Early life stress effects on adult stress-induced corticosterone secretion and anxiety-like behavior in the C57BL/6 mouse are not as robust as initially thought

An overview of maternal separation effects on behavioural outcomes in mice: Evidence from a four-stage methodological systematic review

“…This raises the possibility that all findings obtained under traditional housing conditions will need to be reconsidered, because the implementation of environmental enrichment might skew conclusions from behavioural and biological analyses (Macri et al, 2013). the cycle in which the test will be run (Jensen Pena and Champagne, 2013;Parfitt et al, 2007;Toki et al, 2007). The stress-induced responses differ when MS occurs during the first period of the light cycle or during the last period (Parfitt et al, 2007).…”

“…the cycle in which the test will be run (Jensen Pena and Champagne, 2013;Parfitt et al, 2007;Toki et al, 2007). The stress-induced responses differ when MS occurs during the first period of the light cycle or during the last period (Parfitt et al, 2007). One possible explanation is that neuroendocrine hormone secretions are time-dependent, peaking and subsiding during distinct phases of the day to modulate different responses to stressinduced conditions (Malisch et al, 2008;Zimmermann and Critchlow, 1967).…”

“…A common argument from studies that use litter control is that litter size might affect the opportunity to feed and the degree of maternal care provided by the dam, which influence the animal's growth (Chahoud and Paumgartten, 2009;Grota and Ader, 1969;Prager et al, 2010;Rodel et al, 2010). On the other hand, some studies suggest that artificial methods not be used to control litter sizes (Fabricius et al, 2008;Parfitt et al, 2004;Parfitt et al, 2007;Romeo et al, 2003). These studies would rather assume the risks of litter size on the animal's development and avoid any manipulation of the pups.…”

“…According to Nylander and Roman (2013), the consequence of the variability in protocols is that there is no single 'rodent maternal separation model' but several separation models with different effects. Although separation models are not safe from criticism (Molet et al, 2014), a large body of ELS evidence indicates that postnatal manipulations are important models for investigating the early-life impact on depressive and anxiety-like behaviours (Andersen, 2015;Millstein and Holmes, 2007;Romeo et al, 2003;Schmidt et al, 2011;Vetulani, 2013), drug-seeking behaviours (Cruz et al, 2008;Garcia-Gutierrez et al, 2015;Huot et al, 2001;Kawakami et al, 2007;Nylander and Roman, 2013) and neuroendocrine stressinduced responses among rodents (Anisman et al, 1998;Kawakami et al, 2013;Loizzo et al, 2010;Parfitt et al, 2004;Parfitt et al, 2007). The evidence has provided reliable implications for face, construct and predictive validity for MS rodent studies (Plotsky et al, 2005;Schmidt et al, 2011).…”

Serotonin deficiency alters susceptibility to the long-term consequences of adverse early life experience

“…Indeed, multiple studies have reported significant long-term effects of repeated MS in rodents (Huot et al, 2001, Romeo et al, 2003, Plotsky et al, 2005, Murgatroyd et al, 2009), whereas other studies have found minimal or no phenotypes following MS (Millstein and Holmes, 2007, Parfitt et al, 2007). Novel paradigms combining MS with early weaning (Carlyle et al, 2012) or unpredictable mild maternal stress (Franklin et al, 2011) appear to be more robust, but additional models are warranted.…”