies. Gadolinium-enhanced T1-weighted image had mild homogenous enhancement in the posteroinferior portion of the L5 vertebral body. Three months after treatment of POD, there was major signal change in neither T1 nor T2 weighted images, though T2 showed subtle abnormalities with decreased signal intensity adjacent to the L5/S1 disc space.

Anticoagulant effects of retinoic acids on leukemia cells

We have recently found that all-trans retinoic acid (ATRA) upregulates thrombomodulin (TM) and downregulates tissue factor (TF) expression in acute myelogenous leukemia (AML) M3 cells (NB4) and acute monoblastic leukemia cells (U937) (Koyama et al, Blood 84:3001, 1994). We have further investigated the effects of ATRA on leukemic cells freshly isolated from patients at diagnosis. Increase of TM antigen was documented in all AML cells: M0 (n = 1), M2 (n = 5), M3 (n = 3), M4 (n = 3), M5 (n = 3), and M6 (n = 1). Decrease of TF antigen was observed in 4 M2, 1 M4, and all M3 and M5 patients. However, no TM and TF antigens were detected in all chronic lymphocytic leukemia cells (n = 3) with or without ATRA treatment. Changes of TM and TF antigen levels were associated with those of TM and TF cofactor levels on the cell surface. A stereoisomer of RA, 9-cis RA, is a high-affinity ligand for the RA receptors (RARs) and the retinoid X receptors, although ATRA and another isomer, 13-cis RA, solely bind to RARs. We have also studied the effects of 9-cis RA and 13-cis RA on the expressions of TM and TF in NB4 and U937 cells. A relatively wide range of 9-cis RA concentrations (0.01 to 1 mumol/L) compared with ATRA was optimal for prolongation of normal plasma-based recalcification time (reduction of cell surface TF activity), decrease of TF antigen, and increase of TM antigen on the surface and in the lysates of NB4 and U937 cells. Western blot analysis under nonreducing conditions showed that both ATRA and 9-cis RA markedly induced the prominent band at 75 kD of TM and reduced the band at 45 kD of TF. Northern blot analysis has shown similar changes of mRNA levels, which indicates that RAs regulate TM and TF expression in leukemic cells at transcriptional levels. Anticoagulant effects of ATRA, ie, upregulation of TM expression and downregulation of TF expression, are applied not only to established cell lines of specific subtypes (M3 and M5) but also to more universal AML (most cases of M3 and M5 and a part of the other types of AML) cells freshly isolated from patients. 9-cis RA may be more effective than ATRA as an inducer of differentiation of AML M3 cells and as an anticoagulant agent for patients with certain types of AML as well.

[The influence of pregnancy and delivery on the climacteric symptoms]

This study was undertaken to investigate the influence of past pregnancy and delivery on the perimenopausal status in 144 women (48-52 years of age). Individual interviews to ascertain the personal profile, medical history, events at pregnancy, delivery and puerperium, and the kind and severity of climacteric symptoms were held. The subjects were divided into two groups by means of a simplified menopausal index (SMI): group A had climacteric symptoms (SMI > 50) and those in group B had mild symptoms (SMI < or = 50). The analysis of the principal components, and the correlation among the variables revealed that three factors--the impression and events at past pregnancies and deliveries, reproductive functions, and the psycho-character properties--had a significant influence on the status at the perimenopause, but the social-environmental factors appeared to have no significant influence on the severity of climacteric symptoms.

Serotonin reuptake inhibitors reduce conditioned fear stress-induced freezing behavior in rats

Conditioned fear stress (CFS)-induced freezing behavior has been proposed as an animal model of anxiety. In the present study, freezing was used to determine the anxiolytic activity of selective serotonin reuptake inhibitors (SSRIs), which are reported to be clinically effective in anxiety disorders. The duration of freezing behavior was reduced by acute treatment with the SSRIs citalopram (1-10 mg/kg) and fluvoxamine (3-30 mg/kg). Acute treatment with the serotonin (5-HT)/noradrenaline (NA) mixed reuptake inhibitor milnacipran (3-30 mg/kg) also attenuated CFS-induced freezing, while acute treatment with the NA reuptake inhibitors maprotiline and ORG4428, and the dopamine (DA) reuptake inhibitor GBR12909 failed to alter CFS-induced freezing. These results indicate that facilitation of 5-HT availability in the brain produced by 5-HT reuptake inhibition reduces CFS-induced freezing behavior. CFS may be a useful model for detecting the anxiolytic potential of 5-HT reuptake inhibitors.

Effects of acute and chronic administration of high-dose corticosterone and dexamethasone on regional brain dopamine and serotonin metabolism in rats

1. The effects of acute and chronic treatment with high-dose corticosterone (50 mg/kg) and dexamethasone (0.7 mg/kg) on monoamines and their metabolites levels in four regions of the rat brain were investigated. 2. Acute corticosterone and dexamethasone treatment decreased serotonin (5-HT) levels, but did not alter dopamine (DA),3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) or 5-hydroxyindoleacetic acid (5-HIAA) levels in any of the brain regions. 3. Chronic corticosterone treatment significantly increased the HVA and 5-HIAA levels only in the medial prefrontal cortex, while chronic dexamethasone treatment did not alter. Chronic corticosterone and dexamethasone treatment did not change DA, DOPAC or 5-HT levels in any of the brain regions. 4. These findings suggest that chronic treatment with high-dose corticosterone activates the dopaminergic and serotonergic neurotransmission in the medial prefrontal cortex.