It is described a new method to visualize the binding sites of the Ca(2+)-antagonist nimodipine (NIM) on brain cryostatic sections. NIM was bridged to colloidal gold sols by a suitable amphophilic detergent, and used according to autoradiographic procedures. A detailed mappage of vascular and neuronal NIM binding sites was allowed by silver-intensification of the NIM-gold complex bound to the nervous tissue. Selective distribution patterns were visualized in the main cerebral and cerebellar areas, suggesting that the drug potentially may act on multiple, different targets in the CNS.