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The acoustic intermodulation distortion product 2f1-f2 (ADP) was measured in human subjects to investigate (1) the dependence of ADP level on stimulus parameters and (2) the relationship between ADP level and auditory sensitivity. The frequency ratio (f2/f1), at which ADP level is maximal, varies only slightly across frequency and subjects. The average(More)
We tested the hypothesis that astrocytic glycogen sustains axon function during and enhances axon survival after 60 min of glucose deprivation. Axon function in the rat optic nerve (RON), a CNS white matter tract, was monitored by measuring the area of the stimulus-evoked compound action potential (CAP). Switching to glucose-free artificial CSF (aCSF) had(More)
CNS glycogen, contained predominantly in astrocytes, can be converted to a monocarboxylate and transported to axons as an energy source during aglycaemia. We analysed glycogen regulation and the role of glycogen in supporting neural activity in adult mouse optic nerve, a favourable white matter preparation. Axon function was quantified by measuring the(More)
Measurements of extracellular space volume and imaging of intrinsic optical signals (IOSs) have shown that neuronal activity increases light transmittance by causing cellular swelling. However, the cellular mechanisms underlying these volume changes and the contribution of astrocyte swelling to the changes in tissue volume are unclear. In this study, we(More)
The pharmacological properties of 1,4-dideoxy-1,4-imino-d-arabinitol (DAB), a potent inhibitor of glycogen phosphorylase and synthase activity in liver preparations, were characterized in different brain tissue preparations as a prerequisite for using it as a tool to investigate brain glycogen metabolism. Its inhibitory effect on glycogen phosphorylase was(More)
Axon function in the CNS has been reported to fail rapidly during anoxia, implying that there is no anaerobic capacity. This phenomenon was reassessed in rodent white matter using mouse or rat optic nerve. Axon function was semiquantitatively measured as area under the compound action potential. Mouse optic nerves exposed to anoxia (30-180 minutes) or(More)
RATIONALE Current antipsychotics are ineffective at treating the negative and cognitive symptoms of schizophrenia, so there is a substantial need to develop more effective therapeutics for this debilitating disorder. The type II metabotropic glutamate receptor (mGluR2/3) is a novel, potential therapeutic target requiring evaluation in appropriate(More)
The authors investigated ionic mechanisms underlying aglycemic axon injury in adult rat optic nerve, a central white matter tract. Axon function was assessed using evoked compound action potentials (CAPs). Glucose withdrawal led to delayed CAP failure, an alkaline extracellular pH shift, and an increase in extracellular [K(+)]. Sixty minutes of glucose(More)
1. As a first step toward identification of the functional significance of the spatial distribution of calcium channels we examined the high voltage-activated calcium current (HVA current) in acutely isolated pyramidal neurons from rat sensorimotor cortex using whole-cell voltage clamp. The goals of this study were (1) to determine whether the(More)
We tested the hypothesis that non-glucose energy sources can support axon function in the rat optic nerve. Axon function was assessed by monitoring the stimulus-evoked compound action potential (CAP). CAP was maintained at full amplitude for 2 hr in 10 mM glucose. 20 mM lactate, 20 mM pyruvate, 10 mM fructose, or 10 mM mannose supported axon function as(More)