title: Aged wild-type and APP, PS1, and APP + PS1 mice present similar deficits in associative learning and synaptic plasticity independent of amyloid load.
abstract: Wild-type and single-transgenic (APP, PS1) and double-transgenic (APP+PS1) mice were studied at three different (3-, 12-, and 18-month-old) age periods. Transgenic mice had reflex eyelid responses like those of controls, but only 3-month-old mice were able to fully acquire conditioned eyeblinks, using a trace paradigm, whilst 12-month-old wild-type and transgenic mice presented intermediate values, and 18-month-old wild-type and transgenic mice were unable to acquire this type of associative learning. 18-month-old wild-type and transgenic mice presented a normal synaptic activation of CA1 pyramidal cells by the stimulation of Schaffer collaterals, but they did not show any activity-dependent potentiation of the CA3-CA1 synapse across conditioning sessions, as was shown by 3-month-old wild-type mice. Moreover, 18-month-old wild-type and transgenic mice presented a noticeable deficit in long-term potentiation evoked in vivo at the hippocampal CA3-CA1 synapse. The 18-month-old wild-type and transgenic mice also presented a significant deficit in prepulse inhibition as compared with 3-month-old controls. Except for results collected by prepulse inhibition, the above-mentioned deficits were not related with the presence of amyloid beta deposits. Thus, learning and memory deficits observed in aged wild-type and transgenic mice are not directly related to the genetic manipulations or to the presence of amyloid plaques.
authors.affiliation: División de Neurociencias, Universidad Pablo de Olavide, 41013 Sevilla, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Gruart
authors.affiliation: División de Neurociencias, Universidad Pablo de Olavide, 41013 Sevilla, Spain.
authors.forename: J C
authors.initials: JC
authors.lastname: López-Ramos
authors.affiliation: Departamento de Investigación, Hospital Ramón y Cajal, 28034 Madrid, Spain.
authors.forename: M D
authors.initials: MD
authors.lastname: Muñoz
authors.affiliation: División de Neurociencias, Universidad Pablo de Olavide, 41013 Sevilla, Spain. Electronic address: jmdelgar@upo.es.
authors.forename: J M
authors.initials: JM
authors.lastname: Delgado-García
mesh_terms: D000375:Aging / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000235:genetics*; D016564:Amyloid beta-Protein Precursor / Q000235:genetics*; D000818:Animals; D001245:Association Learning / Q000502:physiology*; D003214:Conditioning, Classical / Q000502:physiology; D008297:Male; D008569:Memory Disorders / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009473:Neuronal Plasticity / Q000235:genetics* / Q000502:physiology; D058225:Plaque, Amyloid / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D053764:Presenilin-1 / Q000096:biosynthesis / Q000235:genetics*; D013569:Synapses / Q000235:genetics / Q000378:metabolism / Q000473:pathology
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D053764:Presenilin-1