TY - JOUR
T1 - Modulation of memory with septal injections of morphine and glucose
T2 - Effects on extracellular glucose levels in the hippocampus
AU - McNay, Ewan C.
AU - Canal, Clinton E.
AU - Sherwin, Robert S.
AU - Gold, Paul E.
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2006/2/28
Y1 - 2006/2/28
N2 - The concentration of glucose in the extracellular fluid (ECF) of the hippocampus decreases substantially during memory testing on a hippocampus-dependent memory task. Administration of exogenous glucose, which enhances task performance, prevents this decrease, suggesting a relationship between hippocampal glucose availability and memory performance. In the present experiment, spontaneous alternation performance and task-related changes in hippocampal ECF glucose were assessed in rats after intraseptal administration of morphine, which impairs memory on a spontaneous alternation task, and after co-administration of intraseptal glucose, which attenuates that impairment. Consistent with previous findings, spontaneous alternation testing resulted in a decrease in hippocampal ECF glucose levels in control rats. However, rats that received intraseptal morphine prior to testing showed memory impairments and an absence of the task-related decrease in hippocampal ECF glucose levels. Intraseptal co-administration of glucose with morphine attenuated the memory impairment, and ECF glucose levels in the hippocampus decreased in a manner comparable to that seen in control rats. These data suggest that fluctuations in hippocampal ECF glucose levels may be a marker of mnemonic processing and support the view that decreases in extracellular glucose during memory testing reflect increased glucose demand during memory processing.
AB - The concentration of glucose in the extracellular fluid (ECF) of the hippocampus decreases substantially during memory testing on a hippocampus-dependent memory task. Administration of exogenous glucose, which enhances task performance, prevents this decrease, suggesting a relationship between hippocampal glucose availability and memory performance. In the present experiment, spontaneous alternation performance and task-related changes in hippocampal ECF glucose were assessed in rats after intraseptal administration of morphine, which impairs memory on a spontaneous alternation task, and after co-administration of intraseptal glucose, which attenuates that impairment. Consistent with previous findings, spontaneous alternation testing resulted in a decrease in hippocampal ECF glucose levels in control rats. However, rats that received intraseptal morphine prior to testing showed memory impairments and an absence of the task-related decrease in hippocampal ECF glucose levels. Intraseptal co-administration of glucose with morphine attenuated the memory impairment, and ECF glucose levels in the hippocampus decreased in a manner comparable to that seen in control rats. These data suggest that fluctuations in hippocampal ECF glucose levels may be a marker of mnemonic processing and support the view that decreases in extracellular glucose during memory testing reflect increased glucose demand during memory processing.
KW - Glucose
KW - Hippocampus
KW - Medial septum
KW - Memory
KW - Morphine
KW - Spontaneous alternation
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U2 - 10.1016/j.physbeh.2005.10.016
DO - 10.1016/j.physbeh.2005.10.016
M3 - Article
C2 - 16343563
AN - SCOPUS:31944444064
VL - 87
SP - 298
EP - 303
JO - Physiology and Behavior
JF - Physiology and Behavior
SN - 0031-9384
IS - 2
ER -