The synthesis and structure activity relationship (SAR) study of a novel se
ries of N-type calcium channel blockers are described. L-Cysteine derivativ
e 2a was found to be a potent and selective N-type calcium channel blocker
with IC50 0.63 muM on IMR-32 assay. Compound 2a showed analgesic efficacy i
n the rat formalin-induced pain model by intrathecal and oral administratio
n. (C) 2001 Elsevier Science Ltd. All rights reserved.