RESUMO
The midbrain tegmentum has been identified as an important locus for development of negative reinforcement with electrical stimulation of the brain. It also plays a central role in the motivational-affective component of pain, and is a site of the analgesic action of morphine. The present study reports the effects of morphine on the electrical activity of areas of the dorsal tegmentum of rats that were also tested for the aversive effects of brain stimulation. The results of spectral analysis of the EEG indicated that IP injections of 16 mg/kg of morphine significantly depressed intensity of EEG, while 8 mg/kg of morphine tended to increase intensity. The results were interpreted in terms of the dual action hypothesis of morphine action and Winters' model of drug effects on electrical activity of the brain. It was concluded that morphine may produce complementary inhibitory and excitatory effects on the negative and positive reinforcement systems of the brain respectively.
Assuntos
Morfina/farmacologia , Tegmento Mesencefálico/efeitos dos fármacos , Animais , Comportamento Animal/efeitos dos fármacos , Estimulação Elétrica , Eletrodos Implantados , Eletroencefalografia , Masculino , Ratos , Tegmento Mesencefálico/anatomia & histologiaAssuntos
Potenciais Evocados , Tempo de Reação , Visão Ocular , Humanos , Luz , Retina/fisiologia , Córtex Visual/fisiologiaAssuntos
Hipotálamo/efeitos dos fármacos , Morfina/farmacologia , Ritmo alfa , Animais , Ritmo beta , Computadores , Ritmo Delta , Relação Dose-Resposta a Droga , Eletroencefalografia , Injeções Intraperitoneais , Masculino , Morfina/administração & dosagem , Ratos , Reforço Psicológico , Autoestimulação/efeitos dos fármacos , Ritmo TetaAssuntos
Afasia , Linguística , Fonética , Comportamento Verbal , Adulto , Idoso , Percepção Auditiva , Humanos , Masculino , Memória de Curto Prazo , Pessoa de Meia-Idade , Modelos Teóricos , FalaAssuntos
Catolicismo , Emprego/legislação & jurisprudência , Hospitais Religiosos/legislação & jurisprudência , Corpo Clínico Hospitalar/legislação & jurisprudência , Emprego/economia , Fraude/legislação & jurisprudência , Conselho Diretor , Hospitais Religiosos/economia , Licenciamento em Medicina , Corpo Clínico Hospitalar/economia , Objetivos Organizacionais , Autorreferência Médica/legislação & jurisprudência , Corporações Profissionais/legislação & jurisprudência , Salários e Benefícios , Isenção Fiscal , Estados Unidos , Recursos HumanosRESUMO
This article examines the key provisions which should be focused on when reviewing managed care contracts. It offers guidance on how gastroenterologists can negotiate more favorable terms and avoid common contracting pitfalls. The article also highlights specific issues applicable to capitated and other risk-sharing arrangements.
Assuntos
Serviços Contratados/legislação & jurisprudência , Gastroenterologia/legislação & jurisprudência , Programas de Assistência Gerenciada/legislação & jurisprudência , Negociação , Serviços Contratados/economia , Serviços Contratados/organização & administração , Custos e Análise de Custo , Gastroenterologia/economia , Gastroenterologia/organização & administração , Humanos , Programas de Assistência Gerenciada/economia , Programas de Assistência Gerenciada/organização & administração , Estados UnidosRESUMO
Acute exposure to cocaine transiently induces several Fos family transcription factors in the nucleus accumbens, a region of the brain that is important for addiction. In contrast, chronic exposure to cocaine does not induce these proteins, but instead causes the persistent expression of highly stable isoforms of deltaFosB. deltaFosB is also induced in the nucleus accumbens by repeated exposure to other drugs of abuse, including amphetamine, morphine, nicotine and phencyclidine. The sustained accumulation of deltaFosB in the nucleus accumbens indicates that this transcription factor may mediate some of the persistent neural and behavioural plasticity that accompanies chronic drug exposure. Using transgenic mice in which deltaFosB can be induced in adults in the subset of nucleus accumbens neurons in which cocaine induces the protein, we show that deltaFosB expression increases the responsiveness of an animal to the rewarding and locomotor-activating effects of cocaine. These effects of deltaFosB appear to be mediated partly by induction of the AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole) glutamate receptor subunit GluR2 in the nucleus accumbens. These results support a model in which deltaFosB, by altering gene expression, enhances sensitivity to cocaine and may thereby contribute to cocaine addiction.