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Narita M, Kuzumaki N, Narita M, Kaneko C, Tamai E, Khotib J, Miyatake M, Shindo K, Nagumo Y, Tanaka S, Suzuki T. Age-related emotionality is associated with cortical delta-opioid receptor dysfunction-dependent astrogliosis. Neuroscience 2006; 137:1359-67. [PMID: 16386853 DOI: 10.1016/j.neuroscience.2005.10.067] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Revised: 10/16/2005] [Accepted: 10/18/2005] [Indexed: 11/15/2022]
Abstract
Multiple changes occur in the aging brain, leading to age-related emotional disorders. A growing body of recent evidence suggests that the cortical delta-opioid receptor system plays a critical role in anxiety- and depressive-like behaviors in the rodent. In this study, we show that aging mice promoted anxiety-like behaviors as characterized by both the light-dark and elevated plus-maze tests, and they exhibit an increase in astrocytes in the cingulate cortex due to the dysfunction of cortical delta-opioid receptor systems. As well as aging mice, mice with a dysfunction of the delta-opioid receptor system induced by chronic treatment with the selective delta-opioid receptor antagonist naltrindole, revealed astrogliosis in the cingulate cortex, which was associated with anxiety. We also found that the microinjection of cultured astrocytes into the cingulate cortex of young mice enhanced the expression of anxiety-like behavior. Our results indicate that the aging process promotes astrogliosis in the cingulate cortex through the dysfunction of cortical delta-opioid receptors. This phenomenon may lead to emotional disorders including aggravated anxiety during normal aging.
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Imai K, Tagawa M, Matoba S, Narita M, Kanayama K. 277 FOLLICULAR GROWTH, SUBSEQUENT OVUM PICKUP, AND DOMINANT FOLLICLE REMOVAL IN COWS. Reprod Fertil Dev 2006. [DOI: 10.1071/rdv18n2ab277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The present study was designed to assess the recruitment of follicles after ovum pickup (OPU) and dominant follicle (DF) removal on the follicular wave after OPU in Holstein dry cows. Cows were reared under the same feeding and environmental conditions. In Experiment 1, follicle aspiration (>2 mm in diameter) by OPU using a 7.5-MHz linear transducer with needle (COVA needle; Misawa Medical, Tokyo, Japan) connected to an ultrasound scanner (SSD-1200; ALOKA, Tokyo, Japan) was performed in four cows. Then, ovaries were observed after OPU from Day 1 (Day 0 = the day of OPU) to Day 11 to assess the number of follicles developed. In Experiment 2, two sessions of OPU were performed with a 7 day interval between sessions, with or without dominant follicle removal, to assess the quality of developing follicles and oocytes. In the DF removal group, >8-mm follicles were aspirated at Day 5 after the first OPU session, and the same cows without DF removal were designated as a control (n = 4, crossover trial). Oocytes were evaluated by their cumulus cell morphology, cytoplasmic color, and density. To assess the developmental competence of oocytes, Grades 1 and 2 cumulus-oocyte complexes (COCs) were collected, matured, fertilized, and cultured as described by Imai et al. (2002 J. Vet. Med. Sci. 64(10), 887-891). Embryo development was assessed by the cleavage rate on Day 2 and the blastocyst formation rate on Days 7 to 9 (the day of insemination = Day 0). Data were analyzed by ANOVA or Student t-test. In Experiment 1, a dominant follicle (>8 mm in diameter) was developed during Days 3 to 5 after OPU in each donor. The mean number of developing follicles (>2 mm in diameter) were increased from Day 1 to Day 9 (Day 1: 7.5 � 2.1, Day 3: 19.0 � 1.2, Day 5: 23.3 � 9.0, Day 7: 30.3 � 11.0, Day 9: 42.0 � 15.8 and Day 11: 41.0 � 16.7 (mean � SD), P < 0.05). In Experiment 2, there was no difference in the mean number of developing follicles on the day of OPU and collected oocytes between DF removal and control groups (follicles: 47.8 � 23.0 and 39.3 � 6.2; oocytes: 27.0 � 11.6 and 26.5 � 5.4, respectively). The number of Grades 1 and 2 oocytes for the DF removal group was significantly higher (P < 0.05) than that for the control (83.6 � 1.5 and 63.2 � 14.2, respectively), and no significant difference was found within cleavage (60.0 � 37.2, 53.6 � 23.2) and blastocyst rates (34.1 � 33.9, 34.4 � 16.8). These results indicate that populations of follicles were increased till Day 9 after OPU, and the DF removal was effective at increasing oocyte quality in the developing follicles.
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Abstract
BACKGROUND Preoperative decision-making for elderly patients requires a long-term perspective. The aim of this study was to identify preoperative risk factors for decreased 1- to 5-year survival rates and to compare the survival rates of stratified risk groups with those of the sex- and age-matched general population. METHODS Subjects were 406 patients, aged 80 years or older, who underwent surgery with general anesthesia. Higher age, male sex, dependency in daily living, low serum albumin level, malignancy, abdominal surgery, emergency surgery and high ASA class were analyzed for survival using univariate and multivariate analysis with Cox's proportional hazard model. One- to 5-year survival rates were estimated using life table analysis for patients divided by risk factors. The survival data were also compared with the cumulative survival rates of the sex- and age-matched general population. RESULTS Multivariate analysis identified three factors that were significantly associated with decreased survival rates: male sex, dependency in daily living and abdominal surgery. Long-term survival among patients older than 90 years was comparable to those of the general population. Although improved in recent years, overall survival rates were much lower than expected due to poor outcome among patients dependent in daily living and those who underwent abdominal surgery. CONCLUSIONS In patients 80 years or older who underwent surgery with general anesthesia, independent risk factors for decreased survival are male sex, dependency in daily living and abdominal surgery. Only patients independent in daily living who underwent non-abdominal surgery had survival rates comparable to those of the general population.
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Alldawi L, Takahashi M, Narita M, Ayres F, Tsukada N, Osman Y, Furukawa T, Aizawa Y. Effect of prostaglandin E2, lipopolysaccharide, IFN-gamma and cytokines on the generation and function of fast-DC. Cytotherapy 2005; 7:195-202. [PMID: 16040399 DOI: 10.1080/14653240510018127] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND Recent reports have described a new strategy for differentiation and maturation of monocyte-derived DC within only 48 h of in vitro culture (fast-DC). We compared the ability of various maturation stimuli with the generation of Ag-specific T-cell responses and generation of functional fast-DC. METHODS CD14+ cells were treated with GM-CSF and IL-4 for 1 day to generate immature DC, and were then matured with either inflammatory cytokines or a combination of lipopolysaccharide (LPS) and INF-gamma. Mature DC were then used to study the effect of prostaglandin E2 (PGE2) on the stimulatory function of fast-DC. RESULTS fast-DC were CD14- and expressed mature DC surface markers, and maintained this phenotype after withdrawing the cytokine from culture. Treatment of fast-DC with a combination of LPS and INF-gamma promoted the maturation of highly uniform fast-DC. The T-cell proliferative response to DC was enhanced by inclusion of PGE2 in the MCM-mimic (TNF-a, IL-1 a, IL-6, PGE2) cocktail. DISCUSSION fast-DC are very effective; they not only reduce the labor, cost and time required for in vitro DC development, but may also represent a model more closely resembling DC differentiation from monocytes in vivo.
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Narita M, Akai H, Kita T, Nagumo Y, Narita M, Sunagawa N, Hara C, Hasebe K, Nagase H, Suzuki T. Involvement of mitogen-stimulated p70-S6 kinase in the development of sensitization to the methamphetamine-induced rewarding effect in rats. Neuroscience 2005; 132:553-60. [PMID: 15837117 DOI: 10.1016/j.neuroscience.2004.12.050] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2004] [Indexed: 10/25/2022]
Abstract
The neural plasticity associated with behavioral sensitization following repeated administration of a psychostimulant methamphetamine (METH) is thought to require synthesis of new proteins. The aim of the present study was to investigate the role of p70-S6 kinase (p70-S6K) phosphorylation, which contributes to the selective translation of a unique family of mRNA, in mediating both the METH-induced rewarding effect and its sensitization. An intra-nucleus accumbens (N.Acc.) pre-injection with 0.025 pmol/rat of a selective p70-S6K inhibitor rapamycin failed to affect the METH-induced conditioned place preference. However, this treatment clearly abolished the development of sensitization of the METH-induced conditioned place preference. Consistent with the behavioral assay, the level of the immunoreactivity of phosporylated-p70-S6K was not changed in the cytosolic fraction of the N.Acc. obtained from rats that had revealed the METH-induced rewarding effect. In contrast, the immunoreactivities in the cytosolic preparation for Western blotting and immunohistochemical density of phosphorylated-p70-S6K were significantly increased in the N.Acc. obtained from METH-sensitized rats as compared with those with chronic saline treatment. However, the immunoreactivities of phosphorylated-extracellular signal-regulated kinase and phosphorylated-ribosomal S6 protein were not significantly altered in the N.Acc. under the same condition. The present data provide evidence for the change in the translation rate, which can be regulated by S6K phosphorylation, in the N.Acc. during the development of sensitization to METH-induced rewarding effects in rats.
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Narita M, Ishii M. Encephalomalacic lesions in pigs dually infected with porcine reproductive and respiratory syndrome virus and pseudorabies virus. J Comp Pathol 2005; 131:277-84. [PMID: 15511536 PMCID: PMC7127378 DOI: 10.1016/j.jcpa.2004.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2003] [Accepted: 05/04/2004] [Indexed: 11/28/2022]
Abstract
Four pigs (group 1) were infected with an aerosol containing porcine reproductive and respiratory syndrome virus (PRRSV) followed 7 days later by pseudorabies virus (PRV). Three further pigs (group 2) received PRRSV alone, two (group 3) received PRV alone, and two (group 4) remained as uninfected controls. Despite the admittedly small numbers of animals, the experiment appeared to throw light on aspects of synergy. Thus, the group 1 pigs showed severe neurological signs characterized by ataxia and muscular tremors. Total cell numbers in the bronchoalveolar lavage fluid were increased in all PRRSV-infected pigs, and PRRSV antigen was detected in the alveolar macrophages. Total cell numbers in the cerebrospinal fluid of group 1 pigs were considerably greater than those demonstrated in group 3, but no PRV antigen was found. Pigs of groups 1 and 2 showed pulmonary lesions, characterized by interstitial pneumonia and PRRSV antigen immunolabelling. Non-suppurative encephalitis was found in five of the six pigs of groups 1 and 3. In particular, one group 1 animal had severe necrotizing encephalitis with intranuclear inclusion bodies and associated immunolabelling of PRV antigen. The other three group 1 pigs had prominent malacic lesions, with macrophages. These neuropathological findings strongly suggested that PRRSV infection in pigs enhances the severity of brain lesions caused PRV.
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Akasawa A, Narita M, Ohya Y. Thirty years generation gap dramatically increased prevalence of asthma and the other allergic diseases in Japan. J Allergy Clin Immunol 2005. [DOI: 10.1016/j.jaci.2004.12.289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Narita M, Goda S, Inaba Y, Imai K, Matoba S, Tagawa M, Nagai T, Saito N, Yonai M, Dochi O. 289 EFFECTS OF THE STORAGE OF BOVINE OVARIES ON THE NUCLEAR MATURATION AND DEVELOPMENT OF IN VITRO PRODUCED EMBRYOS. Reprod Fertil Dev 2005. [DOI: 10.1071/rdv17n2ab289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The objectives of this study were to investigate effects of storage of bovine ovaries on the maturation of oocytes and to determine the optimal maturation time for oocytes obtained from the stored ovaries. Ovaries were obtained at a local abattoir and transported in physiological saline to the laboratory (18°C, 3 h; storage group). As a control, oocytes were collected from ovaries without storage. Other ovaries were kept in a plastic bag without solution (Bag-group) or with saline (Saline-group). These ovaries were preserved at 20°C for 18 h. Then cumulus-oocyte complexes were collected and maturated in TCM-199 + 5% CS. In Experiment 1, to investigate effects of the storage methods of bovine ovaries on the timing of germinal vesicle breakdown (GVBD) and the progression to MII in oocytes obtained from ovaries, oocytes were fixed every 2 h (0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 h) from the start of in vitro maturation, and then stained for examination of their nuclear stage. In Experiment 2, to investigate effects of length of in vitro maturation (18, 20, 22, 24 h) of oocytes (18-h, 20-h, 22-h and 24-h group, respectively) obtained from the ovaries stored in a saline for 18 h at 20°C on the subsequent in vitro development after IVF and IVC. Following insemination, the presumptive zygotes were cultured in CR1aa + 5% CS for 6 days to assess the development of embryos on Day 2 (Day 0 = the day of IVF) for rates of cleavage and on Day 6 for rates of embryo development to morulae (M), compacted morulae (CM), and blastocyst (BL) stages. The data of nuclear stage were analyzed by ANOVA after transformation to arcsine, and the rates of embryo development were analyzed by chi-square. There were two peaks of GVBD in the storage group, one occurred at 2 h of maturation culture, the other at 4–8 h of culture as control. There were between-treatment differences in the timing of increase in the rates of oocytes to reach MII. After 12 h of culture 21.2 ± 1.1% of oocytes in the Saline-group and 11.6 ± 4.6% of oocytes in the Bag-group reached MII, but no oocytes in the control group reached MII (P < 0.05). Furthermore, the rate of oocytes in the Saline-group matured to MII at 20 h of culture was lower than that of the control group (Bag-group: 67.9 ± 7.3%; Saline-group: 61.2 ± 14.5%; control: 82.9 ± 5.3%) (P < 0.05). The rates of embryos that cleaved after IVF of IVM oocytes in the 18-h group (90.2 ± 7.0%) was higher than those of the other groups (20-h group: 81.3 ± 8.2%, 22-h group: 80.5 ± 13.2%, 24-h group: 75.8 ± 6.0%) (P < 0.05). The rate of embryos developed to M, CM, and BL stages in the 18-h group (48.4 ± 6.7%) was the highest among the treatments, and significantly higher than that of the 24-h group (36.2 ± 6.7%) (P < 0.05). These results indicated that the timing of undergoing GVBD and reaching MII of oocytes obtained from the stored ovaries was earlier than that of oocytes obtained from the non-preserved ovaries, and the optimal maturation time for oocytes obtained from stored ovaries was 18 h.
This work was supported by The Ito Foundation, Tokyo, Japan.
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Shimizu K, Murata T, Hiramoto K, Narita M, Inui M, Tagawa T. Calmodulin-dependent phosphodiesterase (PDE) 1 in human oral melanoma cell lines. Int J Oral Maxillofac Surg 2005. [DOI: 10.1016/s0901-5027(05)80873-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Imai K, Tagawa M, Matoba S, Narita M, Saito N. 246 FOLLICULAR DEVELOPMENT AND OOCYTE QUALITY AFTER OVUM PICKUP IN DONOR COWS. Reprod Fertil Dev 2005. [DOI: 10.1071/rdv17n2ab246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The present study was designed to assess the renewal of follicular development and oocyte quality after ovum pickup (OPU) in Holstein dry cows. Cows were kept under the same feeding and environmental conditions. In Experiment 1, follicle aspiration (more than 2 mm) by OPU using a 7.5 MHz linear transducer with needle (cova needle, Misawa Medical, Tokyo, Japan) connected to an ultrasound scanner (SSD-1200, ALOKA, Tokyo, Japan) was performed in four cows. After OPU ovaries were observed from Day 4 (Day 0 = the day of OPU) to Day 11 to assess the number of follicles that developed. In Experiment 2, two sessions of OPU (n = 11) were performed with a 7-day interval between to assess the quality of developing follicles and oocytes. Oocytes were evaluated by their cumulus cell morphology, cytoplasmic color, and density. To assess the developmental competence of oocytes, collected cumulus-oocyte complexes (COCs) were cultured for 20 h in TCM-199 supplemented with 5% calf serum (CS) in a microdroplet (volume was adjusted to 5 μL/oocyte) at 38.5°C under atmosphere of 5% CO2 in air. After maturation, the COCs were inseminated with frozen-thawed semen collected from the same ejaculation of a single bull. The fertilization was performed with BO solution as described by Imai et al. (2002 J. Vet. Med. Sci. 64(10), 887–891). The putative zygotes were then cultured in CR1aa supplemented with 5% CS under the same conditions as maturation culture for nine days. Embryo development was assessed by the cleavage rate on Day 2 and the blastocyst formation rate on Days 7 to 9 (the day of insemination = Day 0). Data were analyzed by ANOVA or Student's t-test. In Experiment 1, the mean number of developing follicles (larger than 2 mm in diameter) were increased from Day 4 to Day 11 (Day 4: 19.8 ± 10.0, Day 7: 32.5 ± 9.5; Day 11: 39.5 ± 10.7 (mean ± SD), respectively, P < 0.05). In Experiment 2, the mean number of developing follicles and collected oocytes on the day of OPU were significantly (P < 0.05) different between the first and second sessions (54.2 ± 12.4 and 40.8 ± 12.7, 45.7 ± 20.2 and 27.7 ± 8.7, respectively). The percentage of Grade 1 and 2 oocytes for the first session was significantly lower (P < 0.05) than those for the second session (59.1 ± 8.4 and 69.0 ± 11.8), and no significant differences were found within cleavage and blastocyst rates. The mean numbers of blastocysts obtained per session were 14.2 ± 8.9 and 9.7 ± 6.3 in the first and second sessions, respectively. These results indicate that populations of follicles were increased till Day 11 after OPU, and proportion of normal oocytes were increased in the renewal follicles.
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Shiraishi M, Kamo T, Nemoto S, Narita M, Kamegai M, Baevsky RM, Funtova II. Blood pressure variability during 120-day head-down bed rest in humans. Biomed Pharmacother 2004; 57 Suppl 1:35s-38s. [PMID: 14572675 DOI: 10.1016/j.biopha.2003.08.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Influence of physical inactivity and microgravity to periodic structure of blood pressure was studied. Six healthy males were kept under head-down bed rest (HDBR) for 120 days. Blood pressure and heart rate (HR) were recorded by a portable sphygmomanometer and a Holter electrocardiogram, respectively. The results were analyzed by spectrum analysis. Phase, amplitude and acrophase of systolic blood pressure (SBP) by approximately 24, 12 and 8 h were measured before, 60, 120 day and after HDBR. The phase at 24, 12 and 8 h did not show significant changes during HDBR, and acrophase showed a tendency to shift to 14:00 after HDBR. Amplitude for 24 h tended to attenuate during bed rest (BR), and significantly increased after BR. The results of this study suggest that the circadian rhythm of SBP and HR were maintained by strict control of sleep, awakening and food intake in microgravity model of a long-term BR state. However, the tendency to decrease 24-h cyclic amplitude of SBP appeared to be the rhythmic modulation related to cardiovascular deconditioning.
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Narita M, Matsumura Y, Ozaki S, Ise Y, Yajima Y, Suzuki T. Role of the calcium/calmodulin-dependent protein kinase ii (CaMKII) in the morphine-induced pharmacological effects in the mouse. Neuroscience 2004; 126:415-21. [PMID: 15207359 DOI: 10.1016/j.neuroscience.2004.03.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2004] [Indexed: 11/20/2022]
Abstract
Calcium/calmodulin-dependent protein kinase II (CaMKII) is a family of multifunctional protein kinases that activates signaling pathways. The present study was designed to ascertain whether CaMKII could play a substantial role in the expression of morphine-induced antinociception, hyperlocomotion and rewarding effect in the mouse. An i.c.v. pretreatment with a CaMKII inhibitor KN-93 failed to affect the antinociception and hyperlocomotion induced by s.c. administration of a prototype micro-opioid receptor agonist morphine. In contrast, the morphine-induced place preference was significantly attenuated by i.c.v. pretreatment with KN-93. The levels of phosphorylated-CaMKII (p-CaMKII) in the limbic forebrain, but not in the frontal cortex and the lower midbrain, were significantly increased in morphine-conditioned mice, whereas the levels of CaMKII in three brain regions obtained from morphine-conditioned mice were not changed. This up-regulation of p-CaMKII in the limbic forebrain obtained from morphine-conditioned mice was significantly inhibited by i.c.v. pretreatment with KN-93. These results provide evidence that the increase in CaMKII activity in the mouse limbic forebrain may contribute to the rewarding effect, but not the antinociception and the hyperlocomotion, induced by morphine.
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Narita M, Akai H, Nagumo Y, Sunagawa N, Hasebe K, Nagase H, Kita T, Hara C, Suzuki T. Implications of protein kinase C in the nucleus accumbens in the development of sensitization to methamphetamine in rats. Neuroscience 2004; 127:941-8. [PMID: 15312906 DOI: 10.1016/j.neuroscience.2004.06.017] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2004] [Indexed: 11/21/2022]
Abstract
Repeated treatment with methamphetamine leads to an enhancement in the methamphetamine-induced dopamine release and its related behaviors. This phenomenon is called sensitization or reverse tolerance. Protein kinase C (PKC) controls numerous signaling cascades by virtue of its ability to phosphorylate target proteins that include other kinases. The purpose of study was then to investigate the implication of PKC in the development of sensitization to the rewarding effect and to the extracellular dopamine release induced by methamphetamine in rats. The conditioned place preference paradigm and in vivo microdialysis assay were performed in the present study. An intra-nucleus accumbens injection of a selective PKC inhibitor chelerythrine chloride abolished the enhancement of the methamphetamine-induced place preference following repeated treatment with methamphetamine. Furthermore, intra-nucleus accumbens injection of chelerythrine chloride blocked the development of sensitization to dopamine release and to the decrease in the major dopamine metabolites, 3'4-dihydroxyphenylacetic acid and homovanillic acid, in the nucleus accumbens induced by repeated methamphetamine treatment. Under these conditions, the immunoreactivity of the cytosolic phosphorylated conventional- or classic-type PKC in the limbic forebrain region including the nucleus accumbens was slightly, but significantly increased in methamphetamine-sensitized rats. The present data provide evidence for the implication of PKC in the nucleus accumbens in the development of sensitization to the methamphetamine-induced rewarding effect, dopamine release and inhibition of dopamine metabolism/re-uptake in rats.
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Goda S, Narita M, Miyamura M, Hamano S, Dochi O, Koyama H. 97EFFECT OF RAPID TEMPERATURE CHANGE ON VIABILITY OF FROZEN-THAWED
IVM/IVF BOVINE EMBRYOS. Reprod Fertil Dev 2004. [DOI: 10.1071/rdv16n1ab97] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In on-farm conditions, frozen bovine embryos are frequently thawed at various environmental temperatures. Thawing temperature is an important factor affecting the viability of frozen-thawed bovine embryos. The present study investigated the effects of rapid temperature change on the viability of frozen IVM/IVF bovine embryos after thawing. Day 7- and 8- (Day 0=day of insemination) expanded blastocysts were used in this study. Embryos were produced as previously described by Hamano & Kuwayama (1993 Theriogenology 39, 703–712,). Embryos were frozen in TCM-199 supplemented with 1.4M glycerol, 20% calf serum (CS), and 0.25-M sucrose. The embryos were loaded into 0.25mL straws. After equilibration, the straws were placed directly into a precooled alcohol chamber of a freezer at −6°C, seeded 1min later, held at −6°C for 10min, cooled to −25°C at a rate of 0.33°C/min, and then plunged into liquid nitrogen. Embryos were thawed by holding the straws in room temperature air for 10s, and then immersing them in a 35°C water bath for 10s. The thawed straws were randomly assigned to one of two groups. Some thawed straws were held for 5min at −15, −5, 0, 5, or 15°C, and were then transferred directly into a water bath at 35°C for 5min (Group 1). The remaining straws were subjected to the same post-thaw cooling step procedures as Group 1 two times (Group 2). The embryos were then directly rehydrated in PBS supplemented with 5% CS at 35°C, and cultured in TCM-199 supplemented with 5% CS and 0.1mM β-mercaptoethanol. The morphology and hatching of embryos was assessed 72h later. Data were analyzed using the chi-square method and Fisher’s exact test. The results are presented in the Table. There were no significant differences in the hatching rate among 5 temperatures in Group 1. Although there were no differences in the hatching rate of embryos held at −5, 0, 5, or 15°C after thawing, the rate for embryos held at −15°C was significantly lower than those of the other treatments in Group 2 (P<0.05). The straws held at −15°C twice (Group 2), showed refreezing. These results suggest that exposing thawed straws to a broad range of environmental temperatures (−5 to 15°C) had no effect on the viability of frozen-thawed IVM/IVF bovine embryos. However, embryos might be irreversibly damaged when held at −15°C.
Table 1
Effect of rapid temperature change on the viability of frozen-thawed IVM/IVF bovine embryos
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Narita M, Kei I, Dochi O. 321EFFECTS OF BUTYROLACTONE-I AND CYCLOHEXIMIDE ON GERMINAL VESICLE
BREAKDOWN IN BOVINE OOCYTES AND SUBSEQUENT IN VITRO DEVELOPMENT AFTER
IVM-IVF-IVC. Reprod Fertil Dev 2004. [DOI: 10.1071/rdv16n1ab321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The present study aimed to compare the effects of butyrolactone-I (BL-I) and cycloheximide (CHX) on inhibition of germinal vesicle (GV) breakdown (GVDB) in bovine oocytes and subsequent in vitro development after in vitro maturation and fertilization. Furthermore, in experiment 2, we compared the kind of supplemented protein with CHX during inhibition of GVBD of oocytes obtained from ovaries stored for 1 day, and examined time extension of storage of oocytes. In experiment 1, bovine cumulus-oocyte complexes (COCs) collected by the aspiration of 3- to 5-mm follicles of ovaries from at a local abattoir were preincubated for 24h in TCM-199 supplemented with 100μM BL-I and 3mgmL−1 BSA or 100μLmL−1 CHX and 5% CS. As a control, fresh COCs were used without preincubation. In experiment 2, the COCs were collected from ovaries stored in phygiological saline for 1 day at 20°C. The collected COCs were preincubated for 24h in TCM-199 supplemented with 100μLmL−1 CHX and 3mgmL−1 BSA or 5% CS (CHX+BSA, CHX+CS). As a control, fresh COCs collected from ovaries stored in the same condition were used without preincubation. In both experiments, the COCs were maturated and inseminated with frozen-thawed spermatozoa. After preincubation, maturation and fertilization, some oocytes or zygotes were fixed to assess the rates of oocytes at the GV stage, MII or sperm penetration. Following insemination, the presumptive zygotes were cultured in CR1aa (Rosenkrans, C.F. Jr. et al., 1993 Biol. Reprod. 49, 459–462) supplemented with 5% CS for 8 days. Embryo development was evaluated for cleavage rates on Day 2, and for blastocyst rates on Days 7 and 8 (IVF=Day 0), respectively. To evaluate embryo quality, the total cell numbers in the blastocysts were counted by means of the air-drying method. Three replicates were carried out for each experiment. Data were analyzed by chi-square test (cleavage and blastocyst rates) and ANOVA (cell numbers). In experiment 1, there were no differences in the rates of the oocytes at the GV stage between BL-I (71.4±10.7%, mean±SD) and CHX (86.7±10.9%), but the rates of the oocytes at the MII stage for BL-I (59.6±7.4%) tended to be lower than for those in CHX (80.0±14.1%, P<0.1). The rate of MII stage for control was 67.5±18.4%, and there were no differences between control and other treatments. No differences were found in sperm penetration, normal fertilization and polyspermy after in vitro fertilization. The cleavage rate for oocytes in CHX (81.0±1.2%) was significantly higher than for those in BL-I (65.0±13.1%, P<0.01), and there was a tendency for the cleavage rate in BL-I to be lower than that of the control (75.5±4.7%, P<0.1). A significantly lower percentage of embryos cultured in BL-I (19.2±13.8%) developed to the blastocyst stage than those of embryos in the control (32.0±11.2%, P<0.05), but there were no differences in the blastocyst rate between BL-I and CHX (25.9±8.8%). Cell numbers in the blastocysts in BL-I (177.2±15.9, n=21) and CHX (191.2±12.9, n=31) were not significantly different compared to the control (198.4±14.3, n=34). In experiment 2, no significant differences were found in the cleavage rates (CHX+CS, 64.0±18.7%; CHX+BSA, 68.1±10.8% and control, 72.2±8.3%). However, the blastocyst rates in CHX+CS (4.0±7.8%) and CHX+BSA (7.7±9.2%) were significantly lower than the control (20.4±3.7%, P<0.05). These results suggested that CHX can reversibly inhibit the GVBD of bovine oocytes for 24h without compromising subsequent developmental competence after in vitro maturation, fertilization, and culture. However, COCs collected from stored ovaries for 1 day and preincubated with CHX failed to develop into blastocysts regardless of the kind of supplemented protein.
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Narita M, Imai S, Narita M, Kasukawa A, Yajima Y, Suzuki T. Increased level of neuronal phosphoinositide 3-kinase γ by the activation of μ-opioid receptor in the mouse periaqueductal gray matter: further evidence for the implication in morphine-induced antinociception. Neuroscience 2004; 124:515-21. [PMID: 14980723 DOI: 10.1016/j.neuroscience.2003.11.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2003] [Indexed: 10/26/2022]
Abstract
It has been proposed that phosphoinositide 3-kinase (PI3K), one of the phosphatidylinositol kinases, can be regulated by G-protein-coupled receptor as well as nerve growth factor-associated receptors. The aim of the present study was to investigate whether in vivo treatment with morphine, a mu-opioid receptor (MOR) agonist, could directly regulate PI3Kgamma isoform in the mouse periaqueductal gray matter (PAG). Using the polyclonal antibody recognizing a p110gamma catalytic subunit of PI3Kgamma, PI3Kgamma-like immunoreactivity (IR) was mostly seen in the membrane of the cell labeled by anti-neuron-specific nuclear protein. A single s.c. injection of morphine caused a marked increase in the number of PI3Kgamma-IR expressing cells in the PAG. Double immunolabeling assay showed that MOR-IR was mostly overlapped with PI3Kgamma-IR on the cell surface in the PAG section. Additionally, phosphorylated-phospholipase Cgamma1 (PLCgamma1-IR) was highly detected in the membrane compartment of the increased PI3Kgamma-IR-positive cells of this region. Further pharmacological evidence for the critical role of PI3Kgamma in MOR-mediated antinociceptive response was provided by the warm-plate test. The dose-response lines for antinociceptive effects of morphine were significantly shifted to the right following i.c.v. treatment with PI3K inhibitors. These findings suggested that acute treatment with morphine may directly activate the PI3Kgamma/PLCgamma1 pathway in the PAG. This effect may, at least in part, result in the expression of morphine-induced pharmacological actions including antinociception in mice.
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Narita M, Oe K, Kato H, Shibasaki M, Narita M, Yajima Y, Yamazaki M, Suzuki T. Implication of spinal protein kinase C in the suppression of morphine-induced rewarding effect under a neuropathic pain-like state in mice. Neuroscience 2004; 125:545-51. [PMID: 15099668 DOI: 10.1016/j.neuroscience.2004.02.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2004] [Indexed: 10/26/2022]
Abstract
We previously demonstrated that spinal protein kinase C (PKC) is involved in the development of a neuropathic pain-like state induced by sciatic nerve ligation, and the morphine-induced rewarding effect is attenuated by sciatic nerve ligation in rodents. Here we first investigated whether sciatic nerve injury could change the activity of a conventional PKC (cPKC) and an atypical PKC isoform PKCzeta in the mouse spinal cord. The second experiment was to investigate whether direct inhibition of spinal PKC by intrathecal (i.t.) administration of a specific PKC inhibitor, 2-[8-[(dimethylamino)methyl]-6,7,8,9-tetrahydropyrido[1,2-a]indol-3-yl]-3-(1-methyl-1H-indole-3-yl)maleimide (RO-32-0432), could affect the rewarding effect induced by morphine following sciatic nerve ligation in mice. We found here that the activities of both cPKC and PKCzeta in the spinal cord were clearly increased following sciatic nerve ligation. Furthermore, i.t. administration of RO-32-0432 reversed a long-lasting pain-like syndrome as indicated by thermal hyperalgesia following sciatic nerve ligation in mice. These data provide direct evidence that activated cPKC and PKCzeta in the spinal cord may contribute to the development and maintenance of neuropathic pain. In the present study, we confirmed that the morphine-induced place preference was significantly suppressed by sciatic nerve ligation. It should be mentioned that i.t. pretreatment with RO-32-0432 significantly reversed the attenuation of morphine-induced rewarding effect following sciatic nerve ligation. These results suggest that activation of PKCs, including cPKC and PKCzeta, within the spinal cord is directly responsible for the attenuation of the morphine-induced rewarding effect under a neuropathic pain-like state following sciatic nerve ligation in mice.
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Matoba S, Imai K, Mimaki Y, Narita M, Tagawa M, Dochi O, Saito N. 107TOXICITY OF ETHYLENE GLYCOL ON FROZEN AND THAWED IVP EMBRYOS IN DIRECT
TRANSFER METHOD. Reprod Fertil Dev 2004. [DOI: 10.1071/rdv16n1ab107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Ethylene glycol (EG) is a cryoprotectant which is highly permeable to mammalian embryos. But the toxicity of this cryoprotectant for embryos after thawing has not been investigated. The aim of this study was to determine the toxicity of EG to embryos frozen and thawed by a direct transfer method. In vitro-produced Day 7 blastocysts (n=529) of grade 1 quality were used in this study. Embryos were frozen in 1.5MEG in Dulbecco’s PBS (DPBS) supplemented with 0.1M sucrose, 4mgmL−1 BSA and 20% fetal calf serum (FCS). Embryos were transferred into freezing medium, loaded into 0.25-mL straws and kept for more than 15min for equilibration; then the straws were plunged into a −7°C methanol bath of a programmable freezer for 1min, seeded at −7°C, held at −7°C for 14min, cooled to −30°C at the rate of −0.3°Cmin−1 and then plunged into liquid nitrogen. The straws were thawed by holding in air for 6sec, and then placed in water at 30°C for 15s. After thawing, the straws were held for 0, 10, 20, 30 and 60min (holding time) at either 38.5 or 26.0°C. Ethylene glycol was removed from the embryos by placing them into DPBS supplemented with 20% CS at 38.5°C more than 20min. The embryos were cultured in TCM-199 supplemented with 20% FCS and 0.1mM β-mercaptoethanol under a gas phase of 5% CO2 in air at 38.5°C for 72h. Viability of embryos was evaluated at 0-, 24-, 48- and 72-h incubation by their morphological development. Data were analyzed by ANOVA. There was no significantly difference in the survival rate of thawed embryos held at 38.5°C or 26.0°C for the same holding periods. The survival rate of the thawed embryos held at 38.5°C decreased significantly when the holding period exceeded 30min compared with no holding period after 24- and 72-h culture (P<0.05, respectively). On the other hand, the survival rate of the thawed embryos held at 26.0°C decreased significantly when the holding time was 60min compared with less than 20min of holding after 24-h culture, and less than 10min after 72-h culture (P<0.05, respectively). Therefore, toxicity of EG was observed when thawed embryos were held for 30 and 60min at 38.5°C and 60min at 26.0°C. These results suggest the toxicity of EG in direct transfer methods can be avoided by transferring the embryos within 20min after thawing.
Table 1
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Nakagawa T, Sugiyama T, Shimizu K, Murata T, Narita M, Nakamura S, Tagawa T. Characterization of the development of ectopic chondroid/bone matrix and chondrogenic/osteogenic cells during osteoinduction by rhBMP-2: a histochemical and ultrastructural study. Oral Dis 2003; 9:255-63. [PMID: 14628893 DOI: 10.1034/j.1601-0825.2003.02912.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To investigate the characteristics of ectopic chondroid/bone matrix and chondrogenic/osteogenic cells induced by recombinant human bone morphogenetic protein-2 (rhBMP-2). MATERIALS AND METHODS rhBMP-2 (5 microg) combined with atelocollagen was implanted into calf muscles of rats and removed on days 7, 10, 14, 21, or 28. Tissue sections were examined using: (i) hematoxylin/Alcian blue/Sirius red stain, (ii) enzyme histochemistry for alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase activity, (iii) immunohistochemistry for types I, II, and X collagen, and (iv) electron microscopy. RESULTS On day 7, numerous fibroblast-like cells with ALP activity were present on the pellet rim. On day 10, chondroid matrix (CM) had formed, contained both type I collagen and proteoglycans, and often continued into the BMP pellet. On day 14, bone-like matrix formed around hypertrophic chondrocytes simultaneously with endochondral ossification. Coexpression of types I and II collagen within chondrocytes and osteocytes was observed throughout the time course of the experiment. CONCLUSION These results suggest that fibroblast-like cells invading the pellet differentiate into chondrocytes and form CM under the scaffold of the carrier component. It appears that some chondrocytes change their phenotype to produce the bone-like matrix and remain within the endochondral bone. This process enables rapid osteogenesis to occur.
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Yamanaka R, Abe T, Yajima N, Tsuchiya N, Homma J, Kobayashi T, Narita M, Takahashi M, Tanaka R. Vaccination of recurrent glioma patients with tumour lysate-pulsed dendritic cells elicits immune responses: results of a clinical phase I/II trial. Br J Cancer 2003; 89:1172-9. [PMID: 14520441 PMCID: PMC2394324 DOI: 10.1038/sj.bjc.6601268] [Citation(s) in RCA: 212] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
In this Phase I/II trial, the patient's peripheral blood dendritic cells were pulsed with an autologous tumour lysate of the glioma. Seven patients with glioblastoma and three patients with anaplastic glioma, ranging in age from 20 to 69 years, participated in this study. The mean numbers of vaccinations of tumour lysate-pulsed dendritic cells were 3.7 times intradermally close to a cervical lymph node, and 3.2 times intratumorally via an Ommaya reservoir. The percentage of CD56-positive cells in the peripheral blood lymphocytes increased after immunisation. There were two minor responses and four no-change cases evaluated by radiological findings. Dendritic cell vaccination elicited T-cell-mediated antitumour activity, as evaluated by the ELISPOT assay after vaccination in two of five tested patients. Three patients showed delayed-type hypersensitivity reactivity to the autologous tumour lysate, two of these had a minor clinical response, and two had an increased ELISPOT result. Intratumoral CD4+ and CD8+ T-cell infiltration was detected in two patients who underwent reoperation after vaccination. This study demonstrated the safety and antitumour effects of autologous tumour lysate-pulsed dendritic cell therapy for patients with malignant glioma.
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Osman Y, Narita M, Ayres F, Takahashi M, Alldawi L, Tatsuo F, Toba K, Hirohashi T, Aizawa Y. Generation of Ag-specific cytotoxic T lymphocytes by DC transfected with in vitro transcribed influenza virus matrix protein (M1) mRNA. Cytotherapy 2003; 5:161-8. [PMID: 12745578 DOI: 10.1080/14653240310001064] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Application of DC transfected with tumor Ag RNA is promising for DC-based tumor immunotherapy. In this study, Ag-specific cytotoxic T lymphocytes (CTL) were generated by priming lymphocytes with DC transfected with in vitro transcribed (IVT) influenza virus matrix protein M1 (M1) mRNA. METHODS Human UC blood-CD34+ cell-derived DC were transfected with IVT mRNA encoding either the enhanced green fluorescence protein (EGFP), or M1 by square-wave electroporation. DC were confirmed to have typical morphology and phenotype. DC transfected with IVT EGFP mRNA were analyzed with the FACScan flow cytometer, to confirm the efficiency of this transfection method. On Days 7, 14, 21 and 28 after the start of DC culture, DC were harvested and electroporated with M1 mRNA. The transfected DC were co-cultured with autologous UC blood CD34- cells. One week after the fourth priming of autologous CD34 negative cells with M1 mRNA electroporated DC, Ag-specific CTL activity was evaluated. To prepare target cells, M1 mRNA was added to autologous DC 48 h prior to CTL assays. RESULTS Our CTL assays results indicate that UC blood CD34+ cell-derived DC transfected with M1 mRNA by electroporation stimulated Ag-specific CTL responses that are capable of recognizing and lysing autologous DC loaded with M1 mRNA. M1 mRNA transfected DC-primed CTL showed a significant cytotoxic activity against M1 mRNA loaded autologous DC, while nearly baseline cytotoxic activity was recorded for the M1 mRNA unloaded DC. DISCUSSION Our results showed that mRNA-transfected DC are potent stimulators of T-cell immunity in vitro. In addition, mRNA-loaded DC can function as targets in CTL cytotoxicity assays, which offer a practical substitute for tumor cells in assays to test the immunological effects of specific Ags.
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Narita M. Erratum to “Diversity of mercury resistance determinants among Bacillus strains isolated from sediment of Minamata Bay” [FEMS Microbiol. Lett. 233 (2003) 73–82]. FEMS Microbiol Lett 2003. [DOI: 10.1016/s0378-1097(03)00586-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Narita M, Aoki K, Takagi M, Yajima Y, Suzuki T. Implication of brain-derived neurotrophic factor in the release of dopamine and dopamine-related behaviors induced by methamphetamine. Neuroscience 2003; 119:767-75. [PMID: 12809697 DOI: 10.1016/s0306-4522(03)00099-x] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
It is widely recognized that methamphetamine enhances the release of dopamine at dopaminergic neuron terminals of the mesolimbic system, which induces dopamine-related behaviors. Brain-derived neurotrophic factor (BDNF), a neurotrophin, binds to and activates its specific receptor tyrosine kinase, TrkB. BDNF has been shown to influence the release of dopamine in the mesolimbic dopamine system. The present study was designed to investigate roles of BDNF and TrkB in the expression of methamphetamine-induced dopamine release in the nucleus accumbens and dopamine-related behaviors induced by methamphetamine in rats. Methamphetamine (1 mg/kg, s.c.) produced a substantial increase in the extracellular levels of dopamine and induced a progressive augmentation of dopamine-related behaviors such as rearing and sniffing. In contrast, both the stimulation of dopamine release and induction of dopamine-related behaviors by methamphetamine were significantly suppressed by pretreatment with intra-nucleus accumbens injection of either BDNF (2.0 microl/rat, 1:1000, 1:300 and 1:100) or TrkB (2.0 microl/rat, 1:1000 and 1:100) antibody. Furthermore, the basal level of dopamine in the nucleus accumbens was not affected by treatment with both BDNF and TrkB antibodies. These findings provide further evidence that BDNF/TrkB pathway is implicated in the methamphetamine-induced release of dopamine and the induction of dopamine-related behaviors.
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Endo G, Yamagata T, Narita M, Huang CC. Bioluminescence Biosensor for the Detection of Organomercury Contamination. ACTA ACUST UNITED AC 2003. [DOI: 10.1002/abio.200390018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ozaki S, Narita M, Narita M, Iino M, Miyoshi K, Suzuki T. Suppression of the morphine-induced rewarding effect and G-protein activation in the lower midbrain following nerve injury in the mouse: involvement of G-protein-coupled receptor kinase 2. Neuroscience 2003; 116:89-97. [PMID: 12535942 DOI: 10.1016/s0306-4522(02)00699-1] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The present study was designed to investigate whether a state of neuropathic pain induced by sciatic nerve ligation could alter the rewarding effect, antinociception, and G-protein activation induced by a prototype of mu-opioid receptor agonist morphine in the mouse. The sciatic nerve ligation caused a long-lasting and profound thermal hyperalgesia. Under this neuropathic pain-like state, an i.c.v. morphine-induced place preference was observed in sham-operated mice but not in sciatic nerve-ligated mice. However, no differences in the antinociceptive effect of i.c.v.-administered morphine were noted between the groups. The increases in the binding of guanosine-5'-o-(3-[(35)S]thio)triphosphate induced by morphine in lower midbrain membranes including the ventral tegmental area, which contributes to the expression of the rewarding effect of opioid, were significantly attenuated in sciatic nerve-ligated mice. On the other hand, there were no differences in the stimulation of guanosine-5'-o-(3-[(35)S]thio)triphosphate binding to pons/medulla membranes, which plays an important role in the antinociception of mu-opioid receptor agonists, between the groups. In addition, no changes in levels of guanosine-5'-o-(3-[(35)S]thio)triphosphate binding by either the selective delta- or kappa-opioid receptor agonists were noted in membrane of the lower midbrain and limbic forebrain membranes obtained from sciatic nerve-ligated mice. Reverse transcription-polymerase chain reaction analysis showed that sciatic nerve ligation did not alter the mRNA product of mu-opioid receptors in the lower midbrain, indicating that a decrease in some mu-opioid receptor functions may result from the uncoupling of mu-opioid receptors from G-proteins. We found a significant increase in protein levels of G-protein-coupled receptor kinase 2, which causes receptor phosphorylation in membranes of the lower midbrain but not in the pons/medulla, obtained from mice with nerve injury, whereas there were no changes in the protein level of phosphorylated-protein kinase C in the lower midbrain. These results suggest that the uncoupling of mu-opioid receptors from G-proteins by G-protein-coupled receptor kinase 2 in the lower midbrain may, at least in part, contribute to the suppression of the rewarding effect of morphine under neuropathic pain.
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