RESUMO
The effect on arterial pressure, EEG, preganglionic sympathetic nervous activity and pulse rate of repeated intravenous administrations of lidocaine (3 mg/kg) was investigated in cats anaesthetized with nitrous oxide. A continuous high voltage, burst-suppression EEG indicating constant seizure activity was found, whereas arterial pressure and sympathetic nervous activity did not change significantly. Although the onset of EEG seizure activity did not change the mean sympathetic activity level, the pattern of firing changed dramatically as every EEG seizure triggered a burst of sympathetic impulses. Barostatic reflexes were active after lidocaine administration unless seizure activity occurred. Thiopental 5 mg/kg given intravenously to cats during continuous lidocaine-induced EEG seizures always abolished the seizure activity without excessive depression of arterial pressure.
Assuntos
Lidocaína , Convulsões/induzido quimicamente , Sistema Nervoso Simpático/fisiopatologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Gatos , Eletroencefalografia , Gânglios Autônomos/efeitos dos fármacos , Injeções Intravenosas , Lidocaína/administração & dosagem , Lidocaína/antagonistas & inibidores , Pressorreceptores/efeitos dos fármacos , Pulso Arterial/efeitos dos fármacos , Convulsões/fisiopatologia , Tiopental/farmacologiaRESUMO
We have studied the effects of etomidate on preganglionic cervical sympathetic activity, arterial pressure, and pulse rate. Normal and baroreceptor-denervated animals were studied. On the basis of findings it is concluded that etomidate exerts a minimal direct depressant action on the cardiovascular system. A profound depression of sympathetic tone was observed in spite of unaffected arterial pressure. Etomidate was also shown to possess a mild vagolytic action.
Assuntos
Pressão Sanguínea/efeitos dos fármacos , Etomidato/farmacologia , Imidazóis/farmacologia , Pulso Arterial/efeitos dos fármacos , Sistema Nervoso Simpático/efeitos dos fármacos , Animais , Gatos , Denervação , SimpatectomiaRESUMO
We have studied the effects of propanidid on preganglionic cervical sympathetic nervous activity, arterial pressure, pulse rate and barostatic reflexes of the cat. Normal, hypertensive, baroreceptor denervated and decerebrate animals with sectioned vagal nerves were studied. On the basis of our findings it is concluded that propanidid exerts its depressant action on the cardiovascular system directly. Central circulatory control mechanisms are essentially unaffected. The depression of arterial pressure caused by propanidid is moderated by two compensatory mechanisms: normal barostatic reflexes causing an increased sympathetic tone in response to hypotension and a vagolytic action of propanidid.
Assuntos
Pressão Sanguínea/efeitos dos fármacos , Pressorreceptores/efeitos dos fármacos , Propanidida/farmacologia , Pulso Arterial/efeitos dos fármacos , Reflexo/efeitos dos fármacos , Sistema Nervoso Simpático/efeitos dos fármacos , Animais , Fibras Autônomas Pré-Ganglionares/efeitos dos fármacos , Gatos , Estado de Descerebração/fisiopatologia , Denervação , Hipertensão/fisiopatologia , Norepinefrina/farmacologia , Pressorreceptores/fisiologia , Fatores de Tempo , VagotomiaAssuntos
Sistema Nervoso Autônomo/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Isoflurano/farmacologia , Éteres Metílicos/farmacologia , Pressorreceptores/efeitos dos fármacos , Pulso Arterial/efeitos dos fármacos , Animais , Gatos , Estado de Descerebração/fisiopatologia , Denervação , Estimulação Elétrica , Pressorreceptores/fisiologia , Reflexo/efeitos dos fármacos , Sistema Nervoso Simpático/efeitos dos fármacos , Sistema Nervoso Simpático/fisiologia , Fatores de Tempo , Nervo Vago/efeitos dos fármacos , Nervo Vago/fisiologiaRESUMO
We have studied the effects of Althesin on preganglionic cervical sympathetic nervous activity, arterial pressure, pulse rate and barostatic reflexes in cats. Normal, baroreceptor denervated and decerebrate animals were studied. On the basis of our finding it is concluded that Althesin severely depresses sympathetic nervous activity by action on the vasomotor centre. The depression of arterial pressure however was only moderate due to two compensatory mechanisms: a vagolytic action of Althesin and a peripheral vascular effect believed to be caused by an enhanced action of catecholamines caused by Althesin. Barostatic reflexes were found active under conditions where Althesin did not totally abolish sympathetic tone.
