Non-volatile general anaesthetics reduce spinal activity by suppressing plateau potentials.
Non-volatile general anaesthetics are thought to reduce brain activity by potentiating inhibitory GABA(A) receptor channels but also cause adverse effects by suppress ing L-type calcium channels in the heart. In sections of the spinal cord, the non-volatile anaesthetics pentobarbital, thiopental and propofol reduced excitability of sensorimotor neurons by suppressing plateau potentials mediated by L-type calcium channels. This effect was independent of GABA(A) receptor potentiation but occurred in an overlapping concentration range. Therefore, the suppressive effect of non-volatile anaesthetics on L-type calcium channels can contribute to the reduction of spinal sensorimotor activity during anaesthesia. The results support the idea that general anaesthesia is achieved through several mechanisms and suggest that procedures for anaesthesia may be improved by combining selective agents for each mechanism in optimal concentrations.
Guertin
P A
PA
Department of Medical Physiology, Panum Institute, University of Copenhagen, Denmark.
Hounsgaard
J
J
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects; D000759:Adjuvants, Anesthesia / Q000494:pharmacology*; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D002120:Calcium Channel Agonists / Q000494:pharmacology; D015220:Calcium Channels / Q000502:physiology; D020746:Calcium Channels, L-Type; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D018756:GABA Antagonists / Q000494:pharmacology; D007395:Interneurons / Q000187:drug effects / Q000502:physiology; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology; D010424:Pentobarbital / Q000494:pharmacology*; D015742:Propofol / Q000494:pharmacology; D011963:Receptors, GABA-A / Q000502:physiology; D012701:Serotonin / Q000494:pharmacology; D013116:Spinal Cord / Q000737:chemistry / Q000166:cytology / Q000187:drug effects*; D013779:Tetrodotoxin / Q000494:pharmacology; D013874:Thiopental / Q000494:pharmacology*; D014426:Turtles
D000759:Adjuvants, Anesthesia; D018686:Anesthetics, Intravenous; D002120:Calcium Channel Agonists; D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D018756:GABA Antagonists; D011963:Receptors, GABA-A; D012701:Serotonin; D013779:Tetrodotoxin; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D010424:Pentobarbital; D013874:Thiopental; D001640:Bicuculline; D015742:Propofol