Spadin

Spadin is a potent TREK-1 channel inhibitor with IC50 of 71nM. It is a secreted peptide derived from the propeptide generated by the maturation of NTSR3/Sortilin. [1]

TREK-1, aka KCNK2, is a two-pore domain ion channel that involved in the passive transmembrane K+ transport. It is related to the ischemia, anesthesia and electrogenesis in the neurons. It also plays an important role in the pathophysiological process of depression and in the response to antidepressant. [1]

In TREK-1 transfected COS-7 cells, 100nM of spadin inhibited 63% of the TREK-1 current stimulated by arachidnice acid. Spadin also blocked the TREK-1 channels activity in CA3 hippocampal neurons on brain slices of wild-type mice. [1]

In behavioral tests that predicting an antidepressant response, spadin-treated mice displayed a resistance to depression. Mice treated with spadin for 4 days also exhibited a significant antidepressant effect as well as elevated hippocampal phosphorylation of CREB protein and neurogenesis. [2]

References:
1.  Borsotto M, Veyssiere J, Moha Ou Maati H et al. Targeting two-pore domain K(+) channels TREK-1 and TASK-3 for the treatment of depression: a new therapeutic concept. Br J Pharmacol. 2015 Feb;172(3):771-84.
2.  Mazella J, Pétrault O, Lucas G, et al. Spadin, a sortilin-derived peptide, targeting rodent TREK-1 channels: a new concept in the antidepressant drug design. PLoS Biol. 2010 Apr 13;8(4):e1000355.