Increased responsiveness of presumed 5-HT cells to citalopram in adult rats subjected to prolonged maternal separation relative to brief separation

Abstract

These findings suggest that early life stress gives rise to persistent changes in the function, but not the density or mRNA expression of central 5-HT(1A) receptors and/or 5-HT transporters.

Depressive behaviors and decreased expression of serotonin reuptake transporter in rats that experienced neonatal maternal separation

“…Previous reports suggested that neonatal maternal separation may decrease 5-HTergic activity of the raphe nucleus at adulthood (Gartside et al, 2003;Arborelius et al, 2004). In this study, we demonstrated that mRNA expression of serotonin reuptake transporter (5-HTT) in the raphe nucleus of adult rat is decreased by experience of neonatal maternal separation.…”

“…5-HT neurotransmission in the hippocampus is believed to be involved in the regulation of HPA axis activity throughout life. Indeed, it has been reported that periodic maternal separations during pre-weaning period result in persistent alterations in 5-HT concentrations (Matthews et al, 2001) and www.elsevier.com/locate/neures Neuroscience Research 58 (2007) [32][33][34][35][36][37][38][39] 5-HTergic functions in selective brain regions including the hippocampus (Gartside et al, 2003;Arborelius et al, 2004;Van Riel et al, 2004). Furthermore, stress response of adrenocorticotrophic hormone (ACTH) was blunted concomitantly with increased 5-HT turnover in the hippocampus in rats with neonatal maternal separation (Daniels et al, 2004).…”

Genetic variation in cortico-amygdala serotonin function and risk for stress-related disease

“…It is worth pointing out, therefore, that stress exposure likely impacts this mechanism via changes in 5-HT1A-R expression and function in the hippocampus. An increase in hippocampal 5-HT1A-R binding or mRNA is seen in rodents exposed to glucocorticoids, unpredictable stress, amygdalakindling, and, in some studies at least, maternal separation (Arborelius et al, 2004;Harvey et al, 2003;Kalynchuk et al, 2006;Lopez et al, 1999;Neumaier et al, 2002;Vazquez et al, 2000Vazquez et al, , 2002.…”

“…However, despite one study reporting no gross alteration in SERT-mediated reuptake in the rat forebrain under acute stress (Martin et al, 2000), and evidence of decreased DRN SERT mRNA in chronically socially stressed rats (McKittrick et al, 2000) (cf. Arborelius et al, 2004;Vazquez et al, 2000) it is not fully clear how SERT function is altered by stress. Notwithstanding, alterations in SERT-mediated reuptake would be predicted to be an important mechanism by which the serotonin system can self-regulate the amount of synaptic serotonin evoked by stress.…”

“…In this regard, a loss in mPFC 5-HT1A-R binding following stress or glucocorticoid excess (Crayton et al, 1996;Preece et al, 2004) (cf. Arborelius et al, 2004) could significantly impact this form of regulation.…”