Interactions between cholinergic and fibroblast growth factor receptors in brain trophism and plasticity.

Acetylcholine, acting on both nicotinic receptors (nAChRs) and muscarinic receptors (mAChRs), plays a role in the regulation of synaptic plasticity, being involved in the regulation of cellular processes and cognitive functions, such as learning, memory and attention. Recently, G protein coupled receptors (GPCRs), including mAChRs, have been reported to transactivate tyrosine-kinase receptors (RTK), such as epidermal growth factor receptor (EGFR), and initiate their intracellular signaling. In this minireview we have first analysed the RTK transactivation mechanisms, involving cholinergic receptors, and thereafter the interplay between AChR and neurotrophic factor systems built up by FGF2 and fibroblast growth factor receptor 1 (FGFR1). Although mAChR and FGFR1 activate common signaling pathways, playing similar roles in the regulation of central nervous system (CNS) plasticity and trophism, this analysis revealed that at the present there are no data reporting an involvement of cholinergic receptors in the FGFR1 transactivation. However, here we reported preliminary results on FGFR1 transactivation by mAChRs, suggesting a possible interaction between mAChR and neurotrophic factor receptors, with potential relevance for cognitive functions.