The association between serotonin transporter availability and the neural correlates of fear bradycardia.
Proc Natl Acad Sci U S A
; 116(51): 25941-25947, 2019 12 17.
Article
em En
| MEDLINE
| ID: mdl-31772023
ABSTRACT
Susceptibility to stress-related psychopathology is associated with reduced expression of the serotonin transporter (5-HTT), particularly in combination with stress exposure. Aberrant physiological and neuronal responses to threat may underlie this increased vulnerability. Here, implementing a cross-species approach, we investigated the association between 5-HTT expression and the neural correlates of fear bradycardia, a defensive response linked to vigilance and action preparation. We tested this during threat anticipation induced by a well-established fear conditioning paradigm applied in both humans and rodents. In humans, we studied the effect of the common 5-HTT-linked polymorphic region (5-HTTLPR) on bradycardia and neural responses to anticipatory threat during functional magnetic resonance imaging scanning in healthy volunteers (n = 104). Compared with homozygous long-allele carriers, the 5-HTTLPR short-allele carriers displayed an exaggerated bradycardic response to threat, overall reduced activation of the medial prefrontal cortex (mPFC), and increased threat-induced connectivity between the amygdala and periaqueductal gray (PAG), which statistically mediated the effect of the 5-HTTLPR genotype on bradycardia. In parallel, 5-HTT knockout (KO) rats also showed exaggerated threat-related bradycardia and behavioral freezing. Immunohistochemistry indicated overall reduced activity of glutamatergic neurons in the mPFC of KO rats and increased activity of central amygdala somatostatin-positive neurons, putatively projecting to the PAG, which-similarly to the human population-mediated the 5-HTT genotype's effect on freezing. Moreover, the ventrolateral PAG of KO rats displayed elevated overall activity and increased relative activation of CaMKII-expressing projection neurons. Our results provide a mechanistic explanation for previously reported associations between 5-HTT gene variance and a stress-sensitive phenotype.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Estresse Psicológico
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Bradicardia
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Reação de Congelamento Cataléptica
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Proteínas da Membrana Plasmática de Transporte de Serotonina
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Medo
Tipo de estudo:
Risk_factors_studies
Limite:
Adult
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Animals
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Humans
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Male
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Holanda