title: A behavioral and micro positron emission tomography imaging study in a rat model of hypothyroidism.
abstract: Hypothyroidism leads to somatic, neuropsychological, and psychiatric changes that are similar to depression. The mechanisms underlying the behavioral abnormalities in adult onset hypothyroidism remain ambiguous. Hypothyroidism was induced in adult male Wistar rats by the maintenance of 0.05% propylthiouracil (PTU) in drinking water for 5 weeks (hypothyroid group; HP group); control rats (CON group) received an equivalent amount of water. The open field and sucrose preference tests were employed, and the link between behavioral changes and brain glucose metabolism was evaluated using micro positron emission tomography imaging. The open field test revealed slightly decreased locomotor activity and significantly reduced rearing and defecation in the hypothyroid group. Hypothyroid rats were also characterized by decreased body weight, sucrose preference, and relative sucrose intake compared to control rats. Hypothyroidism induced reduced brain glucose metabolism in the bilateral motor cortex, the caudate putamen, the cortex cingulate, the nucleus accumbens, and the frontal association cortex. A decreased sucrose preference was positively correlated with metabolic glucose changes in the caudate putamen and the nucleus accumbens. The results indicate that the activity pattern in adult onset hypothyroidism is different from the activity pattern when hypothyroidism is induced in the developmental period of the central nervous system. Decreased sucrose preference in hypothyroid rats may be attributed to anhedonia. Furthermore, these findings suggest there may be a common mechanism underlying adult onset hypothyroidism and depression.
authors.affiliation: Institute of Neuroinformatics, Dalian University of Technology, Dalian 116023, China; Nuclear Medicine Division, Second Affiliated Hospital, Dalian Medical University, Dalian 116027, China. Electronic address: 13941156265@163.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Yu
authors.affiliation: Institute of Neuroinformatics, Dalian University of Technology, Dalian 116023, China; Texas Tech Neuroimaging Institute & Department of Psychology, Texas Tech University, MS 3132, Lubbock, TX 79409, USA.
authors.forename: Yi-Yuang
authors.initials: YY
authors.lastname: Tang
authors.affiliation: Nuclear Medicine Division, First Affiliated Hospital, Dalian Medical University, Dalian 116011, China.
authors.forename: Hong-Bo
authors.initials: HB
authors.lastname: Feng
authors.affiliation: Cancer Institute and The Liaoning Provincial Key Laboratory of Cancer Genomics, College of Basic Medical Science, Dalian Medical University, Dalian 116023, China.
authors.forename: Xiao-Xin
authors.initials: XX
authors.lastname: Cheng
mesh_terms: D000818:Animals; D013956:Antithyroid Agents / Q000008:administration & dosage / Q000506:poisoning; D001835:Body Weight; D001921:Brain / Q000378:metabolism*; D004195:Disease Models, Animal; D060766:Drinking Water; D005518:Food Preferences; D005947:Glucose / Q000378:metabolism; D007037:Hypothyroidism / Q000139:chemically induced / Q000378:metabolism* / Q000523:psychology*; D008124:Locomotion; D008297:Male; D009043:Motor Activity; D049268:Positron-Emission Tomography; D011441:Propylthiouracil / Q000008:administration & dosage / Q000506:poisoning; D051381:Rats; D017208:Rats, Wistar; D013395:Sucrose
chemical_list: D013956:Antithyroid Agents; D060766:Drinking Water; D013395:Sucrose; D011441:Propylthiouracil; D005947:Glucose
keywords: Depression; Hypothyroidism; Micro positron emission tomography; Open field; Sucrose preference