The quantitative [14C]-2-deoxy-D-glucose autoradiographic method was used to compare the acute effects of the Ca2+ channel antagonist nimodipine (10 mg/kg) and the Ca2+ channel activator Bay K 8644 (1.25 mg/kg) on local cerebral glucose utilization of rat brain after single, intraperitoneal application. Nimodipine reduced glucose metabolism significantly in 23 of the 49 brain regions evaluated. Bay K 8644 decreased the local cerebral glucose utilization to an even greater extent in all regions studied. The anatomic localization of those regions with the largest decrease of glucose utilization was almost identical for both drugs (globus pallidus, hippocampus, geniculate body, substantia nigra, and entorhinal cortex). No increase in glucose metabolism was measured in any of the brain areas evaluated.