Maternal separation increases pain sensitivity by reducing the activity of serotonergic neurons in the dorsal raphe nucleus and noradrenergic neurons in locus coeruleus.

Autor: Vilela FC; Instituto de Ciências Biomédicas, Universidade Federal de Alfenas (Unifal-MG), Alfenas, Brazil. Electronic address: facvilela@gmail.com., Vieira JS; Instituto de Ciências Biomédicas, Universidade Federal de Alfenas (Unifal-MG), Alfenas, Brazil., Vitor-Vieira F; Instituto de Ciências Biomédicas, Universidade Federal de Alfenas (Unifal-MG), Alfenas, Brazil., Kalil-Cutti B; Instituto de Ciências Biomédicas, Universidade Federal de Alfenas (Unifal-MG), Alfenas, Brazil., da Silva JRT; Instituto de Ciências da Motricidade, Universidade Federal de Alfenas (Unifal-MG), Alfenas, Brazil., Giusti-Paiva A; Instituto de Ciências Biomédicas, Universidade Federal de Alfenas (Unifal-MG), Alfenas, Brazil., da Silva ML; Instituto de Ciências da Motricidade, Universidade Federal de Alfenas (Unifal-MG), Alfenas, Brazil.
Jazyk: angličtina
Zdroj: Neuroscience letters [Neurosci Lett] 2021 Mar 23; Vol. 748, pp. 135734. Date of Electronic Publication: 2021 Feb 14.
DOI: 10.1016/j.neulet.2021.135734
Abstrakt: Animals subjected to early life maternal separation exhibit increased sensitivity to chemical, thermal, and mechanical stimuli during adulthood. However, the mechanism by which maternal separation can alter pain sensitivity in adulthood has not yet been investigated. Thus, we aimed to evaluate the activity of serotonergic and noradrenergic neurons and the effect of serotonin (5-HT) and noradrenaline (NA) reuptake inhibitors in male and female Wistar rats subjected to maternal separation. This study consisted of two experiments: 1) to confirm whether maternal separation increased pain sensitivity (n = 8 per group) and to evaluate the activity of serotonergic neurons in the dorsal raphe nucleus and noradrenergic neurons in locus coeruleus in animals subjected to maternal separation in comparison to controls (n = 6 per group); and 2) to evaluate the effect of fluoxetine (a selective 5-HT reuptake inhibitor) and desipramine (a NA reuptake inhibitor) on sensitivity to chemical stimulation using formalin in animals subjected to maternal separation (n = 8 per group). Our findings indicated that maternal separation increases an animal's sensitivity to painful chemical stimulation and reduces the activity of 5-HT and NA neurons. In addition, acute pretreatment with a 5-HT or NA reuptake inhibitor prevented the increased response to painful stimulation induced by maternal separation. In conclusion, maternal separation increases pain sensitivity by reducing the activity of serotonergic neurons in the dorsal raphe nucleus and noradrenergic neurons in locus coeruleus. This study contributes to possible treatments for pain in individuals exposed to early life stress.
(Copyright © 2021 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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