NE-100, A NOVEL POTENT SIGMA-LIGAND, PREFERENTIALLY BINDS TO SIGMA(1) BINDING-SITES IN GUINEA-PIG BRAIN

The selectivity of N,N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]-ethylamine monohydrochloride (NE-100) for a, and sigma(2) binding sites was studied by means of binding of [H-3](+)-pentazocine and [H-3]1,3-di-o-tolylguanidine ([H-3]DTG) in guinea pig brain. NE-100 inhibited [H-3](+)-pentazocine binding to sigma(2) binding sites potently with an IC50 value of 1.54 +/- 0.26 nM while it had a weak effect on [H-3]DTG binding to sigma(2) binding sites. The inhibitory effect of NE-100 on [H-3](+)-pentazocine was 55 times more potent than that on [H-3]DTG binding. These results suggest that NE-100 is a potent and selective ligand for sigma(1) binding sites.