Functional elongation of CA1 hippocampal neurons with aging in Fischer 344 rats

Turner, Dennis A.; Deupree, David L.

doi:10.1016/0197-4580(91)90098-5

Cited by 49 publications

(23 citation statements)

References 47 publications

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“…This objection is untenable, however, because it predicts changes in other physiological parameters, in particular membrane potential, unitary EPSP size, and quanta1 content. No such changes were observed in the present study, nor have differences in the resting membrane potential been found in any hippocampal subfield in previous studies (e.g., Barnes and McNaughton, 1980;Segal, 1982;Landfield and Pitler, 1984;Barnes et al, 1987;Landfield et al, 1986;Turner and Deupree, 1991). The present experiments also produced no evidence for changes in input resistance (60 young and 60 old CAI pyramidal cells).…”

Section: Discussioncontrasting

confidence: 69%

Region‐specific age effects on AMPA sensitivity: Electrophysiological evidence for loss of synaptic contacts in hippocampal field CA1

et al. 1992

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The effects of aging on the responsiveness of hippocampal neurons to iontophoretic application of L-glutamate and AMPA were studied in vitro. There were no effects of age on neuronal responses to L-glutamate; however, CA1 pyramidal cells of old rats, but not granule cells in the fascia dentata, showed both a smaller reduction in extracellularly-recorded synaptic responses following application of AMPA (presumably mediated by depolarization), and smaller extracellular "DC" fields (measured by subtracting the DC potentials at the dendrite and soma following AMPA application in the dendrites). To examine the cellular bases of this age-related alteration in AMPA sensitivity, two additional electrophysiological approaches were used: (1) measurement of the amplitude ratios of extracellular EPSP and fiber potential components of the Schaffer collateral-CA1 response; (2) measurement of intracellularly recorded unitary EPSPs and quantal analysis of their fluctuations. The interpretations that would be placed on four hypothetical possible outcomes of such experiments are outlined and assessed in relation to the experimental data. The pattern of results obtained in the present experiments supports the following conclusions: In old rats, individual Schaffer collateral synapses do not appear to have altered AMPA receptor properties, as neither the mean size of the unitary synaptic response nor the apparent quantal size differs between age groups; however, the data do support the conclusion that there are fewer synapses per Schaffer collateral branch in old versus young CA1 pyramidal cells.

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Section: Discussioncontrasting

confidence: 69%

Region‐specific age effects on AMPA sensitivity: Electrophysiological evidence for loss of synaptic contacts in hippocampal field CA1

et al. 1992

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“…The larger AHP in older rats is not a likely explanation for the age-related temporal-summation deficit, however, because Landau and colleagues have found that directly increasing the AHP during high-frequency stimulation of pyramidal cells of 6-to 8-week-old rats did not alter the total depolarization during the burst (Landau, personal communication). Changes in dendritic length and branching might also cause a deficit of temporal summation, and Turner and Deupree (1991) and Pyapali and Turner (1996) have found dendritic changes in aged rats. Other studies, however, have failed to find corresponding changes in EPSP half-width and rise time that would be consistent with large dendritic modification in old rats (Pitler and Landfield, 1990;Barnes et al, 1992Barnes et al, , 1996.…”

Section: Discussionmentioning

confidence: 98%

Role of temporal summation in age-related long-term potentiation-induction deficits

et al. 1997

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“…Studies have demonstrated that there appears to be no significant change in neuronal cell numbers in the prefrontal cortex or hippocampus of humans [4, 5], primates [6, 7], or rodents [8, 9]. Similarly, the extent of dendritic branching shows no significant age-related decline in the hippocampus of humans [10, 11], primates [12], or rodents [13]. Recent evidence suggests that the morphology of hippocampal synaptosomes and synaptic vesicles may not be altered with increased age [14].…”

Section: Introductionmentioning

confidence: 99%

Xanthohumol improved cognitive flexibility in young mice

Zamzow

Elias

Legette

et al. 2014

Behavioural Brain Research

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The protein palmitoylation cycle has been shown to be important for protein signaling and synaptic plasticity. Data from our lab showed a change in the palmitoylation status of certain proteins with age. A greater percentage of the NMDA receptor subunits GluN2A and GluN2B, along with Fyn and PSD95 proteins, were palmitoylated in the old mice. The higher level of protein palmitoylation was also associated with poorer learning scores. Xanthohumol is a prenylated flavonoid that has been shown to increase beta-oxidation in the livers of rodents, decreasing circulating free fatty acids in the serum. What is not known is whether the application of xanthohumol could influence the palmitoylation status of proteins. In this study, young and old mice were fed a diet supplemented with xanthohumol for 8 weeks. Spatial memory was assessed with the Morris water maze and protein palmitoylation quantified. The young xanthohumol-treated mice showed a significant improvement in cognitive flexibility. However, this appeared to be associated with the young control mice, on a defined, phytoestrogen-deficient diet, performing as poorly as the old mice and xanthohumol reversing this effect. The old mice receiving xanthohumol did not significantly improve their learning scores. Xanthohumol treatment was unable to affect the palmitoylation of NMDA receptor subunits and associated proteins assessed in this study. This evidence suggests that xanthohumol may play a role in improving cognitive flexability in young animals, but it appears to be ineffective in adjusting the palmitoylation status of neuronal proteins in aged individuals.

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Functional elongation of CA1 hippocampal neurons with aging in Fischer 344 rats

Cited by 49 publications

References 47 publications

Region‐specific age effects on AMPA sensitivity: Electrophysiological evidence for loss of synaptic contacts in hippocampal field CA1

Region‐specific age effects on AMPA sensitivity: Electrophysiological evidence for loss of synaptic contacts in hippocampal field CA1

Role of temporal summation in age-related long-term potentiation-induction deficits

Xanthohumol improved cognitive flexibility in young mice

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