Brain neurotransmitter deficits in mice transgenic for the Huntington's disease mutation.
Huntington's disease (HD) is associated with an expansion in the CAG repeat sequence of a gene on chromosome 4, resulting in a neurodegenerative process particularly affecting the striatum and with profound but selective changes in content of various neurotransmitters. Recently, transgenic mice expressing a fragment of the human HD gene containing a large CAG expansion have been generated; these mice exhibit a progressive neurological phenotype that includes motor disturbances, as well as neuronal deficits. To investigate their underlying neurotransmitter pathology, we have determined concentrations of GABA, glutamate, and the monoamine neurotransmitters in several brain regions in these mice and control animals at times before and after the emergence of the behavioural phenotype. In contrast to the findings in HD, striatal GABA was unaffected, although a deficit was observed in the cerebellum, consistent with a dysfunction of Purkinje cells. Losses of the monoamine transmitters were observed, some of which are not seen in HD. Thus, 5-hydroxytryptamine and, to a greater extent, 5-hydroxyindoleacetic acid levels were diminished in all brain regions studied, and noradrenaline was particularly affected in the hippocampus. Dopamine was decreased in the striatum in older animals, parallelling evidence for diminished dopaminergic activity in HD.
Reynolds
G P
GP
Department of Biomedical Science, University of Sheffield, England, UK.
Dalton
C F
CF
Tillery
C L
CL
Mangiarini
L
L
Davies
S W
SW
Bates
G P
GP
D000818:Animals; D001923:Brain Chemistry / Q000235:genetics*; D004195:Disease Models, Animal; D004298:Dopamine / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000235:genetics* / Q000378:metabolism*; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation; D009410:Nerve Degeneration / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics*; D009638:Norepinephrine / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics*; D012701:Serotonin / Q000378:metabolism; D018911:Trinucleotide Repeats; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
C506812:Htt protein, mouse; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D012701:Serotonin; D018698:Glutamic Acid; D006897:Hydroxyindoleacetic Acid; D005680:gamma-Aminobutyric Acid; D004298:Dopamine; D009638:Norepinephrine