Biomedical subjects

K Imamura

Publications and source records attributed to K Imamura.

At least 19 recordsLinked to original sources

PubMed2006

Cellular and subcellular localization of alpha-1 adrenoceptors in the rat visual cortex.

Noradrenaline is thought to play modulatory roles in a number of physiological, behavioral, and cellular processes. Although many of these modulatory effects are mediated through alpha-1 adrenoceptors, basic knowledge of the cellular and subcellular distributions of these receptors is limited. We investigated the laminar distribution pattern of alpha-1 adrenoceptors in rat visual cortex, using immunohistochemistry at both light and electron microscopic levels. Affinity-purified anti-alpha-1 antibody was confirmed to react only with a single band of about 70-80 kDa in total proteins prepared from rat visual cortex. Alpha-1 adrenoceptors were widely distributed though all cortical layers, but relatively high in density in layers I, II/III, and V. Immunoreactivity was observed in both neuronal perikarya and processes including apical dendrites. In double-labeling experiments with anti-microtubule-associated protein 2, anti-neurofilament, anti-glial fibrillary acidic protein, anti-glutamic acid decarboxylase 65/67, anti-2-3-cyclic nucleotide 3-phosphodiesterase, and anti-tyrosine hydroxylase antibodies, alpha-1 adrenoceptors were found mainly in dendrites and somata of microtubule-associated protein 2-immunopositive neurons. About 20% of alpha-1 adrenoceptors were in GABAergic neurons. A small number of alpha-1 adrenoceptors were also distributed in axons of excitatory neurons, astrocytes, oligodendrocytes and noradrenergic fibers. Using an immunoelectron microscopic technique, numerous regions of alpha-1 adrenoceptor immunoreactivity were found in cell somata, on membranes of dendrites, and in postsynaptic regions. Moreover, a small number of immunoreaction products were also detected in axons and presynaptic sites. These findings provide the first quantitative evidence regarding the cellular and subcellular localization of alpha-1 adrenoceptor immunoreactivity in visual cortex. Moreover, the ultrastructural distribution of alpha-1 adrenoceptor immunoreactivity suggests that alpha-1 adrenoceptors are transported mainly into dendrites and that they exert effects at postsynaptic sites of neurons.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗

PubMed2006

The useful combination of a higher frequency miniprobe and endoscopic submucosal dissection for the treatment of T1 esophageal cancer.

BACKGROUND: There are few published data on the discrimination ability of endoscopic ultrasonography (EUS) among each subdivision of T1 cancer, and overdiagnosis is an unsolved problem that eventually causes overtreatment. The purpose of this study was to verify whether our treatment strategy incorporating EUS realizes a tailored patient management of T1 esophageal cancer. METHODS: This study comprised 20 esophageal cancer patients undergoing 12- to 20-MHz miniprobes for T staging and a 7.5-MHz dedicated echoendoscope for N staging. Initial therapy constituted endoscopic submucosal dissection (ESD) for endosonographically node-negative, mucosal, or slight submucosal cancers and a primary esophagectomy with three-field lymphadenectomy for deeper cancers. If the ESD specimen revealed no cancer involvement of the muscularis mucosa, the patients entered a follow-up program; otherwise, they were advised to undergo a subsequent esophagectomy and three-field lymphadenectomy. RESULTS: Perfect discrimination accuracy was achieved among T1, T2, and T3 cancers. Whether cancer depth was up to the slight submucosal layer or deeper was correctly differentiated in 12 of 14 T1 cancers (86%). EUS categorized all patients correctly into candidates for either ESD or surgery. The pathological cancer depth of the resected specimens revealed that no patients experienced unnecessary overtreatment. CONCLUSIONS: A higher frequency miniprobe is useful for the detailed evaluation of cancer depth, contributing to decision making for treatment options of T1 esophageal cancer. A miniprobe and echoendoscope in combination with ESD provide an appropriately tailored management plan on an individual basis, avoiding unnecessary treatment or indicating radical surgery.

Adenocarcinoma↗

PubMed2006

Manipulation of the small intestine as a cause of the increased inflammatory response after open compared with laparoscopic surgery.

BACKGROUND: Laparoscopic surgery of the gastrointestinal tract involves a reduced immune response compared with open surgery. The aim of this study was to assess manual handling of the gut in open procedures as the principal cause of the enhanced immune response. METHODS: Eighteen Landrace pigs underwent gastrectomy by three different methods: conventional open wound with bowel manipulation, laparoscopically assisted gastrectomy, and gastrectomy without manipulation using a combination of open wound and laparoscopic surgical devices. Local inflammatory changes were assessed by ascites formation, intestinal adhesion development and intestinal inflammatory gene expression. Associated systemic inflammatory changes were determined by measuring portal and systemic plasma endotoxin levels, plasma inflammatory cytokine levels, liver inflammatory gene expression and transaminase levels. RESULTS: Significantly more postoperative intra-abdominal fluid and adhesions were seen in the open group. The expression of inflammatory cytokines was significantly greater in the intestine and liver in the open group. Portal and systemic levels of endotoxin, inflammatory cytokines and transaminases were also higher. CONCLUSION: Manual handling of organs during gastrectomy is an important contributor to the molecular and humoral inflammatory response to surgery, supporting the use of minimally invasive techniques in gastrointestinal surgery.

Animals↗

PubMed2006

Role of cytokines in inflammatory process in Parkinson's disease.

We investigated whether the cytokines produced in activated microglia in the substantia nigra (SN) and putamen in sporadic Parkinson's disease (PD) are neuroprotective or neurotoxic. In autopsy brains of PD, the number of MHC class II (CR3/43)-positive activated microglia, which were also ICAM-1 (CD 54)-, LFA-1 (CD 11a)-, TNF-alpha-, and IL-6-positive, increased in the SN and putamen during progress of PD. At the early stage activated microglia were mainly associated with tyrosine hydroxylase (TH)-positive neurites in the putamen, and at the advanced stage with damaged TH-positive neurons in the SN. The activated microglia in PD were observed not only in the nigro-striatal region, but also in various brain regions such as the hippocampus and cerebral cortex. We examined the distribution of activated microglia and the expression of cytokines and neurotrophins in the hippocampus of PD and Lewy body disease (LBD). The levels of IL-6 and TNF-alpha mRNAs increased both in PD and LBD, but those of BDNF mRNA and protein drastically decreased specifically in LBD, in which neuronal loss was observed not only in the nigro-striatum but also in the hippocampus. The results suggest activated microglia in the hippocampus to be probably neuroprotective in PD, but those to be neurotoxic in LBD. As an evidence supporting this hypothesis, two subsets of microglia were isolated from mouse brain by cell sorting: one subset with high production of reactive oxygen species (ROS) and the other with no production of ROS. When co-cultured with neuronal cells, one microglia clone with high ROS production was neurotoxic, but another clone with no ROS production neuroprotective. On the other hand, Sawada with coworkers found that a neuroprotective microglial clone in a culture experiment converted to a toxic microglial clone by transduction of the HIV-1 Nef protein with increasing NADPH oxidase activity. Taken together, all these results suggest that activated microglia may change in vivo from neuroprotective to neurotoxic subtsets as degeneration of dopamine neurons in the SN progresses in PD. We conclude that the cytokines from activated microglia in the SN and putamen may be initially neuroprotective, but may later become neurotoxic during the progress of PD. Toxic change of activated microglia may also occur in Alzheimer's disease and other neurodegenerative diseases in which inflammatory process is found.

Animals↗

PubMed2004

A seasonal variation in the onset of postoperative adhesive small bowel obstruction is related to changes in the climate.

BACKGROUND: Postoperative small bowel obstruction following abdominal procedures is more common in patients who have undergone laparotomy. However, little is known about the influence of climate on the incidence of postoperative small bowel obstruction. METHODS: To evaluate whether seasonal climatic variations are a risk factor for postoperative small bowel obstruction, hospital-based, retrospective case series was designed from medical records of 230 patients suffering from postoperative small bowel obstruction admitted to the Tokyo University Branch Hospital. Detailed analysis of weather charts from the Japanese Meteorological Agency and review of medical records for selected patients who were diagnosed with postoperative small bowel obstruction. The obstruction was diagnosed by abdominal X-ray imaging, clinical examination, and patient interviews. RESULTS: A total of 233 patients diagnosed with postoperative small bowel obstruction were identified. Analysis of the medical records of these 233 patients revealed that the variables associated with an increased risk of postoperative small bowel obstruction included low ambient temperatures of 5-10 degrees C, an increase in air humidity by 40-50% and air pressure of 1010-1015 hPa. CONCLUSION: The typical winter weather in Tokyo is characterised by low temperatures, low humidity and moderate air pressure. These winter climate conditions could be correlated with an increased incidence of postoperative small bowel obstruction in Tokyo during our period.

Adolescent↗

PubMed2004

[Evaluation of sternal deformity after pediatric minimally invasive cardiac surgery].

Sternal shape is one of the most important esthetic factors of the chest appearance after pediatric minimally invasive cardiac surgery (pMICS) as well as length of skin wound. We evaluated the grade of postoperative sternal deformity in 20 patients who underwent total repair of pediatric congenital heart disease [atrial septal defect (ASD): 17, ventricular septal defect (VSD): 2, partial anomalous pulmonary venous connection (PAPVC): 1] with minimal skin incision and lower partial median sternotomy. The sternum was closed with stainless wire in 3 patients, with absorbable polydioxanone (PDS) cord in 5 patients, with combined use of reabsorbable radiolucent poly (L-lactate) acid sternal pin and absorbable PDS cord in 12 patients. The evaluation of postoperative sternal deformity was made according to the vertebral index (VI) and frontosagittal index (FSI) in 3 groups with each sternal closure method. VI and FSI of the 3 groups showed no significant difference. Sternal deformity in the group with sternal closure with PDS cord group was more severe than that in other 2 groups. The combined use of sternal pin with PDS cord offered the most sufficient fixative strength for sternal closure.

Absorbable Implants↗

PubMed2003

Survey of nasal colonization by, and assessment of a novel multiplex PCR method for detection of biofilm-forming methicillin-resistant staphylococci in healthy medical students.

We surveyed the prevalence of nasal colonization by biofilm-forming methicillin-resistant staphylococci in healthy medical students, who had never had contact with patients, using polymerase chain reaction (PCR) to detect themec A gene, production of penicillin-binding protein 2' (PBP2'), and quantitative assay of biofilm formation on polystyrene. Anterior nasal swabs from 90 students were cultured on mannitol salt and oxacillin salt screening agar plates. In total, 231 staphylococcal isolates belonging to 10 species from 88 students were identified, of which 139 from 77 (88%) students were Staphylococcus epidermidis. The overall prevalences of methicillin-resistant and biofilm-forming staphylococci were 48% (43 of 90) and 59% (53 of 90) for the medical students, respectively. In total 30 (33%) students carried biofilm-forming methicillin-resistant staphylococci in the nares, all of which were identified as S. epidermidis. For rapid detection of biofilm-forming methicillin-resistant S. epidermidis (MRSE), we devised a novel multiplex PCR method to assess a total of 243 staphylococcal isolates, including the 231 isolates from the students. The multiplex PCR assay used six primers to amplify atl E and ica ADB, which are responsible for the biofilm formation ofS. epidermidis, and mec A genes. The multiplex PCR assay revealed that 68 (96%) isolates were detectable in 71 biofilm-forming MRSE isolates, which corresponded to 93% (28 of 30) of biofilm-forming MRSE carriers. Surveillance of nasal colonization with biofilm-forming MRSE using this multiplex PCR in healthcare workers and patients, might provide useful information for the establishment of infection control procedures toward biofilm-forming MRSE.

Adult↗

PubMed2002

Hyperstable U1snRNA complementary to the K-ras transcripts induces cell death in pancreatic cancer cells.

One of the critical steps that governs the inhibitory effect of antisense RNA on target gene expression is the association of the antisense RNA with the target RNA molecules. However, until now, no systematic method has been available to select the suitable parts of a gene as antisense targets. In this study, we utilised U1 small nuclear RNA (snRNA) that binds physiologically to the 5' splice site (5'ss) of pre-mRNA, to develop a novel vector system that permits imposed binding of antisense RNA to its target. The 5' free end of U1snRNA was replaced with the antisense sequence against the K-ras gene to generate a hyperstable U1snRNA, whose binding stability to 5'ss of the K-ras transcript is ten-fold higher than that of wild-type U1snRNA. The efficacy of such hyperstable U1snRNA was examined by transducing the expression plasmids into human pancreatic cancer cell lines. This revealed that two of the hyperstable U1snRNAs induced cell death after gene transduction, and significantly reduced the number of G418-resistant colonies to less than 10% of the controls. Furthermore, hyperstable U1snRNA suppressed intraperitoneal dissemination of pancreatic cancer cells in vivo. Hyperstable U1snRNA might be a novel approach to express effective antisense RNA in target cells.

Animals↗

PubMed2002

Long-term adaptation to prism-induced inversion of the retinal images.

For 1 week, healthy human participants ( n=7) were devoid of normal vision by exposure to prism lenses that optically rotated their perceived world around the line of sight by 180 degrees. Adaptation to such prisms involved sustained and vigorous practice of the ability to redirect the unadapted efferent motor command; because prior to all visually guided movements, the to-be-executed efferent command was based on incorrect (prismatically reversed) spatial information. The time course of this sort of adaptation was systematically explored in Cooper-Shepard mental rotation (MR) tests and in naturalistic motor-tasks for the purpose of investigating whether mental rotations of the direction of the intended movement share common aspects with the process of MR. A control group ( n=7) intermittently exposed to the distorted spatial organization of the central visual field was studied in parallel. The main results were as follows: (a) the MR reaction times (RTs) day 1 with prisms appeared to be very similar to the normal RTs (day 1, no-prisms) with the one exception that subjects now responded within a prism (rotated) frame of spatial reference rather than within the environmentally upright. The visuomotor performance became grossly irregular and dysmetric. (b) The majority of the visuomotor adaptation functions began to level off on the 3rd day. (c) The increases in natural motor proficiency were accompanied by a systematic and noticeable decrease in magnitude of the MR Y-intercept obtained from the linear regression line calculated between each subject's RT and the various stimulus angles. MR slopes were stable through days 1-7 for both the experimental and control group. An increased correlation between rotational stimulus angle and RT suggested that the MR function also became progressively more tightly coupled to the stimulus angles. (d) Postadaptation measures of performance indicated the occurrence of selective and minimal adaptation in the natural motor tasks only. It is suggested that these results reflect an improved attentional (strategic) ability to replace incorrect (error producing) control signals with correct (error reducing) control signals. As a result, perceptual-motor start-up processes directly related to spatial coding and to the planning, initiation and correction of the intended direction of motor-or-mental movement improved while the subprocess ("stage") concerned with transformations of such movements remained unchanged. Visuomotor adaptation to inverting prisms engages, and thereby stimulates, a cortical system also invoked in the preparatory process of MR.

Adaptation, Physiological↗

PubMed2002

Perimesencephalic nonaneurysmal subarachnoid haemorrhage and variations in the veins.

Perimesencephalic nonaneurysmal subarachnoid haemorrhage (PN-SAH) is characterised by accumulation of blood around the midbrain, normal angiographic findings and an excellent prognosis. The etiology of PN-SAH has not yet been determined. Therefore we decided to compare the venograms of patients with PN-SAH with those of patients with aneurysmal SAH (A-SAH) in order to examine the relationship between PN-SAH and venous structures. We retrospectively studied 6 patients with PN-SAH and 102 cases of angiographically evaluated A-SAH during the past 12 years by reviewing their venograms for possible abnormalities in venous structures, particularly in the basal vein of Rosenthal (BVR). More abnormalities in venous structures were found in the patients with PN-SAH than in those with A-SAH. Most of the BVR in the patients with PN-SAH appeared to drain into various dural sinuses instead of the galenic system. The relationship between PN-SAH and abnormalities in venous structures was determined.

Aged↗

PubMed2001

Hydrogen-bond network in cyclodecaamylose hydrate at 20 K; neutron diffraction study of novel structural motifs band-flip and kink in alpha-(1-->4)-D-glucoside oligosaccharides.

A single-crystal neutron diffraction study of cyclodecaamylose (CA10) was carried out at 20 K. CA10 crystallizes with 27.18 water molecules [(C(6)H(10)O(5))(10).27.18H(2)O] in space group C2 with unit-cell constants a = 29.31 (5), b = 9.976 (10), c = 19.34 (2) A, beta = 121.07 (2) degrees. The asymmetric unit contains a half molecule of CA10 and 13.59 water molecules, the other half being related by a crystallographic twofold rotation axis. All H atoms except two water H atoms could be located from difference neutron-density maps; structure refinement converged at R = 0.635. Two of the five CH(2)-O6 groups and one of the 15 O2, O3 hydroxyl groups of CA10 are twofold orientationally disordered. A total of 13.59 water molecules in the asymmetric unit are distributed over 23 positions; 20 of which are in the CA10 cavity, and the other three occupy intermolecular interstices. Of the 123 symmetry-independent hydrogen bonds, 25 (= 20%) are three-centered and 7 (= 6%) are four-centered. Water molecules and O-H groups of CA10 form an extended network with cooperative O-H...O-H...O-H hydrogen bonds. They are arranged in 11 polygons with three, four, five, six and eight O-H bonds and in homodromic, antidromic and heterodromic arrangements. Nine polygons are located within the cavity and the others are outside.

Journal Article↗

PubMed2001

Cell cycle regulation via p53 phosphorylation by a 5'-AMP activated protein kinase activator, 5-aminoimidazole- 4-carboxamide-1-beta-D-ribofuranoside, in a human hepatocellular carcinoma cell line.

5-Aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR) is an activator of AMP activated protein kinase (AMPK) and a regulator of de novo purine synthesis. There are several earlier reports indicating that AICAR treatment suppresses cell growth via regulation of AMPK or de novo purine synthesis. We found cell growth to be suppressed by AICAR treatment in HepG2 because of p53 accumulation, which was associated with p53-Ser15 phosphorylation. Moreover, a motif very similar to the consensus motif of AMPK phosphorylation was found around p53-Ser15, and Ser15 phosphorylation was detected in AICAR treated HepG2 as was in vitro phosphorylation by AMPK. Our results suggest that AICAR may regulate cell growth via p53 phosphorylation, and also indicate the possibility of p53 phosphorylation.

AMP-Activated Protein Kinases↗

PubMed2001

Evaluation of hydration states of protein in freeze-dried amorphous sugar matrix.

A model to analyze the hydration state of protein in freeze-dried amorphous sugar matrix was proposed, based on the assumptions that there is a limit to the amount of protein that a given amount of amorphous sugar could embed and that the freeze-dried sugar-protein mixture is composed of the four components, i.e., sugars with and without hydrogen bonding to proteins and proteins with and without hydrogen bonding to sugar. Bovine serum albumin and three kinds of disaccharides, i.e., sucrose, maltose, and trehalose, were used as samples. Using the analytical equations derived from the model and experimental sugar content dependencies of the water sorption at various relative humidities, the amount of hydration water for bovine serum albumin, and the minimum amount of sugar to embed the protein were determined. On the basis of these results, the degree of interaction between the three sugars and protein was discussed, with respect to their stabilizing effect on the protein.

Carbohydrates↗

PubMed2001

Cost-effectiveness associated with the diagnosis and staging of non-small-cell lung cancer.

OBJECTIVE: We evaluated how much time and money could be saved without compromising overall results in treating lung cancer. SUBJECTS AND METHODS: We retrospectively evaluated 318 patients for T- and M-factors and 335 for N-factor. If bronchoscopy failed to diagnose a mass lesion believed to be malignant in x-ray computed tomography (CT), we proceeded to direct thoracotomy without needle or video-assisted biopsy. When mediastinal nodes were negative in CT, we proceeded to direct thoracotomy without mediastinoscopy. We searched routinely for distant metastasis with brain and abdominal CTs and bone scans. RESULTS: Lesions suspected of malignancy in CT were pathologically malignant in 93%. A total of 82.8% of patients with CT-negative mediastinum were without metastasis. The remainder, with metastasis, had a postoperative 5-year survival of 23.5%. Brain CT scans were positive in only 2.2%, abdominal CT scans in 2.4%, and bone scans in 5.0%, for patients with a cT1/T2 non-cN2 lesion. CONCLUSION: Brain and abdominal CT scans and bone scans may be omitted for cT1/T2 and non-cN2 lesions in CT. CT-negative mediastinum then leads to direct thoracotomy. The vast majority of patients may thus undergo surgery earlier with less physical and financial burden. The cost saving was calculated to be 59.4% per cT1/T2 non-cN2 patient, or US$666,815, for population evaluated based on cost-effectiveness.

Adult↗

PubMed2001

Off-pump coronary artery bypass for a heparin-allergic patient.

A 46-year-old man with no history of drug allergy developed acute myocardial infarction. Coronary angiographic findings revealed triple vessel disease. Serum hepatic enzymes were elevated due to heparin administered to control infarction, and an allergic reaction developed exclusively due to heparin. To avoid heparin use, we adopted heparin-free off-pump coronary artery bypass grafting through median sternotomy. The systemic anticoagulant agent argatroban was administered to maintain active clotting time over 200 seconds. The left internal thoracic artery was anastomosed to the left anterior descending artery, the radial artery to the diagonal branch, and the right gastroepiploic artery to the right coronary artery. Patency was confirmed by postoperative coronary angiography. No complications were noted. For patients with heparin allergy, off-pump coronary artery bypass grafting is a useful maneuver, because it can be conducted using anticoagulant agents other than heparin.

Anticoagulants↗

PubMed2001

Bone bonding behavior of the hydroxyapatite containing glass-titanium composite prepared by the Cullet method.

Bioactive composites composed of hydroxyapatite containing glass (HA-G) as a coating and titanium (Ti) or titanium alloy implants as a substrate were prepared by the Cullet method. This method results in the HA-G coating layer on the substrate with a compositional gradient in HA concentration. The results of in vitro and in vivo experiments investigating the characteristics of the composite materials are reported and discussed in this article. In vitro evaluations confirmed that the Cullet method was suitable for the preparation of the functionally gradient composite implants with higher reliable quality. In vivo experiments permitted evaluation of bonding strength of these composite implants to living bone tissue. Mechanical pull-out tests indicated that the implants bonded to living bone at least as firmly as those by the conventional method, and that the adhesion between the HA-G coating layer and metal substrate was well integrated and strongly maintained in vivo. SEM observations with EDX and a histological study of the interface between the HA-G-Ti composite implants and bone tissue revealed not only that the implants bonded to bone directly without any intervening tissue but that bone ingrowth into the HA-G layer occurred. The HA-G-Ti composite implants demonstrate both biocompatible and osteoconductive characteristics, and may be expected to obtain good and lasting results when applied clinically.

Animals↗

PubMed2001

Effects of monocular deprivation on the expression pattern of alpha-1 and beta-1 adrenergic receptors in the kitten visual cortex.

To examine how adrenergic receptors are regulated by experimental manipulation of sensory afferents, we performed immunohistochemical analysis on alpha1-, and beta1-adrenergic receptors in the brain of kittens. In normal development, these receptors were similarly expressed in both hemispheres of the occipital and frontal cortices. Notably, monocular deprivation during the sensitive period of ocular dominance plasticity significantly increased beta1-adrenergic receptor immunoreactivity in the visual cortex ipsilateral to the deprived eye. No increase in the intensity of the immunoreactivity for beta1-adrenergic receptors following monocular deprivation was found in the frontal and parietal regions of the cerebral cortex and subcortical structures, including the lateral geniculate nucleus and superior colliculus. Furthermore, such hemispheric change was not found in the alpha1-adrenergic receptor immunoreactivity following monocular deprivation. Comparisons of images, obtained by double staining for microtubule-associated protein-2 or glial fibrillary acidic protein, indicated that the increased immunoreactivity was localized on both apical dendrites of deep layer neurons and glial cells. These results indicate that the monocular deprivation during the sensitive period of ocular dominance plasticity modified beta1-adrenergic receptor immunoreactivity, including that in glial cells. Therefore, it was suggested that beta1-adrenergic receptors in the glial cells also play important roles in the regulation of ocular dominance plasticity.

Age Factors↗

PubMed2001

N-(2-Chloroethyl)-N-ethyl-2-bromobenzylamine reduces intracellular calcium response to noradrenaline in rat visual cortex.

Using the fluorescent indicator Fura-2, we investigated the effects of N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4), a noradrenergic neurotoxin, on intracellular calcium responses to noradrenaline, N-methyl-D-aspartate, and carbamylcholine chloride in brain slices of the rat visual cortex. Noradrenergic depletion in the visual cortex of young rats was induced by DSP-4, and its selectivity was confirmed by two different methods, i.e., immunostaining with anti-dopamine-beta-hydroxylase antibody and biochemical analysis by high-performance liquid chromatography. The treatment with DSP-4 (25 mg/kg i.p., x2) caused disruption of noradrenergic fibers throughout all cortical layers, and reduced the content of noradrenaline to 6.4% of that in the normal control. In the normal cortex, bath-applied noradrenaline (100 microM) increased the intracellular calcium to 123% of the control in terms of the F(340)/F(380) ratio of Fura-2 fluorescence. Quantitative analysis of the F(340)/F(380) ratio was performed in layers II to IV, since the increase was mainly observed in these layers. The intracellular calcium response to noradrenaline was significantly (P<0.0001) reduced in the DSP-4-treated animals to 63.2% of that in the normal control. The response to N-methyl-D-aspartate (100 microM) was also reduced, whereas the response to carbamylcholine chloride, a muscarinic cholinergic agonist (100 microM), was not affected by the DSP-4 treatment. From these findings we suggest that noradrenergic denervation by DSP-4 reduces the intracellular calcium response to noradrenaline through changes in the intracellular signal transduction.

Adrenergic Agents↗