Receptor-like stereospecific binding of a pyrethroid insecticide to mouse brain membranes

A heterogeneous particulate fraction of mouse brain homogenates binds NRDC 157 (3-phenoxybenzyl [1 R , cis ]-3-(2,2-dibromovinyl)-2,2- dimethylcyclopropanecarboxylate), a potent pyrethroid insecticide, stereospecifically and with high affinity. Stereospecific binding is a minor component of total binding (2.8%); the remainder of observed binding is predominantly nonspecific and unsaturable. Stereospecific binding is half-saturated at 4×10 −8 M and fully saturated at concentrations in excess of 1×10 −7 M . The stereospecific binding capacity of this preparation was 200–250 pmoles of NRDC 157 per gram equivalent of brain tissue (2.3–2.8 pmol/mg protein). This binding site may represent the neural receptor involved in the stereospecific toxic action of pyrethroids.