The effect of etomidate on sensory transmission in the dorsal column pathway in the urethane-anaesthetized rat.
The effect of Etomidate, a general anaesthetic, on sensory afferent transmission was measured in the dorsal column pathway in urethane-anaesthetized rats. Extracellular recordings were made of peripherally evoked responses by single cells in the cuneate nucleus, ventroposterolateral nucleus of the thalamus and laminae IV-VI of the primary somatosensory cortex. Cortical mass responses were also recorded. In further experiments, cortical mass responses were evoked antidromically by stimulation in the pyramidal tract. The effect of incremental administration of Etomidate on evoked responses was recorded. These results are compared with the previously reported effects of urethane, a 'conventional' anaesthetic. Etomidate did not alter cuneate or ventroposterolateral thalamic cell responses but it caused a dose-dependent reduction in cortical cell responsiveness. It failed to alter antidromically evoked cortical mass responses. Etomidate differs from the majority of anaesthetics, which act in the thalamus, and appears to cause perturbation at the cortical level.
Angel
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A
The Centre for Research into anaesthetic Mechanisms, Department of Biomedical Science, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
Arnott
R H
RH
D000758:Anesthesia; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004562:Electrocardiography; D005045:Etomidate / Q000494:pharmacology*; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013003:Somatosensory Cortex / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology*; D013787:Thalamic Nuclei / Q000187:drug effects; D014520:Urethane
D018686:Anesthetics, Intravenous; D014520:Urethane; D005045:Etomidate