The MAM-E17 schizophrenia rat model: Comprehensive behavioral analysis of pre-pubertal, pubertal and adult rats

Hyperactive behavior in female rats in utero‐exposed to group B Streptococcus‐induced inflammation

“…Altogether, the increased locomotion in the EPM, in addition to increased number of open arms entries, suggest that behavioral alterations observed in GBS‐exposed females might be due to disinhibited behaviors – reflected by a loss of control of impulsivity associated with dangerous situation avoidance – rather than anxiety‐related impairments (Olausson et al, 2001; Soubrie et al, 1986; VanRyzin et al, 2016). Studies performed on MAM‐treated rats reported similar findings as ours in the EPM: a disinhibited behavior toward open arms’ exploration observed during prepuberty and adulthood, but not during late puberty (Du and Grace, 2013; Gastambide et al, 2015; Kállai et al, 2017). Increased exploration of open arms can also be the consequence of memory impairment, and not only disinhibited or anxiolytic behaviors (Gastambide et al, 2015; Kállai et al, 2017).…”

“…The lack of difference between GBS‐exposed male and female rats is possibility due to a lack of power (p = .14). The interpretation of the rotarod results is complex, as the subjects’ performance on the rotating rod is depending on many factors such as motor skills, motor adaptation and learning capability, and motivation to perform the task (Kállai et al, 2017). The rotarod is considered partly as a cerebellar‐dependent task aiming to evaluate motor skills including balance and motor coordination, in addition to motor learning by performing consecutive trials (Goddyn et al, 2006).…”

“…Studies using SH rats and High‐Active mice previously reported similar findings: adult SHR females exhibited increased spontaneous locomotor activities compared to SHR males (Berger and Sagvolden, 1998; Bucci et al, 2008; Majdak et al, 2016). Moreover, increased locomotor activity has been previously reported in rats in utero ‐exposed to methyl azoxy‐methanol acetate (MAM), a rat model presenting schizophrenic‐like traits (Kállai et al, 2017). In the open field test, no difference during prepuberty (P28‐42) was detected in MAM‐treated rats, but increased spontaneous locomotion was observed during late puberty (P56‐70) and adulthood (P98‐112) (Hazane et al, 2009; Kállai et al, 2017).…”

“…Moreover, increased locomotor activity has been previously reported in rats in utero ‐exposed to methyl azoxy‐methanol acetate (MAM), a rat model presenting schizophrenic‐like traits (Kállai et al, 2017). In the open field test, no difference during prepuberty (P28‐42) was detected in MAM‐treated rats, but increased spontaneous locomotion was observed during late puberty (P56‐70) and adulthood (P98‐112) (Hazane et al, 2009; Kállai et al, 2017). Hyperactive spontaneous locomotion emerging post‐puberty (P60) was also reported in MAM‐exposed female rats when assessed in the open field test (Hazane et al, 2009).…”

“…Pups were counted and weighed daily from P1 to prevent any stressful situation by moving them on P0. Our behavioral experiments were carried out in three age‐periods: prepuberty (P15‐25; open field), late puberty (P30‐50; rotarod and elevated‐plus‐maze) and adulthood (P105‐110; elevated‐plus‐maze) (Kállai et al, 2017). Each rat offspring was not utilized for more than three distinct behavioral tests through lifespan.…”