title: Altered serotonin receptor expression is associated with depression-related behavior in the R6/1 transgenic mouse model of Huntington's disease.
abstract: Dysregulation of the serotonergic signaling system has been implicated in the pathology of mood disorders including depression, and various rodent models of disrupted serotonergic signaling display depression-related behavioral phenotypes. Depression is a common neuropsychiatric feature of preclinical Huntington's disease (HD) but the underlying changes in the HD brain contributing to the development of depression are unknown. Using the R6/1 transgenic mouse model of HD, we show that pre-motor symptomatic HD mice display sex-specific depressive-related behaviors on the forced-swim (FST), tail-suspension (TST) and novelty-suppressed feeding (NSFT) tests while having muted responses to acute anti-depressant administration. The baseline behaviors of HD mice were similar to the behavioral phenotypes of serotonin (5-HT) receptor and transporter null mutants, and gene expression of specific serotonin receptors were subsequently found to be reduced in the hippocampus and cortex of HD mice. Female HD mice had an additional deficit in cortical expression of serotonin transporter (SerT). Environmental enrichment normalized the FST behavioral response of female HD mice corresponding with increased gene expression of specific 5-HT receptors in the hippocampus and cortex. Our findings implicate altered serotonergic signaling as the basis for the development of depression during the preclinical stages of HD.
authors.affiliation: Howard Florey Institute, University of Melbourne, Victoria, Australia. terence.pang@florey.edu.au
authors.forename: Terence Y C
authors.initials: TY
authors.lastname: Pang
authors.forename: Xin
authors.initials: X
authors.lastname: Du
authors.forename: Michelle S
authors.initials: MS
authors.lastname: Zajac
authors.forename: Monique L
authors.initials: ML
authors.lastname: Howard
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Hannan
mesh_terms: D000818:Animals; D000928:Antidepressive Agents / Q000008:administration & dosage; D001522:Behavior, Animal; D001835:Body Weight; D001921:Brain / Q000378:metabolism / Q000503:physiopathology; D003863:Depression / Q000503:physiopathology*; D004195:Disease Models, Animal; D005260:Female; D015870:Gene Expression; D006801:Humans; D006816:Huntington Disease / Q000188:drug therapy / Q000235:genetics / Q000503:physiopathology / Q000523:psychology*; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009043:Motor Activity; D044302:Receptor, Serotonin, 5-HT1B / Q000235:genetics / Q000378:metabolism*; D011985:Receptors, Serotonin / Q000235:genetics / Q000378:metabolism*; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D013045:Species Specificity
chemical_list: D000928:Antidepressive Agents; D044302:Receptor, Serotonin, 5-HT1B; D011985:Receptors, Serotonin; D050486:Serotonin Plasma Membrane Transport Proteins; C112812:serotonin 1C receptor