[Protective function of sigma-1 receptor in spinal cord motor neurons]

Sigma-1 receptor plays a protective function in various tissues. It was shown recently that a mutation in the sigma-1 receptor results in appearance of Amyotrophic Lateral Sclerosis (ALS). In the central nervous system (CNS) the highest amounts of sigma-1 receptor are found in motoneurons of the spinal cord, where receptor is localized in subsurface cisternae of cholinergic postsynaptic densities. The sigma-1 receptor is thought to regulate the ion channels activity and thus may influence neuron excitability. In this review we consider the possible pathways by which the sigma-1 receptor may reduce the excitability of motoneurons and thereby play a protective function during the progression of ALS.