Action potential throughput in aged rat hippocampal neurons: Regulation by selective forms of hyperpolarization

NEUROBIOLOGY OF AGING

卷:30

Article

Gant, John C.¹  Thibault, Olivier¹ 

[1] Univ Kentucky, Med Ctr, Dept Mol & Biomed Pharmacol, Lexington, KY 40536 USA

关键词: Synaptic hyperpolarization;    Aging;    Calcium;    Theta;    Fidelity;    Facilitation;    Hippocampus;    AHP;    Frequency;    Accommodation;   

DOI  :  10.1016/j.neurobiolaging.2008.02.006

来源: Elsevier

【 摘 要 】

At hippocampal synapses, repetitive synaptic stimulation (RSS) in the theta frequency range (3-12 Hz) is associatee with robust EPSP frequency facilitation (FF) and consequently, enhanced action potential (spike) generation and throughput A complex, synaptically induced hyperpolarization (SIHP) is also triggered by synaptic activation, and a Ca2+-dependent after hyperpolarization (AHP) is triggered above spike threshold. With aging, the AHP is increased and impairs intracellular spike generation, at least in accommodation protocols. However, little is known about how these aging changes interact to affect spike generation at physiological frequencies of RSS, or if the SIHP also is modified in aging. Here we performed the first tests of the net impact of these excitatory and inhibitory aging changes on spike generation during RSS We report that during RSS at spike threshold (1) spike throughput is well sustained at theta frequencies in young and aged neurons; (2) an interposed AHP dampens spike generation, particularly in aged neurons and at higher frequencies, (3) compared to the AHP, the SIHP does not exert an equivalent inhibitory effect on spike throughput, and (4) in contrast to the AHP, the SIHP is reduced with aging Together, these results are consistent with a model in which the source of the hyperpolarization is important in determining hippocampal spike throughput within the theta frequency range. (C) 2008 Elsevier Inc. All rights reserved.

【 授权许可】

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