Aberrant cortical synaptic plasticity and dopaminergic dysfunction in a mouse model of huntington's disease

• Published in: Human molecular genetics 2006-10, Vol.15 (19), p.2856-2868
• Main Authors: Cummings, Damian M., Milnerwood, Austen J., Dallérac, Glenn M., Waights, Verina, Brown, Jacki Y., Vatsavayai, Sarat C., Hirst, Mark C., Murphy, Kerry P.S.J.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Cerebral Cortex; Cerebral Cortex - physiopathology; Cognitive Sciences; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Disease Models, Animal; Dopamine; Dopamine - physiology; Female; Fundamental and applied biological sciences. Psychology; Genetics of eukaryotes. Biological and molecular evolution; Humans; Huntingtin Protein; Huntington Disease; Huntington Disease - genetics; Huntington Disease - physiopathology; Life Sciences; Male; Medical sciences; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Mice, Transgenic; Molecular and cellular biology; Nerve Tissue Proteins; Nerve Tissue Proteins - genetics; Neurobiology; Neurology; Neuronal Plasticity; Neuronal Plasticity - physiology; Neurons and Cognition; Nuclear Proteins; Nuclear Proteins - genetics; Psychology and behavior; Receptors, Dopamine; Receptors, Dopamine - metabolism; Synaptic Transmission
• ISSN: 0964-6906; 1460-2083
• DOI: 10.1093/hmg/ddl224

Predictive genetic testing for Huntington's disease (HD) has revealed early cognitive deficits in asymptomatic gene carriers, such as altered working memory, executive function and impaired recognition memory. The perirhinal cortex processes aspects of recognition memory and the underlying mechanism is believed to be long-term depression (LTD) of excitatory neurotransmission, the converse of long-term potentiation (LTP). We have used the R6/1 mouse model of HD to assess synaptic plasticity in the perirhinal cortex. We report here a progressive derailment of both LTD and short-term plasticity at perirhinal synapses. Layer II/III neurones gradually lose their ability to support LTD, show early nuclear localization of mutant huntingtin and display a progressive loss of membrane integrity (depolarization and loss of cell capacitance) accompanied by a reduction in the expression of D1 and D2 dopamine receptors visualized in layer I of the perirhinal cortex. Importantly, abnormalities in both short-term and long-term plasticity can be reversed by the introduction of a D2 dopamine receptor agonist (Quinpirole), suggesting that alterations in dopaminergic signalling may underlie early cognitive dysfunction in HD.