Ablation of D1 dopamine receptor-expressing cells generates mice with seizures, dystonia, hyperactivity, and impaired oral behavior
journal contribution
posted on 2023-05-18, 11:37authored byGantios, I, Fang, K, Jiang, L, Babovic, D, Lawrence, AL, Ferreri, V, Teper, Y, Jupp, B, Jenna ZiebellJenna Ziebell, Morganti-Kossmann, CM, O'Brien, TJ, Nally, R, Schutz, G, Waddington, J, Egan, GF, Drago, J
Huntington's disease is characterized by death of striatal projection neurons. We used a Cre/Lox transgenic approach to generate an animal model in which D1 dopamine receptor (Drd1a)+ cells are progressively ablated in the postnatal brain. Striatal Drd1a, substance P, and dynorphin expression is progressively lost, whereas D2 dopamine receptor (Drd2) and enkephalin expression is up-regulated. Magnetic resonance spectroscopic analysis demonstrated early elevation of the striatal choline/creatine ratio, a finding associated with extensive reactive striatal astrogliosis. Sequential MRI demonstrated a progressive reduction in striatal volume and secondary ventricular enlargement confirmed to be due to loss of striatal cells. Mutant mice had normal gait and rotarod performance but displayed hindlimb dystonia, locomotor hyperactivity, and handling-induced electrographically verified spontaneous seizures. Ethological assessment identified an increase in rearing and impairments in the oral behaviors of sifting and chewing. In line with the limbic seizure profile, cell loss, astrogliosis, microgliosis, and down-regulated dynorphin expression were seen in the hippocampal dentate gyrus. This study specifically implicates Drd1a+ cell loss with tail suspension hindlimb dystonia, hyperactivity, and abnormal oral function. The latter may relate to the speech and swallowing disturbances and the classic sign of tongueprotrusion motor impersistence observed in Huntington's disease. In addition, the findings of this study support the notion that Drd1a and Drd2 are segregated on striatal projection neurons.
History
Publication title
National Academy of Sciences of The United States of America. Proceedings
Volume
104
Issue
10
Pagination
4182-4187
ISSN
0027-8424
Department/School
Wicking Dementia Research Education Centre
Publisher
Natl Acad Sciences
Place of publication
United States
Rights statement
Copyright 2007 The National Academy of Sciences of the USA