title: Brain extracellular potassium and general anaesthetics.
abstract: General anaesthetic agents (halothane, trichlorethylene, methohexital, pentobarbital, and alphaxalone--alphadolone) depress the extracellular accumulations (deltaEk) and associated focal potentials (deltaV) which are evoked in the cuneate nucleus by tetanic stimulation of peripheral nerves. Depressions of deltaV are significantly greater than those of deltaEk; at the same time there is a dissociation of the relation between deltaV and deltaEk. There are no detectable changes in the resting levels of K+ or the small voltage shifts evoked by low-frequency intranuclear stimulation with a microlectrode. When anaesthesia produces severe hypotension, augmentations of [K+]0 occur which can be attributed to depression of electrogenic Na--K pumping. A possible explanation of the reduction in K+ release resulting from afferent fibre activity would be failure of conduction caused by membrane stabilization or hyperpolarization.
mesh_terms: D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D002415:Cats; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism*; D009411:Nerve Endings / Q000502:physiology; D010525:Peripheral Nerves / Q000502:physiology; D011188:Potassium / Q000378:metabolism*
chemical_list: D000777:Anesthetics; D011188:Potassium