TY  - JOUR
A1  - Waider, Jonas
A1  - Popp, Sandy
A1  - Mlinar, Boris
A1  - Montalbano, Alberto
A1  - Bonfiglio, Francesco
A1  - Aboagye, Benjamin
A1  - Thuy, Elisabeth
A1  - Kern, Raphael
A1  - Thiel, Christopher
A1  - Araragi, Naozumi
A1  - Svirin, Evgeniy
A1  - Schmitt-Böhrer, Angelika G.
A1  - Corradetti, Renato
A1  - Lowry, Christopher A.
A1  - Lesch, Klaus-Peter
T1  - Serotonin deficiency increases context-dependent fear learning through modulation of hippocampal activity
JF  - Frontiers in Neuroscience
N2  - Brain serotonin (5-hydroxytryptamine, 5-HT) system dysfunction is implicated in exaggerated fear responses triggering various anxiety-, stress-, and trauma-related disorders. However, the underlying mechanisms are not well understood. Here, we investigated the impact of constitutively inactivated 5-HT synthesis on context-dependent fear learning and extinction using tryptophan hydroxylase 2 (Tph2) knockout mice. Fear conditioning and context-dependent fear memory extinction paradigms were combined with c-Fos imaging and electrophysiological recordings in the dorsal hippocampus (dHip). Tph2 mutant mice, completely devoid of 5-HT synthesis in brain, displayed accelerated fear memory formation and increased locomotor responses to foot shock. Furthermore, recall of context-dependent fear memory was increased. The behavioral responses were associated with increased c-Fos expression in the dHip and resistance to foot shock-induced impairment of hippocampal long-term potentiation (LTP). In conclusion, increased context-dependent fear memory resulting from brain 5-HT deficiency involves dysfunction of the hippocampal circuitry controlling contextual representation of fear-related behavioral responses.
KW  - tryptophan hydroxylase 2
KW  - knockout
KW  - fear learning
KW  - extinction
KW  - long-term potentiation
KW  - hippocampus
KW  - immediate-early gene
KW  - serotonin deficiency
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-196077
SN  - 1662-453X
VL  - 13
IS  - 245
ER  - 
TY  - JOUR
A1  - Veniaminova, Ekaterina
A1  - Cespuglio, Raymond
A1  - Chernukha, Irina
A1  - Schmitt-Boehrer, Angelika G.
A1  - Morozov, Sergey
A1  - Kalueff, Allan V.
A1  - Kuznetsova, Oxana
A1  - Anthony, Daniel C.
A1  - Lesch, Klaus-Peter
A1  - Strekalova, Tatyana
T1  - Metabolic, Molecular, and Behavioral Effects of Western Diet in Serotonin Transporter-Deficient Mice: Rescue by Heterozygosity?
JF  - Frontiers in Neuroscience
N2  - Reduced function of the serotonin transporter (SERT) is associated with increased susceptibility to anxiety and depression and with type-2 diabetes, which is especially true in older women. Preference for a “Western diet” (WD), enriched with saturated fat, cholesterol, and sugars, may aggravate these conditions. In previous studies, decreased glucose tolerance, central and peripheral inflammation, dyslipidemia, emotional, cognitive, and social abnormalities were reported in WD-fed young female mice. We investigated the metabolic, molecular, and behavioral changes associated with a 3-week-long dietary regime of either the WD or control diet in 12-month-old female mice with three different Sert genotypes: homozygous (Slc6a4) gene knockout (Sert\(^{−/−}\): KO), heterozygous (Sert\(^{+/−}\): HET), or wild-type mice (Sert\(^{+/+}\): WT). In the WT-WD and KO-WD groups, but not in HET-WD-fed mice, most of changes induced by the WD paralleled those found in the younger mice, including brain overexpression of inflammatory marker Toll-like receptor 4 (Tlr4) and impaired hippocampus-dependent performance in the marble test. However, the 12-month-old female mice became obese. Control diet KO mice exhibited impaired hippocampal-dependent behaviors, increased brain expression of the serotonin receptors Htr2c and Htr1b, as well as increased Tlr4 and mitochondrial regulator, peroxisome proliferator-activated receptor gamma-coactivator-1a (Ppargc1a). Paradoxically, these, and other changes, were reversed in KO-WD mutants, suggesting a complex interplay between Sert deficiency and metabolic factors as well as potential compensatory molecular mechanisms that might be disrupted by the WD exposure. Most, but not all, of the changes in gene expression in the brain and liver of KO mice were not exhibited by the HET mice fed with either diet. Some of the WD-induced changes were similar in the KO-WD and HET-WD-fed mice, but the latter displayed a “rescued” phenotype in terms of diet-induced abnormalities in glucose tolerance, neuroinflammation, and hippocampus-dependent performance. Thus, complete versus partial Sert inactivation in aged mice results in distinct metabolic, molecular, and behavioral consequences in response to the WD. Our findings show that Sert\(^{+/−}\) mice are resilient to certain environmental challenges and support the concept of heterosis as evolutionary adaptive mechanism.
KW  - Sert-deficient mice
KW  - Western diet
KW  - aging
KW  - glucose tolerance
KW  - Toll-like receptor 4 (TLR4)
KW  - serotonin receptors
KW  - obesity
KW  - heterosis
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-199813
SN  - 1662-453X
VL  - 14
ER  -