Axonal tuning by GABA_(A) receptor unveils novel tricks from an old dog

In the last years,axonal conductance of action potential trains became a novel subject of study,changing the view of axons,from a static cable-like compartment to a more complex and dynamic system(Debanne et al.,2011).Axonal computation,indeed,is canonically constituted by the action of voltage-gated ion channels,such as the classic Na+and K+channels,but recent studies demonstrated that it can be modulated by the action of other ion channel pumps,and metabolic factors(Byczkowicz et al.,2019;Zang and Marder.

Schwann cell development,maturation and regeneration：a focus on classic and emerging intracellular signaling pathways

The development,maturation and regeneration of Schwann cells（SCs）,the main glial cells of the peripheral nervous system,require the coordinate and complementary interaction among several factors,signals and intracellular pathways.These regulatory molecules consist of integrins,neuregulins,growth factors,hormones,neurotransmitters,as well as entire intracellular pathways including protein-kinase A,C,Akt,Erk/MAPK,Hippo,mTOR,etc.For instance,Hippo pathway is overall involved in proliferation,apoptosis,regeneration and organ size control,being crucial in cancer proliferation process.In SCs,Hippo is linked to merlin and YAP/TAZ signaling and it seems to respond to mechanic/physical challenges.Recently,among factors regulating SCs,also the signaling intermediates Src tyrosine kinase and focal adhesion kinase（FAK）proved relevant for SC fate,participating in the regulation of adhesion,motility,migration and in vitro myelination.In SCs,the factors Src and FAK are regulated by the neuroactive steroid allopregnanolone,thus corroborating the importance of this steroid in the control of SC maturation.In this review,we illustrate some old and novel signaling pathways modulating SC biology and functions during the different developmental,mature and regenerative states