RESUMO
Effects of noxious skin stimulation (central foot pad and foot dorsum) by radiant heat were tested on neurones of ascending tracts with a main input from non-nociceptors. The dominating effect on ventral spinocerebellar tract neurones was a depression (mainly from the pad). Responses of spinocervical tract neurones were either facilitated (predominantly from the foot dorsum) or depressed (predominantly from the pad). The dominating effect on neurones tentatively classified as dorsal horn dorsal spinocerebellar tract neurones was facilitatory from both skin areas. Similar effects were evoked by selective actions of C-fibres when A-delta fibres were blocked by TTX.
Assuntos
Vias Aferentes/fisiologia , Músculos/inervação , Neurônios/fisiologia , Limiar da Dor/fisiologia , Pele/inervação , Vias Aferentes/citologia , Vias Aferentes/efeitos dos fármacos , Animais , Gatos , Potenciais Evocados/efeitos dos fármacos , Potenciais Evocados/fisiologia , Membro Posterior/inervação , Temperatura Alta , Neurônios/classificação , Neurônios/efeitos dos fármacos , Medição da Dor/efeitos dos fármacos , Medula Espinal/citologia , Medula Espinal/efeitos dos fármacos , Medula Espinal/fisiologia , Tratos Espinocerebelares/efeitos dos fármacos , Tratos Espinocerebelares/fisiologia , Tetrodotoxina/farmacologiaAssuntos
Consumo de Bebidas Alcoólicas , Condução de Veículo , Etanol/sangue , Acidentes de Trânsito/prevenção & controle , Adulto , Idoso , Alcoolismo/sangue , Alcoolismo/diagnóstico , Testes Respiratórios , Feminino , Medicina Legal , Humanos , Masculino , Programas de Rastreamento , Pessoa de Meia-Idade , Projetos de Pesquisa , Fatores de Risco , Inquéritos e QuestionáriosRESUMO
Effects of noxious stimulation of the skin by radiant heat were tested on responses of first order interneurones in reflex pathways from group II muscle afferents in mid-lumbar, lower-lumbar and sacral segments of the spinal cord. In mid- and lower-lumbar segments both background discharges and monosynaptically evoked responses of intermediate zone interneurones were facilitated. Those of mid-lumbar dorsal horn interneurones were also facilitated suggesting that both these interneuronal populations contribute to the facilitation of flexion reflexes by nociceptors. In contrast, the dominating effects of noxious heat on sacral dorsal horn group II interneurones were inhibitory. The effects evoked by selective activation of C fibres, after A-delta fibres had been blocked by TTX, were similar to those obtained before TTX application.
