RESUMEN
Methamphetamine neurotoxicity has been demonstrated in rodents and nonhuman primates. These neurotoxic effects may be associated with mechanisms involved in oxidative stress and the activation of immediate early genes (IEG). It is not clear, however, whether these IEG responses are involved in a methamphetamine-induced toxic cascade or in protective mechanisms against the deleterious effects of the drug. As a first step toward clarifying this issue further, the present study was thus undertaken to assess the toxic effects of methamphetamine in heterozygous and homozygous c-fos knock-out as well as wild-type mice. Administration of methamphetamine caused significant reduction in [(125)I]RTI-121-labeled dopamine uptake sites, dopamine transporter protein, and tyrosine hydroxylase-like immunohistochemistry in the striata of wild-type mice. These decreases were significantly exacerbated in heterozygous and homozygous c-fos knock-out mice, with the homozygous showing greater loss of striatal dopaminergic markers. Moreover, in comparison with wild-type animals, both genotypes of c-fos knock-out mice showed more DNA fragmentation, measured by the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeled nondopaminergic cells in their cortices and striata. In contrast, wild-type mice treated with methamphetamine demonstrated a greater number of glial fibrillary acidic protein-positive cells than did c-fos knock-out mice. These data suggest that c-fos induction in response to toxic doses of methamphetamine might be involved in protective mechanisms against this drug-induced neurotoxicity.
Asunto(s)
Corteza Cerebral/fisiología , Genes fos , Metanfetamina/toxicidad , Neuronas/fisiología , Neurotoxinas , Proteínas Proto-Oncogénicas c-fos/metabolismo , Animales , Temperatura Corporal/efectos de los fármacos , Corteza Cerebral/citología , Corteza Cerebral/efectos de los fármacos , Cuerpo Estriado/citología , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/fisiología , Fragmentación del ADN , Dopamina/metabolismo , Lóbulo Frontal/citología , Lóbulo Frontal/efectos de los fármacos , Lóbulo Frontal/fisiología , Proteína Ácida Fibrilar de la Glía/análisis , Heterocigoto , Homocigoto , Radioisótopos de Yodo , Ratones , Ratones Noqueados , Neuronas/citología , Neuronas/efectos de los fármacos , Proteínas Proto-Oncogénicas c-fos/deficiencia , Proteínas Proto-Oncogénicas c-fos/genéticaRESUMEN
Suicide is a major mental health problem in Taiwan. Estimations revealed that approximately 41% of people who committed suicide had a previous history of psychiatric inpatient care. To date, a suicide nursing care theory has not been developed. Consequently, the aim of this study was to formulate a suicide nursing care theory with the aim of enhancing and advancing the nursing care provided to people who attempt suicide or have suicidal thoughts. A qualitative approach using grounded theory was adopted. A total of 15 peoples who had either suicidal ideas or had attempted suicide and 15 psychiatric nurses were interviewed and observed. Data were analysed using open, axial and selective coding and the NUD*IST software program. A substantive theory of suicide nursing care was developed from the emergent findings. Four categories surfaced in the nursing care theory relating to the nurses' 'action/interaction strategies'. They were: the holistic assessment of people who are suicidal; providing protection; providing basic care; and providing advanced care. The findings from this study could be used to influence and advance nurse education and training, clinical practice, management and further research.
Asunto(s)
Relaciones Enfermero-Paciente , Servicio de Psiquiatría en Hospital , Prevención del Suicidio , Intento de Suicidio/prevención & control , Adolescente , Adulto , Estudios Transversales , Femenino , Grupos Focales , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Evaluación en Enfermería , Teoría de Enfermería , Admisión del Paciente/estadística & datos numéricos , Planificación de Atención al Paciente , Servicio de Psiquiatría en Hospital/estadística & datos numéricos , Suicidio/psicología , Suicidio/estadística & datos numéricos , Intento de Suicidio/psicología , Intento de Suicidio/estadística & datos numéricos , TaiwánRESUMEN
In recent years the suicide rates have been increasing gradually in many countries. In order to reduce the number of suicides, further research on suicide and the nursing care of suicidal people is required to enhance and advance the quality of suicide nursing care provided. Statistical evidence shows that the most common method of completing suicide in many countries is hanging. Other evidence demonstrates that some suicides could be prevented if all patients were assessed for suicide risk and if psychiatric nurses provided effective nursing care, which centres on therapeutic communication skills. This paper explores the literature on suicide and on the nursing care of people who are suicidal, and also on the importance of integrating theory with practice.
Asunto(s)
Trastornos Mentales , Enfermería Psiquiátrica/organización & administración , Prevención del Suicidio , Suicidio , Adolescente , Adulto , Anciano , Actitud del Personal de Salud , Competencia Clínica , Comunicación , Femenino , Conocimientos, Actitudes y Práctica en Salud , Humanos , Masculino , Trastornos Mentales/etnología , Trastornos Mentales/enfermería , Persona de Mediana Edad , Rol de la Enfermera , Relaciones Enfermero-Paciente , Evaluación en Enfermería , Investigación en Evaluación de Enfermería , Teoría de Enfermería , Prevención Primaria , Enfermería Psiquiátrica/educación , Calidad de la Atención de Salud/organización & administración , Medición de Riesgo , Factores de Riesgo , Suicidio/etnología , Suicidio/estadística & datos numéricos , Taiwán/epidemiologíaRESUMEN
BACKGROUND AND PURPOSE: Previous studies have indicated that both methamphetamine (MA) and ischemia/reperfusion injuries involve reactive oxygen species formation and activation of apoptotic mechanism. That MA could have a synergistic or additive effect with stroke-induced brain damage is possible. The purpose of the present study was to investigate whether administration of MA in vivo would potentiate ischemic brain injury. METHODS: Adult CD-1 mice were pretreated with MA or saline. Each animal later was anesthetized with chloral hydrate and placed in a stereotaxic frame. A subset of animals received intracerebral administration of glial cell line-derived neurotrophic factor (GDNF). The right middle cerebral artery and bilateral carotids were transiently occluded for 45 minutes. Regional cerebral blood flow was measured by laser Doppler. Animals were sacrificed for triphenyltetrazolium chloride staining and p53 mRNA Northern blot assay after 24 hours of reperfusion. Cortical and striatal GDNF levels were assayed by ELISA. RESULTS: We found that pretreatment with MA increased ischemia-induced cerebral infarction. Ischemia or MA alone enhanced p53 mRNA expression. Moreover, MA potentiated expression of p53 mRNA in the ischemic mouse brain. MA pretreatment decreased GDNF levels in ischemic striatum. Intracerebral administration of GDNF before ischemia reduced MA-facilitated infarction. CONCLUSIONS: Our data indicate that MA exacerbates ischemic insults in brain, perhaps through the inhibition of GDNF-mediated pathways and suggest that MA may antagonize endogenous neuroprotective pathways as part of its mechanism of action.
Asunto(s)
Infarto de la Arteria Cerebral Media/metabolismo , Metanfetamina/farmacología , Factores de Crecimiento Nervioso , Daño por Reperfusión/metabolismo , Animales , Velocidad del Flujo Sanguíneo/efectos de los fármacos , Análisis de los Gases de la Sangre , Presión Sanguínea/efectos de los fármacos , Calcio/metabolismo , Corteza Cerebral/irrigación sanguínea , Corteza Cerebral/efectos de los fármacos , Corteza Cerebral/patología , Circulación Cerebrovascular/efectos de los fármacos , Cuerpo Estriado/irrigación sanguínea , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/patología , Modelos Animales de Enfermedad , Ensayo de Inmunoadsorción Enzimática , Factor Neurotrófico Derivado de la Línea Celular Glial , Frecuencia Cardíaca/efectos de los fármacos , Infarto de la Arteria Cerebral Media/complicaciones , Infarto de la Arteria Cerebral Media/patología , Inyecciones Intraventriculares , Ligadura , Masculino , Ratones , Proteínas del Tejido Nervioso/administración & dosificación , Proteínas del Tejido Nervioso/metabolismo , ARN Mensajero/metabolismo , Especies Reactivas de Oxígeno , Daño por Reperfusión/etiología , Daño por Reperfusión/patología , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
The psychostimulant methamphetamine, both in vivo and in vitro, caused a mitochondrial cytochrome c release, the translocation of Bax from cytosol into mitochondrion, and the oligomerization of Bax. These effects by methamphetamine were blocked by a neuroprotective and hibernation-induction delta opioid peptide [D-Ala2,D-Leu5]enkephalin (DADLE). These results suggest that methamphetamine causes apoptosis by affecting the dynamics of Bax and that the neuroprotective property of DADLE may be due partly to its ability to potently block Bax-related apoptotic processes.
Asunto(s)
Apoptosis/efectos de los fármacos , Estimulantes del Sistema Nervioso Central/antagonistas & inhibidores , Estimulantes del Sistema Nervioso Central/farmacología , Leucina Encefalina-2-Alanina/farmacología , Metanfetamina/antagonistas & inhibidores , Metanfetamina/farmacología , Proteínas Proto-Oncogénicas c-bcl-2/antagonistas & inhibidores , Proteínas Proto-Oncogénicas/antagonistas & inhibidores , Proteínas Proto-Oncogénicas/farmacología , Animales , Western Blotting , Grupo Citocromo c/metabolismo , Citosol/efectos de los fármacos , Citosol/enzimología , Masculino , Ratones , Mitocondrias/efectos de los fármacos , Mitocondrias/enzimología , Receptores Opioides delta/efectos de los fármacos , Proteína X Asociada a bcl-2RESUMEN
Interaction of sigma receptors with intracellular Ca2+ channel blocker and modulators was examined. Ryanodine and inositol 1,4,5-trisphosphate (IP3) did not inhibit [3H](+)-N-allylnormetazocine ([3H](+)-SKF-10047) binding to sigma receptors from either brain microsomal fractions or liver membrane extracts of the rat. However, the IP3 receptor antagonist heparin inhibited [3H](+)-SKF-10047 to sigma receptors in an uncompetitive manner with a Ki of 93 microM. These results suggest that sigma receptors may bear some relationship with IP3 receptor associated proteins or channels.
Asunto(s)
Canales de Calcio/química , Heparina/farmacología , Fenazocina/análogos & derivados , Receptores Citoplasmáticos y Nucleares/química , Receptores Opioides delta/antagonistas & inhibidores , Animales , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Retículo Endoplásmico/efectos de los fármacos , Retículo Endoplásmico/metabolismo , Técnicas In Vitro , Receptores de Inositol 1,4,5-Trifosfato , Cinética , Microsomas/efectos de los fármacos , Microsomas/metabolismo , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/metabolismo , Fenazocina/farmacología , Ratas , Receptores Opioides delta/efectos de los fármacos , Rianodina/farmacologíaRESUMEN
[D-Ala(2), D-Leu(5)]enkephalin (DADLE) has been previously reported to prolong the survival of tissues both in the periphery and in the central nervous system. Here, we show that DADLE was able to block the protein as well as the functional loss of dopamine transporter (DAT) and tyrosine hydroxylase (TH) induced by methamphetamine. Male CD-1 mice received four injections of methamphetamine (10 mg/kg, i.p. ) at 2-h intervals. DADLE (4 mg/kg, i.p.) was given 30 min before each injection of methamphetamine. Western blotting and enzymatic assays showed that DADLE blocked the protein loss and functional impairment of DAT and TH induced by methamphetamine.
Asunto(s)
Proteínas Portadoras/antagonistas & inhibidores , Dopaminérgicos/farmacología , Encefalinas/farmacología , Glicoproteínas de Membrana , Proteínas de Transporte de Membrana , Metanfetamina/farmacología , Proteínas del Tejido Nervioso , Tirosina 3-Monooxigenasa/antagonistas & inhibidores , Análisis de Varianza , Animales , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática , Masculino , RatonesRESUMEN
The administration of methamphetamine caused an increase of c-fos mRNA in the striatum of the mouse. A systemic injection of the delta-opioid receptor agonist, [D-Ala2, D-Leu5]enkephalin (DADLE), attenuated the c-fos mRNA increase induced by methamphetamine. These results suggest that endogenous delta-opioid peptides might counteract certain genomic influences exerted by psychostimulants such as methamphetamine.
Asunto(s)
Estimulantes del Sistema Nervioso Central/farmacología , Leucina Encefalina-2-Alanina/farmacología , Genes fos/genética , Metanfetamina/farmacología , Neostriado/efectos de los fármacos , ARN Mensajero/efectos de los fármacos , Animales , Northern Blotting , Masculino , Ratones , Neostriado/metabolismo , ARN Mensajero/metabolismoRESUMEN
A single administration of 40 mg/kg (i.p.) of methamphetamine caused a loss of dopamine transporter in the striatum of albino Swiss (CD-1) mouse for at least 3 weeks. The administration of a single dose of [D-Ala2,D-Leu5]enkephalin (DADLE) (18 mg/kg, i.p.), given at day 14 after the administration of methamphetamine, caused a significant, transient restoration of dopamine transporter level in the striatum. These results suggest that delta-opioid peptide DADLE is able to reverse the neuronal damage caused by methamphetamine.
Asunto(s)
Proteínas Portadoras/efectos de los fármacos , Cuerpo Estriado/efectos de los fármacos , Inhibidores de Captación de Dopamina/farmacología , Leucina Encefalina-2-Alanina/farmacología , Glicoproteínas de Membrana , Proteínas de Transporte de Membrana , Metanfetamina/farmacología , Proteínas del Tejido Nervioso , Animales , Proteínas Portadoras/antagonistas & inhibidores , Proteínas Portadoras/metabolismo , Cuerpo Estriado/metabolismo , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática , Inhibidores de Captación de Dopamina/administración & dosificación , Leucina Encefalina-2-Alanina/administración & dosificación , Masculino , Metanfetamina/administración & dosificación , RatonesRESUMEN
Phospholipids with diacetylenes present in the acyl chains form tubules and helices in aqueous dispersions. In order to modulate the morphology of bilayer structures and to understand the role of diacetylene in lipid-bilayer assembly, two diacetylenic phosphocholines, 1,2-bis(9,16-dioxa-hexacosa-11,13-diynoyl)-sn-3-phosph ocholine and 1,2-bis(15-oxa-pentacosa-10,12-diynoyl)-sn-3-phosphocholine, in which the diacetylene is linked to the acyl chain by an oxygen spacer have been synthesized. Lipid dispersions were characterized by calorimetric, film balance and microscopic techniques. Placement of oxygen spacer influences the morphology of the bilayer assemblies formed in aqueous solution. When both ends of the diacetylene were linked to the acyl chain by oxygen atoms, liposomes (diameters ranging from 0.3-3.4 microns) were observed by optical microscopy. Linking only the terminal portion of the acyl chain to the diacetylene with an oxygen atom resulted in a lipid which formed tubular microstructures as well as vesicles. Diameter of the tubular structures ranged from 0.4-4.7 microns. Transmission electron microscopic (TEM) analysis of replicas of a freeze fractured sample of the dispersion revealed that the tubular structures were hollow cylinders consisting of an aqueous core surrounded by a wall of lipid.
Asunto(s)
Alquinos/química , Membrana Dobles de Lípidos , Oxígeno/química , Fosfatidilcolinas/química , Fosforilcolina/química , Diinos , Técnica de Fractura por Congelación , Microscopía Electrónica , Conformación Molecular , TermodinámicaRESUMEN
A naloxone-sensitive, haloperidol-sensitive, [3H](+)SKF-10047-binding protein was partially purified from rat liver and rat brain membranes in an affinity chromatography originally designed to purify sigma receptors. Detergent-solubilized extracts from membranes were adsorbed to Sephadex G-25 resin containing an affinity ligand for sigma receptors: N-(2- 3,4-dichlorophenyl]ethyl)-N-(6-aminohexyl)-(2-[1-pyrrolidinyl]) ethylamine (DAPE). After eluting the resin with haloperidol, a protein that bound [3H](+)SKF-10047 was detected in the eluates. However, the protein was not the sigma receptor. [3H](+)SKF-10047 binding to the protein was inhibited by the following compounds in the order of decreasing potency: (+)pentazocine > (-) pentazocine > (+/-)cyclazocine > (-)morphine > (-)naloxone > haloperidol > (+)SKF-10047 > DADLE > (-)SKF-10047. Further, the prototypic sigma receptor ligands, such as 1,3-di-o-tolylguanidine (DTG), (+)3-PPP, and progesterone, bound poorly to the protein. Tryptic digestion and heat treatment of the affinity-purified protein abolished radioligand binding. Sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS/PAGE) of the partially-purified protein from the liver revealed a major diffuse band with a molecular mass of 31 kDa, a polypeptide of 65 kDa, and another polypeptide of > 97 kDa. This study demonstrates the existence of a novel protein in the rat liver and rat brain which binds opioids, benzomorphans, and haloperidol with namomolar affinity. The protein resembles the opioid/sigma receptor originally proposed by Martin et al. [(1976): J. Pharmacol. Exp. Ther., 197:517-532.]. A high degree of purification of this protein has been achieved in the present study.
Asunto(s)
Antipsicóticos/farmacología , Encéfalo/metabolismo , Hígado/metabolismo , Naloxona/farmacología , Fenazocina/análogos & derivados , Receptores Opioides/efectos de los fármacos , Animales , Haloperidol/farmacología , Fenazocina/farmacología , Ensayo de Unión Radioligante , RatasRESUMEN
The delta opioid peptide [D-Ala2, D-Leu5]enkephalin (DADLE) has been reported to block the neurotoxicity induced by multiple administrations of a moderate dose of methamphetamine (METH). We examined in this study if DADLE might block the neurotoxicity caused by a single high dose of METH in CD-1 mice. The levels of dopamine transporter (DAT), tyrosine hydroxylase (TH), major biogenic amines including DA, 5-hydroxytryptamine (5-HT), and their metabolites were examined. In addition, since the tumor suppressor p53 has been implicated in the neurotoxicity of METH, this study also examined the levels of p53 mRNA and protein affected by METH and DADLE. METH (25 mg/kg, i.p.) caused significant losses of DAT, TH, DA, 3,4-dihydroxyphenylacetic acid (DOPAC), and 5-HT in the striatum within 72 h. The administration of a single dose of DADLE (20 mg/kg, i.p., 30 min before METH) caused a complete blockade of all losses induced by METH except for that of the DA content (a approximately 50% blockade). DADLE did not affect the changes of rectal temperature induced by the administration of the high dose of METH. METH increased p53 mRNA in the striatum and the hippocampus of CD-1 mouse. DADLE abolished the p53 mRNA increase caused by METH. METH tended to increase the p53 protein level at earlier time points. However, METH significantly decreased the p53 protein level by about 30% at the 72-h time point. DADLE blocked both the increase of p53 mRNA and the decrease of p53 protein caused by METH. These results demonstrate a neuroprotective effect of DADLE against the neuronal damage and the alteration of p53 gene expression caused by a single high dose of METH. The results also indicate an apparent discordance between the protein level of p53 and the neurotoxicity caused by a high dose of METH. Synapse 39:305-312, 2001. Published 2001 Wiley-Liss, Inc.
Asunto(s)
Estimulantes del Sistema Nervioso Central/toxicidad , Leucina Encefalina-2-Alanina/uso terapéutico , Glicoproteínas de Membrana , Proteínas de Transporte de Membrana , Metanfetamina/toxicidad , Degeneración Nerviosa/tratamiento farmacológico , Proteínas del Tejido Nervioso , Fármacos Neuroprotectores/uso terapéutico , Proteína p53 Supresora de Tumor/fisiología , Animales , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Proteínas Portadoras/metabolismo , Estimulantes del Sistema Nervioso Central/administración & dosificación , Dopamina/metabolismo , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática , Cinética , Masculino , Metanfetamina/administración & dosificación , Ratones , Degeneración Nerviosa/metabolismo , Serotonina/metabolismo , Transcripción Genética/efectos de los fármacos , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo , Tirosina 3-Monooxigenasa/metabolismoRESUMEN
Delta opioid peptide [D-Ala2,D-leu5]enkephalin (DADLE) can prolong organ preservation and increases myocardial tolerance to ischemia. Our study examined the protective property of DADLE against methamphetamine- (METH) induced dopaminergic terminal damage in the central nervous system. Because the neurotoxicity of METH involves reactive oxygen species, we also examined if DADLE might be an antioxidative agent in vitro. DADLE at 2 and 4 mg/kg (i.p.), given 30 min before each METH administration (5 or 10 mg/kg, i.p., four injections in a day at 2-hr intervals), dose-dependently blocked the METH-induced long-term dopamine transporter loss. The opioid antagonist naltrexone blocked this action of DADLE in both aspects of striata but tends not to affect the effects of DADLE in the nucleus accumbens. DADLE did not alter changes in body temperature induced by METH. The reduction of striatal dopaminergic content and tyrosine hydroxylase activity caused by METH, however, were not blocked by DADLE. In vitro, DADLE was approximately equipotent to glutathione in inhibiting both superoxide anion formation induced by xanthine oxidase and hydroxyl radical formation evoked by ferrous/citrate complex. DADLE was only slightly less potent than glutathione in inhibiting the iron/ascorbate-induced brain lipid peroxidation. These results suggest that DADLE can protect the terminal membranes of dopaminergic neurons against METH-induced insult but not the loss of dopaminergic content and tyrosine hydroxylase activity and that this action of DADLE might involve opioid receptors as well as the sequestration of free radical.
Asunto(s)
Antioxidantes/farmacología , Proteínas Portadoras/efectos de los fármacos , Leucina Encefalina-2-Alanina/farmacología , Glicoproteínas de Membrana , Proteínas de Transporte de Membrana , Metanfetamina/toxicidad , Proteínas del Tejido Nervioso , Especies Reactivas de Oxígeno , Receptores Opioides/efectos de los fármacos , Animales , Temperatura Corporal/efectos de los fármacos , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática , Glutatión/farmacología , Masculino , Ratones , Naltrexona/farmacología , Receptores Opioides/fisiologíaRESUMEN
In vitro studies were performed to characterize [3H]cocaine binding to dark and light ethnic hair types. In vitro binding to hair was selective, was reversible and increased linearly with increasing hair concentration. Scatchard analyses revealed high-affinity (6-112 nM) and low-affinity (906-4433 nM) binding in hair. Competition studies demonstrated that the potencies of 3beta-(4-bromophenyl)tropane-2beta-carboxylic acid methyl ester, and 5-(4-chlorophenyl)-2,5-dihydro-3H-imidazol[2,1-alpha]isoindole-5-ol and 2beta-carbomethoxy-3beta-(4-fluorophenyl)tropane were similar to or less than that of (-)-cocaine. The potency of (-)-cocaine was 10-fold greater than that of (+)-cocaine at inhibiting radioligand specific binding to hair. Multivariate analysis indicated that significantly greater nonspecific and specific radioligand binding occurred in dark hair than in light hair. Multivariate analysis also demonstrated a significant ethnicity x sex effect on specific and nonspecific binding to hair. Greater radioligand binding occurred in male Africoid hair than in female Africoid hair and in all Caucasoid hair types. Melanin was considered the most likely binding site for cocaine in hair. Typically, the concentration of melanin is much greater in dark than in light hair. Scatchard analysis indicated that dark hair had a 5- to 43-fold greater binding capacity than light hair. Differences in radioligand binding between hair types appeared to be due to differences in the density of binding sites formed by melanin in hair.