title: Increased anxiety-like behavior and selective learning impairments are concomitant to loss of hippocampal interneurons in the presymptomatic SOD1(G93A) ALS mouse model.
abstract: Amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease primarily characterized by motor neuron death, causes damages beyond motor-related areas. In particular, cognitive impairments and hippocampal damage have been reported in ALS patients. We investigated spatial navigation learning and hippocampal interneurons in a mutant SOD1(G93A) mouse (mSOD1) model of ALS. Behavioral tests were performed by using presymptomatic mSOD1 mice. General motor activity was comparable to that of wild-type mice in the open-field test, in which, however mSOD1 exhibited increased anxiety-like behavior. In the Barnes maze test, mSOD1 mice displayed a delay in learning, outperformed wild-type mice during the first probe trial, and exhibited impaired long-term memory. Stereological counts of parvalbumin-positive interneurons, which are crucial for hippocampal physiology and known to be altered in other central nervous system regions of mSOD1 mice, were also performed. At postnatal day (P) 56, the population of parvalbumin-positive interneurons in mSOD1 mice was already reduced in CA1 and in CA3, and at P90 the reduction extended to the dentate gyrus. Loss of parvalbumin-positive hippocampal interneurons occurred mostly during the presymptomatic stage. Western blot analysis showed that hippocampal parvalbumin expression levels were already reduced in mSOD1 mice at P56. The hippocampal alterations in mSOD1 mice could at least partly account for the increased anxiety-like behavior and deficits in spatial navigation learning. Our study provides evidence for cognitive alterations and damage to the γ-aminobutyric acid (GABA)ergic system in the hippocampus of murine ALS, thereby revealing selective deficits antecedent to the onset of motor symptoms.
authors: Department of Experimental and Clinical Medicine, Physiological Sciences Section, University of Florence, Florence, I-50134, Italy.
authors: Eros
authors: E
authors: Quarta
authors: Department of Experimental and Clinical Medicine, Physiological Sciences Section, University of Florence, Florence, I-50134, Italy.
authors: Riccardo
authors: R
authors: Bravi
authors: Department of Neurological and Movement Sciences, University of Verona, Verona, I-37134, Italy.
authors: Ilaria
authors: I
authors: Scambi
authors: Department of Neurological and Movement Sciences, University of Verona, Verona, I-37134, Italy.
authors: Raffaella
authors: R
authors: Mariotti
authors: Department of Experimental and Clinical Medicine, Physiological Sciences Section, University of Florence, Florence, I-50134, Italy.
authors: Diego
authors: D
authors: Minciacchi
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000473:pathology* / Q000503:physiopathology / Q000523:psychology*; D000818:Animals; D001007:Anxiety / Q000473:pathology / Q000503:physiopathology*; D004195:Disease Models, Animal; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007395:Interneurons / Q000378:metabolism / Q000473:pathology*; D007859:Learning Disabilities / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D057567:Memory, Long-Term; D008822:Mice, Transgenic; D009043:Motor Activity; D010320:Parvalbumins / Q000378:metabolism; D065854:Spatial Navigation; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D000072105:Superoxide Dismutase-1
chemical_list: D010320:Parvalbumins; C000606290:SOD1 protein, human; C000606291:Sod1 protein, mouse; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1
keywords: AB_291468; AB_298032; AB_477329; amyotrophic lateral sclerosis; anxiety; hippocampus; parvalbumin-positive interneurons; spatial navigation learning