Bone marrow transplantation during the 1995 Hanshin earthquake disaster.
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Biomedical subjects
Publications and source records attributed to M Misawa.
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BACKGROUND: Salsolinol, a condensation product of dopamine with acetaldehyde (the initial oxidation product of ethanol), has long been discussed as an endogenous opioid system-activating factor contributing to the etiology of alcoholism. Moreover, psychological stress has been considered to play an important role in the development of alcoholism. METHODS: Male Sprague Dawley rats were subjected to conditioned fear stress (at 24 hr after electric footshock exposure), and then salsolinol or saline was injected intraperitoneally. For conditioning, rats were immediately confined to the nonpreferred compartment after salsolinol injection and to the preferred compartment after saline injection on alternate days. This conditioning session was repeated twice daily (for 8 days). Test session was carried out 1 day after the last conditioning session. RESULTS: Salsolinol [10 mg/kg, but not 1, 3, or 30 mg/kg, intraperitoneally (ip)] without conditioned fear stress induced a slight, but significant, place preference. In contrast, salsolinol (1, 3, and 10 mg/kg, ip) with conditioned fear stress induced a marked and significant place preference. The nonselective opioid receptor antagonist naloxone hydrochloride (which can pass into the brain), but not the nonselective peripheral opioid receptor antagonist naloxone methiodide (which cannot pass into the brain), significantly attenuated the salsolinol (3 mg/kg, ip)-induced place preference under conditioned fear stress. Moreover, the selective mu-opioid receptor antagonist beta-funaltrexamine significantly attenuated the salsolinol-induced place preference. Furthermore, 0.3 mg/kg salsolinol (which produced no significant place preference) combined with the mu-opioid receptor agonist morphine [0.1 mg/kg, subcutaneously (sc)], at the dose which alone produced no significant place preference, produced a marked and significant place preference. Both naloxone hydrochloride and beta-funaltrexamine significantly attenuated the salsolinol plus morphine-induced place preference. CONCLUSIONS: Salsolinol may have some rewarding effect, and its rewarding effect may be potentiated by psychological stress. In addition, the rewarding effect of salsolinol especially under psychological stress may involve the endogenous central opioid system, i.e., mu-opioid receptor.
The effects of the 5-HT(3) receptor antagonist ondansetron on the ketamine- and dizocilpine-induced place preferences in mice were examined. The non-competitive NMDA receptor antagonists ketamine (1. 0-10 mg/kg, i.p.) and dizocilpine (0.1 and 0.2 mg/kg, i.p.) each produced a place preference in a dose-dependent manner. The ketamine (10 mg/kg)- and dizocilpine (0.2 mg/kg)-induced place preferences were dose-dependently blocked by pretreatment with ondansetron (0. 03-0.1 mg/kg, s.c.). These results suggest that 5-HT(3) receptor may be involved in the development of the place preferences produced by ketamine and dizocilpine.
The present study was designed to investigate: (1) the involvement of dopamine D(1) and D(2) receptors, and (2) the roles of these receptors and endogenous opioid systems (endorphinergic and enkephalinergic systems) in the ethanol-induced place preference in rats exposed to conditioned fear stress using the conditioned place preference paradigm. The administration of ethanol (300 mg/kg, i.p.) induced a significant place preference. The selective D(1) receptor antagonist R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4, 5-tetrahydro-1H3-benzazepine)hydrochloride (SCH23390; 0.01 and 0.03 mg/kg, s.c.) and the selective D(2) receptor antagonist S(-)-5-(aminosulfonyl)-N-[(1-ethyl-2-pyrrolidinyl)-methyl]-2- methoxybenzamide (sulpiride; 20 and 40 mg/kg, s.c.) significantly attenuated the ethanol-induced place preference. The administration of ethanol (75 mg/kg, i.p.) tended to produce a place preference, but this effect was not significant. SCH23390 (0.03 mg/kg, s.c.) and sulpiride (40 mg/kg, s.c.) significantly attenuated the enhancement of the ethanol (75 mg/kg, i.p.)-induced place preference produced by the mu-opioid receptor agonist morphine (0.1 mg/kg, s.c.). In addition, SCH23390 (0.03 mg/kg, s.c.) also significantly attenuated the enhancement of the ethanol (75 mg/kg, i.p.)-induced place preference produced by the selective delta-opioid receptor agonist 2-methyl-4aalpha-(3-hydroxyphenyl)-1,2,3,4,4a,5,12, 12aalpha-octahydroquinolino[2,3,3,-g]isoquinoline (TAN-67; 20 mg/kg, s.c.). On the other hand, sulpiride (40 mg/kg) had no significant effect on the enhancement of the ethanol (75 mg/kg, i.p.)-induced place preference produced by TAN-67. These results suggest that D(1) and D(2) receptors may be involved in the rewarding mechanism of ethanol under psychological stress. In addition, D(1) receptors may participate in the rewarding effect of ethanol modulated by the activation of mu- and delta-opioid receptors, whereas D(2) receptors may participate in the rewarding effect of ethanol modulated by the activation of mu-opioid receptors, but not in that modulated by the activation of delta-opioid receptors.
To clarify the contribution of metabotropic glutamate (mGlu) receptors in brain to benzodiazepine withdrawal signs, we now examine the effects in mice of selective ligands for three subgroups of mGlu receptor on the hypersusceptibility to pentylenetetrazole-induced seizure during diazepam withdrawal. The seizure threshold for pentylenetetrazole was significantly decreased by the discontinuation of chronic diazepam treatment. The decrease in the seizure threshold for pentylenetetrazole during diazepam withdrawal was significantly suppressed by intracerebroventricular (i.c.v.) pretreatment with the group 1 mGlu receptor antagonist, (S)-4-carboxyphenylglycine ((S)-4CPG: 56 and 100 nmol). These doses of (S)-4CPG did not alter the seizure threshold in chronically vehicle-treated (control) mice. Pretreatment i.c.v. with a presynaptic mGlu receptor agonist (the group 2 mGlu receptor agonist (2S,1'S,2'S)-2-(carboxycyclopropyl)-glycine (L-CCG-I: 3.0 and 5.6 nmol) and the group 3 mGlu receptor agonist, L-amino-4-phosphonobutyric acid (L-AP4: 3.0 and 5.6 nmol)) failed to suppress the decrease in seizure threshold in diazepam-withdrawn mice, but increased the seizure threshold in control mice. Pretreatment i.c.v. with the group 1 mGlu receptor antagonist/group 2 mGlu receptor agonist, (S)-4-carboxy-3-hydroxyphenylglycine ((S)-4C3HPG: 56 and 100 nmol), significantly increased the seizure threshold in control mice and suppressed the decrease in seizure threshold in diazepam-withdrawn mice. These findings suggest that enhancement of group 1 mGlu receptor function and a decline in both group 2 and group 3 mGlu receptor functions may play an important role in the hypersusceptibility to pentylenetetrazole-induced seizure during diazepam withdrawal.
Many studies have indicated that Lewis and Fischer 344 inbred rat strains show marked differences in behavioral responses to abused drugs. In the present study, we sought to determine whether these two strains of rats show different responses in mecamylamine-precipitated nicotine-withdrawal aversion using the conditioned place preference paradigm. Rats were treated subcutaneously with 10 mg/kg/day nicotine for 7 days using an osmotic minipump. After chronic nicotine infusion, the nicotinic receptor antagonist mecamylamine produced a significant place aversion in Lewis, but not in Fischer 344 rats. These results suggest that mecamylamine-precipitated nicotine-withdrawal aversion is strongly regulated by genetic factors.
The present study was designed to investigate the role of the endogenous opioid system in the development of ethanol-induced place preference in rats exposed to conditioned fear stress (exposure to an environment paired previously with electric foot shock), using the conditioned place preference paradigm. The administration of ethanol (300 mg/kg, i.p.) with conditioned fear stress induced significant place preference. Naloxone (1 and 3 mg/kg, s.c.), a non-selective opioid receptor antagonist, significantly attenuated this ethanol-induced place preference. Moreover, the selective mu-opioid receptor antagonist beta-funaltrexamine (3 and 10 mg/kg, i.p.) and the selective delta-opioid receptor antagonist naltrindole (1 and 3 mg/kg, s.c.) significantly attenuated ethanol-induced place preference. In contrast, the selective kappa-opioid receptor antagonist nor-binaltorphimine (3 mg/kg, i.p.) significantly enhanced ethanol-induced place preference. Furthermore, 75 mg/kg ethanol (which tended to produce place preference) combined with the mu-opioid receptor agonist morphine (0.1 mg/kg, s.c.) or the selective delta-opioid receptor agonist 2-methyl-4aalpha-(3-hydroxyphenyl)-1,2,3,4,4a,5,12,12aalpha- octahydroquinolino [2,3,3,-g] isoquinoline (TAN-67; 20 mg/kg, s.c.), at doses which alone did not produce place preference, produced significant place preference. However, co-administration of the selective kappa-opioid receptor agonist trans-3,4-dichloro-N-(2-(1-pyrrolidinyl)cyclohexyl)benzenacetamide methanesulfonate (U50,488H; 0.3 and 1 mg/kg, s.c.) with ethanol (300 mg/kg, i.p.) dose dependently attenuated ethanol-induced place preference. Moreover, conditioned fear stress shifted the response curve for the aversive effect of U50,488H to the left. These results suggest that mu- and delta-opioid receptors may play critical roles in the rewarding mechanism of ethanol, and that kappa-opioid receptors may modulate the development of the rewarding effect of ethanol under psychological stress.
We previously reported that the morphine-induced place preference was attenuated under inflammation produced by the unilateral injection of 2.5 % formalin (50 microl) into the hind paw of rats. In the present study, to elucidate the mechanism of this attenuation, the effects of pretreatment with delta- and kappa-opioid receptor antagonists, naltrindole (NTI) and nor-binaltorphimine (nor-BNI), on the development of the morphine-induced place preference under inflammation were examined in rats. Nor-BNI, but not NTI, eliminated the suppression of the morphine-induced place preference in inflamed groups. These results suggest that endogenous kappa-opioid systems may be activated in the presence of chronic inflammatory nociception; as a result, the development of morphine's rewarding effect may be suppressed under inflammation.
The effects of ifenprodil, a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist, on the morphine-induced place preference were examined in mice. Morphine (1-5 mg/kg, s.c.) produced a dose-related place preference in mice. In contrast, ifenprodil alone (5-20 mg/kg, i.p.) did not produce either preference or aversion for the drug-associated place. Pretreatment with ifenprodil (5-20 mg/kg, i.p.) suppressed the place preference produced by morphine in a dose-dependent manner. These results indicate that ifenprodil suppresses the rewarding effect produced by morphine.
The effect of the selective 5-HT3 receptor antagonist ondansetron on the ethanol-induced place preference in rats exposed to conditioned fear stress, which stimulates the release of endogenous opioid peptides (beta-endorphin and enkephalins), was investigated using the conditioned place preference paradigm. In addition, we also examined the effect of ondansetron on the ethanol-induced place preference enhanced by the administration of mu- and delta-opioid receptor agonists (exogenous opioids). The administration of ethanol (300 mg/kg, i.p.) induced a significant place preference in rats exposed to conditioned fear stress. Pretreatment with ondansetron (0.01 and 0.1 mg/kg, s.c.) effectively attenuated this ethanol-induced place preference. When the mu-opioid receptor agonist morphine (0.1 mg/kg, s.c.) or the selective delta-opioid receptor agonist 2-methyl-4a(alpha)-(3-hydroxyphenyl)-1,2,3,4,4a,5,12,12a(alpha)-octah ydroquinolino [2,3,3-g] isoquinoline (TAN-67; 20 mg/kg, s.c.) was administered in combination with 75 mg/kg ethanol (which tended to produce a place preference), the ethanol-induced place preference was significantly enhanced. The selective mu-opioid receptor antagonist beta-funaltrexamine at a dose of 10 mg/kg significantly attenuated the enhancement of the ethanol-induced place preference produced by morphine. Ondansetron (0.1 mg/kg, s.c.) also significantly attenuated the enhancement of the ethanol-induced place preference produced by morphine. Furthermore, the selective delta-opioid receptor antagonist naltrindole at a dose of 3 mg/kg significantly attenuated the enhancement of the ethanol-induced place preference produced by TAN-67. Ondansetron (0.1 mg/kg, s.c.) slightly, but significantly, attenuated the enhancement of the ethanol-induced place preference produced by TAN-67. These results suggest that 5-HT3 receptors may be involved in the rewarding mechanism of ethanol under psychological stress, and may play an important role in the rewarding effect of ethanol through the activation of mu- and delta-opioid receptors.
Treatment with acetylcholine (ACh) of a beta-escin-permeabilized intrapulmonary bronchial smooth muscle of the rat induced force when the Ca2+ concentration was clamped at 1 microM. The ACh-induced Ca2+ sensitization of myofilaments was significantly greater in antigen-induced airway hyperresponsive rats than in control rats. The ACh-induced Ca2+ sensitization was completely blocked by treatment with Clostridium botulinum C3 exoenzyme, an inactivator of Rho family of proteins. Moreover, the protein level of RhoA in the intrapulmonary bronchi was significantly increased in the airway hyperresponsive rats. Thus, increased airway smooth muscle contractility observed in asthmatics may be related to augmented agonist-induced, Rho-mediated Ca2+ sensitization of myofilaments.
PURPOSE: To evaluate the practical value of initial C-reactive protein (CRP) in the diagnosis of bacterial infection in children. METHODS: The subjects comprised 11 children, six boys and five girls, aged 3 months through to 3 years (median age 16 months), whose initial CRP levels were < 1.0 mg/dL despite bacterial infection. C-reactive protein was quantitated at the first medical examination by nephelometry. RESULTS: The diagnosis was urinary tract infection (n = 4), bacterial meningitis (n = 2), sepsis (n = 2), pneumonia (n = 2) and arthritis of the hip joint (n = 1). The CRP levels were significantly elevated during the course of infection, ranging from 7.6 to 28.5 mg/dL. The bacterial etiology was non-specific. Eight patients were examined within 12 h of onset, three exhibited negative CRP values despite the duration of the insult over 12 h. Six patients were tentatively diagnosed as having a bacterial infection, but the other five were not. Each patient was treated, leading to a favorable outcome without any serious complications. CONCLUSIONS: Low levels of CRP do not rule out the possibility of bacterial infection in children. The initial value of CRP may be negative, even in patients with severe bacterial infection or even after 12 h from onset. The data suggest that pediatricians should consistently be aware of the possibility of bacterial infection even if the initial CRP test result is negative and that serial CRP measurements appear to be practical.
Nonspecific airway hyperresponsiveness (AHR) is a common feature of allergic bronchial asthmatics, but the underlying mechanism (s) of AHR have yet to be elucidated. The importance of AHR in the pathogenesis of asthma has been suggested by its relevance to the severity of this disease. There is thus a need to understand the underlying mechanisms of AHR for the sake of asthma therapy. In the present minireview, we discussed the involvement of the augmented agonist-induced Ca2+ sensitization of airway smooth muscle contraction in the pathogenesis of AHR. Treatment with acetylcholine (ACh) of a beta-escin-permeabilized intrapulmonary bronchial smooth muscle of the rat induced a stronger contractile force even when the Ca2+ concentration was clamped at 1 microM. The ACh-induced Ca2+ sensitization of myofilaments was found to be significantly greater in antigen-induced airway hyperresponsive rats than in control rats. The ACh-induced Ca2+ sensitization was completely blocked by treatment with Clostridium botulinum C3 exoenzyme, an inactivator of the Rho family proteins. Moreover, the protein level of RhoA in the intrapulmonary bronchi was demonstrated to be significantly increased in the airway hyperresponsive rats. Thus, the increased airway smooth muscle contractility observed in asthmatics may be related to the augmented agonist-induced, Rho-mediated Ca2+ sensitization of myofilaments.
The place preferences by some histamine H1 antagonists, such as tripelennamine, optical isomers of chlorpheniramine (dl-, d- and l-forms) and pyrilamine, in rats were evaluated with the conditioned place preference paradigm. In the present study, tripelennamine and all of the optical isomers of chlorpheniramine, but not pyrilamine, produced a significant place preference. The degree of the place preference induced by optical isomers of chlorpheniramine (6.0 mg/kg) did not correlate with the H1-antagonistic potency of these drugs, suggesting that H1-antagonist-induced place preferences are not mediated by H1-receptor blockade. The tripelennamine (3.0 mg/kg)- and dl-chlorpheniramine (6.0 mg/kg)-induced place preferences were completely abolished by pretreatment with the dopamine D1-receptor antagonist SCH23390 (0.05 mg/kg). Furthermore, the doses of H1 antagonists that induced a place preference significantly reduced the levels of DOPAC, which may be mediated by inhibition of dopamine uptake, in the limbic forebrain (including the nucleus accumbens and olfactory tubercle). These results suggest that some H1 antagonists induce rewarding effects, which may be mediated by the activation of dopamine D1 receptors, followed by the inhibition of dopamine uptake.
To investigate the alteration in acetylcholine (ACh)-induced increase in Ca2+ sensitization of bronchial smooth muscle contraction concurrent with the airway hyperresponsiveness (AHR), the ACh-induced increases in cytosolic Ca2+ ([Ca2+]) level and contractile response were simultaneously determined by using Fura-2 loaded bronchial smooth muscle. The left main bronchi were isolated from AHR rats which were sensitized and repeatedly challenged with DNP-Ascaris antigen. The tissue ring preparations were incubated in loading solution containing 10 microM Fura-2AM for 3 hr at room temperature. Then the isometrical contraction and [Ca2+]i (F340/F380) were monitored. Although the ACh (10(-3) M)-induced contractile response in AHR group (322 +/- 60 % of 60 mM K+ induced contraction) was significantly greater than that in control animals (173 +/- 15 %, p<0.05), the ACh (10(-3) M)-induced increase in [Ca2+]i was without significant difference between the two groups (128 +/- 15 and 171 +/- 29% of 60 mM K+ -induced increase in [Ca2+]i, respectively). These findings suggest that an augmentation of ACh-induced Ca2+ sensitization may occur in bronchial smooth muscle of the rats with antigen-induced AHR.
The purpose of this study was to establish the ethanol-induced place preference in rats exposed to foot shock stress using the conditioned place preference paradigm. We also investigated the role of the endogenous opioid system in the development of the ethanol-induced place preference. The administration of ethanol (300 mg/kg, i.p.) with foot shock stress, but not without such stress, induced a marked and significant place preference. Naloxone (1 and 3 mg/kg, s.c.), a non-selective opioid receptor antagonist, significantly attenuated the ethanol-induced place preference. Moreover, the selective mu-opioid receptor antagonist beta-funaltrexamine (3 and 10 mg/kg, i.p.) and selective delta-opioid receptor antagonist naltrindole (1 and 3 mg/kg, s.c.), but not the selective kappa-opioid receptor antagonist nor-binaltorphimine (1 and 3 mg/kg, i.p.), significantly attenuated the ethanol-induced place preference. Furthermore, 150 mg/kg ethanol (which tended to produce a place preference, although not significantly) combined with each dose (that did not produce a place preference) of the mu-opioid receptor agonist morphine (0.1 mg/kg, s.c.) or selective delta-opioid receptor agonist 2-methyl-4aalpha-(3-hydroxyphenyl)-1,2,3,4,4a,5,12, 12aalpha-octahydroquinolino [2,3,3-g] isoquinoline (TAN-67; 20 mg/kg, s.c.), but not the selective kappa-opioid receptor agonist trans-3, 4-dichloro-N-(2-(1-pyrrolidinyl)cyclohexyl)benzenacetamide methanesulfonate (U50,488H; 1 mg/kg, s.c.), produced a significant place preference. These data indicate that stress may be important for development of the rewarding effect of ethanol, and that mu- and delta-opioid receptors may be involved in the rewarding mechanism of ethanol under stressful conditions.
The present study investigated the effects of the NMDA receptor antagonists dizocilpine (MK-801) and ifenprodil on the appearance of diazepam withdrawal signs caused by discontinuation of long-term diazepam treatment using a drug-admixed food (DAF) method in Fischer 344 rats. The total withdrawal score was significantly decreased by after-withdrawal treatment with dizocilpine or ifenprodil. Dizocilpine, in particular, markedly suppressed the motor withdrawal signs and body weight loss, while ifenprodil suppressed the motor and emotional withdrawal signs. Furthermore, the decrease in the food intake during withdrawal (anorexia) was significantly reduced by dizocilpine, but not by ifenprodil. These behavioral results indicated that the activation of NMDA receptors during withdrawal may play an important role in the appearance of withdrawal signs (in particular motor withdrawal signs) caused by discontinuation of chronic diazepam treatment, and that inhibitory agents for NMDA receptors may be effective in alleviation of the appearance of benzodiazepine withdrawal signs.
The decrease in the seizure threshold for pentylenetetrazole in diazepam-withdrawn mice was not significantly affected by L-arginine (50 and 100 microg/mouse, i.c.v.), which did have an antiseizure effect in chronically vehicle-treated mice. Sodium nitroprusside (25 and 50 microg/mouse, i.c.v.) increased the seizure threshold for pentylenetetrazole in both diazepam-withdrawn mice and chronically vehicle-treated mice. In addition, the antiseizure effect of L-arginine was blocked by the nitric oxide (NO) synthase inhibitor, N-nitro-L-arginine (NOARG) and the NO scavenger, hemoglobin, while the effect of sodium nitroprusside was inhibited by hemoglobin, but not by NOARG, indicating that the antiseizure effect of L-arginine, but not that of sodium nitroprusside, is mediated by NO production resulting from the activation of NO synthase. Therefore, a decrease in the NO production via NO synthase may be involved in the hypersusceptibility to pentylenetetrazole during diazepam withdrawal.