Hippocampal long-term potentiation is reduced in mature compared to young male rats but not in female rats.
Aging is associated with a decline in cognitive function which could be due to reduced synaptic plasticity. Hippocampal long-term potentiation (LTP) is an activity-dependent form of increased transmission efficacy at synapses that is considered the basis for some forms of learning and memory. We studied the N-methyl-d-aspartic acid (NMDA) receptor-dependent LTP in the CA1 region of hippocampus in young (2 months) and mature (8 months) male and female rats. We have found that in young male rats the tetanus increased the magnitude of excitatory post-synaptic potentials to 204+/-10% of basal while in mature male rats the magnitude of the LTP was significantly lower reaching only 153+/-11% of basal. This decrease did not occur in female rats. Similar changes occurred in the content of the NMDA receptor subunits NR1 and NR2A in hippocampus. The amount of both subunits was reduced significantly (15-16%) in hippocampus of 8-month-old compared with 2-month-old male rats. This decrease was not observed in female rats. Moreover, there is a significant correlation between the content of NR1 subunit and the magnitude of the potentiation. These data suggest that some of the neurobiological changes induced in hippocampus by aging are different in males and females.
Monfort
P
P
Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Avenida Autopista del Saler, 16, 46013 Valencia, Spain.
Felipo
V
V
D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology / Q000528:radiation effects; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D006624:Hippocampus / Q000254:growth & development / Q000502:physiology*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000502:physiology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics / Q000378:metabolism; D012727:Sex Characteristics
C409466:NR1 NMDA receptor; C120997:NR2A NMDA receptor; D016194:Receptors, N-Methyl-D-Aspartate