Afterhyperpolarization amplitude in CA1 pyramidal cells of aged Long-Evans rats characterized for individual differences

[摘要] Altered neural excitability is considered a prominent contributing factor to cognitive decline during aging. A clear example is the excess neural activity observed in several temporal lobe structures of cognitively impaired older individuals in rodents and humans. At a cellular level, aging-related changes in mechanisms regulating intrinsic excitability have been well examined in pyramidal cells of the CA1 hippocampal subfield. Studies in the inbred Fisher 344 rat strain document an age-related increase in the slow afterhyperpolarization (AHP) that normally occurs after a burst of action potentials, and serves to reduce subsequent firing. We evaluated the status of the AHP in the outbred Long-Evans rat, a well established model for studying individual differences in neurocognitive aging. In contrast to the findings reported in the Fisher 344 rats, in the Long-Evan rats we detected a selective reduction in AHP in cognitively impaired aged individuals. We discuss plausible scenarios to account for these differences and also discuss possible implications of these differences. (C) 2020 Elsevier Inc. All rights reserved.

[发布日期] 2020-12-01

[关键词] Intrinsic excitability;Cognitive decline;Current clamp;CA1;Afterhyperpolarization;sAHP