Environmental enrichment has no effect on the development of dopaminergic and GABAergic fibers during methylphenidate treatment of early traumatized gerbils

Abstract

It is widely believed, that environmental factors play a crucial role in the etiology and outcome of psychiatric diseases such as Attention-Deficit/Hyperactivity Disorder (ADHD). A former study from our laboratory has shown that both methylphenidate (MP) and handling have a positive effect on the dopaminergic fiber density in the prefrontal cortex (PFC) of early traumatized gerbils (Meriones unguiculatus). The current study was performed to investigate if enriched environment during MP application has an additional influence on the dopaminergic and GABAergic fiber densities in the PFC and amygdala in this animal model. Animals received a single early dose of methamphetamine (MA; 50 mg/kg; i.p.) on postnatal day (PD) 14, which is known to cause multiple changes in the subsequent development of several neurotransmitter systems including the dopaminergic systems, and were then treated with oral daily applications of MP (5 mg/kg) from PD30-60. Animals treated this way were either transferred to an enriched environment after weaning (on PD30) or were kept under impoverished rearing conditions.There was no effect of an enriched environment on the dopaminergic or GABAergic fiber density neither in the PFC nor in the amygdala. With regard to former studies these results underline the particular impact of MP in the treatment of ADHD.

Resilience priming: Translational models for understanding resiliency and adaptation to early life adversity

“…This remediating benefit of environmental stimulation also extends to animal models of neonatal brain injury (Gibb, Gonzalez, & Kolb, 2014;Komitova et al, 2013;Schuch et al, 2016;Schwartz, 1964), fetal alcohol syndrome (Rema & Ebner, 1999) and exposure to antiadrenergic hypertensive drugs (Ryan & Pappas, 1990), inflammatory mimetics (Kentner, Khoury, Lima Queiroz, & MacRae, 2016), and maternal physical stress (Laviola et al, 2004;Morley-Fletcher, Rea, Maccari, & Laviola, 2003). However, its success in reversing the effects of ELS are not universal (when animals are placed into EE in later life), nor are its benefits robust for all measures (Brummelte, Grund, Moll, Teuchert-Noodt, & Dawirs, 2008;Buschert et al, 2016;Kentner et al, 2016;Mychasiuk et al, 2014). This suggests that earlier exposure to EE may be more effective due to a time-dependent factor (e.g.…”

The Scutellaria Flavone, Oroxylin A, Improves Attention-Deficit/Hyperactivity Disorder Related Behaviors in Spontaneously Hypertensive Rats

“…The GABAergic and dopaminergic systems exhibit a high interconnectivity, with dopamine innervating GABAergic cell bodies, dendrites and axon terminals in either an excitatory or inhibitory manner (Brummelte et al, 2008) The psychostimulants methylphenidate and amphetamine are the drugs of choice for ADHD, providing clinical benefits against the three core symptoms in 70-80% of patients (Elia et al, 1999). But, occasional marked side effects including loss of appetite, insomnia and, less commonly, motor tics and rebound symptoms following rapid drug withdrawal make the development of alternative medication desirable (Kollins et al, 2001).…”