Caloric restriction prevents aging-associated changes in spike-mediated Ca2+ accumulation and the slow afterhyperpolarization in hippocampal CA1 pyramidal neurons.
In hippocampal pyramidal neurons from aged animals voltage-gated Ca2+ entry and the slow, post-burst afterhyperpolarization are enhanced. As a result, there is a decrease in neuronal excitability and, in turn, an alteration in synaptic plasticity. Restricting the caloric intake of a rodent is a well-known paradigm for increasing lifespan and ameliorating a number of neurodegenerative features of aging, including deficits in synaptic plasticity and cognition. Here we show in rat CA1 pyramidal neurons from aged animals (18-20 months old) that a restricted diet prevents the enhancement of dendritic spike-mediated Ca2+ accumulation. In contrast, no significant changes in the rates of Ca2+ recovery were observed suggesting that Ca2+ clearance mechanisms are not affected by aging or caloric restriction. Lastly, we found that caloric restriction also prevented the aging-associated increase in the slow, post-burst afterhyperpolarization. Our results suggest that caloric restriction-sensitive changes in Ca2+ accumulation and membrane excitability may in part account for the protective effects of dietary restriction on synaptic plasticity and learning deficits in aged animals.
Hemond
P
P
Department of Biology, University of Texas at San Antonio, San Antonio, TX 78249, USA.
Jaffe
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DB
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D031204:Caloric Restriction; D003712:Dendrites / Q000502:physiology / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods; D006624:Hippocampus / Q000166:cytology*; D066298:In Vitro Techniques; D018408:Patch-Clamp Techniques / Q000379:methods; D017966:Pyramidal Cells / Q000166:cytology / Q000502:physiology*; D051381:Rats; D011916:Rats, Inbred F344; D013997:Time Factors
D002118:Calcium