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ATP‐Sensitive Potassium Channels and Local Energy Demands in the Rat Hippocampus: An In Vivo Study
Author(s) -
Fellows L. K.,
Boutelle M. G.,
Fillenz M.
Publication year - 1993
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1993.tb03607.x
Subject(s) - tolbutamide , microdialysis , medicine , extracellular , potassium channel , potassium , endocrinology , chemistry , striatum , in vivo , hippocampus , hexokinase , biology , biochemistry , metabolism , glycolysis , insulin , dopamine , microbiology and biotechnology , organic chemistry
Microdialysis coupled with an enzyme‐based flow injection analysis was used to monitor brain extracellular lactate and glucose in the freely moving rat. Glucose levels reflect the balance between supply from the blood and local utilisation, and lactate efflux indicates the degree of local nonoxidative glucose metabolism. Local application of tolbutamide, a blocker of the ATP‐sensitive potassium channel, decreased extracellular glucose and lactate levels in the hippocampus but not in the striatum. The increase in glucose and lactate levels following mild behavioural stimulation was also reduced by tolbutamide in the hippocampus. Similar effects on both basal and stimulated lactate levels were obtained with local application of 10 m M glucose. These results indicate that ATP‐sensitive potassium channels are active under physiological conditions in the hippocampus and that the effects of tolbutamide can be mimicked by physiological glucose levels.