The effect of long-term hindlimb unloading on the expression of risk neurogenes encoding elements of serotonin-, dopaminergic systems and apoptosis; comparison with the effect of actual spaceflight on mouse brain

Loss of physical contact in space alters the dopamine system in C. elegans

“…This supports rodent data reporting reduced DA synthesis, Comt-degradation, and D1R genes' expression during spaceflight (Popova et al, 2015). Interestingly, the hindlimb unloading rodent model (a commonly employed spaceflight ground analog) displays oppositely increased expression of dopaminergic genes including Comt and D1R (Kulikova et al, 2017). While counterintuitive, hindlimb unloading imposes mechanical stress on the forelimbs and tail, likely inducing a global mechanosensory dopaminergic response.…”

Sixty days of head-down tilt bed rest with or without artificial gravity do not affect the neuromuscular secretome

“…While exercise may increase GDNF expression, little is known about the impact of disuse. Kulikova et al [59] studied the expression of genes related to brain neuroplasticity, including GDNF, in mice after one month of hindlimb-suspension compared to mice that had spent one month on board Russian biosatellite Bion-M1. No changes in GDNF genes were found in the hindlimb-suspension group while the spaceflight group had decreased expressions of GDNF genes in the striatum and substantia nigra.…”

Hindlimb suspension-induced cell apoptosis in the posterior parietal cortex and lateral geniculate nucleus: corresponding changes in c-Fos protein and the PI3K/Akt signaling pathway

“…Based on results of a previous study (Jie et al 2015), it is possible that repression of the PI3K/ Akt signaling pathway contributes to the activation of cell apoptosis in the LGN. However, another study found no effet of hindlimb unloading on the expression of most genes, including apoptotic factors (Bcl-xl, Bax) (Kulikova et al 2017). These discrepant results may be due to evaluation of different genes and different brain regions.…”