LOXL null mice demonstrate selective dentate structural changes but maintain dentate granule cell and CA1 pyramidal cell potentiation in the hippocampus.

Nathan W Bronson; Jock S Hamilton; Mei Han; Ping-An Li; Ian Hornstra; John M Horowitz; Barbara A Horwitz

doi:10.1016/j.neulet.2005.08.021

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LOXL null mice demonstrate selective dentate structural changes but maintain dentate granule cell and CA1 pyramidal cell potentiation in the hippocampus.

Nathan W Bronson·Jock S Hamilton·Mei Han·Ping-An Li·Ian Hornstra·John M Horowitz·Barbara A Horwitz

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Abstract

Lysyl oxidase-like protein (LOXL), part of the lysyl oxidase copper-dependent amine oxidase family, is expressed in the extracellular matrix and in the nucleus. It likely plays a role in cross-linking collagen and elastin, possibly modulating cellular functions. Immunohistochemical studies show the presence of LOXL in the pyramidal cell layer of the hippocampus; and in this study, we report that cells in the granule cell layer have significantly smaller somas in LOXL -/- compared to LOXL +/+ mice. In addition we tested the hypothesis that these structural alterations in the dentate granule layer were associated with synaptic efficacy and thus muted long-term potentiation in mice lacking the protein. Electrical recordings were obtained in 300-mum hippocampal slices in dentate and CA1 pyramidal cell layers in age-matched wild type and LOXL null mice. Potentiation in the CA1 cell layer of 10 LOXL -/- and 8 LOXL +/+ mice was 191.0+/-9.3% and 181.6+/-9.1%, respectively (mean+/-S.E.M.). Dentate potentiation was 120.8+/-7.0% and 121.0+/-3.4% in 11 LOXL -/- and 11 LOXL +/+ mice, respectively. No phenotypic difference in potentiation of population spike amplitude (or in EPSP slope) in either layer was observed. Thus, contrary to expectation, structural changes in the hippocampus of LOXL -/- mice did not affect synaptic remodeling in a manner that impaired the establishment of LTP.

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Amino Acid Oxidoreductases Animals Cell Shape Dentate Gyrus Electrophysiology Female Hippocampus Long-Term Potentiation Male Mice Mice, Knockout Neurons Pyramidal Cells Synaptic Transmission Journal Article Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S.

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Nathan W Bronson, Jock S Hamilton, Mei Han, Ping-An Li, Ian Hornstra, John M Horowitz, Barbara A Horwitz. 2005-12-23. LOXL null mice demonstrate selective dentate structural changes but maintain dentate granule cell and CA1 pyramidal cell potentiation in the hippocampus.. https://doi.org/10.1016/j.neulet.2005.08.021

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