In rat striatal slices, the increase (114 +/- 11%) in K(+)-evoked [3H]dopamine release induced by neurotensin (10 nM) was antagonized by 2-[(1-(7-chloro-4-quinolinyl)-5-(2,6-dimethoxyphenyl)pyrazol-3-yl) carboxylamino]tricyclo(3.3.1.1.3.7)decan-2-carboxylic acid (SR 48692, IC50 = 1.2 +/- 0.11 nM). SR 48692 (100 nM) also suppressed the neurotensin (10 nM)-induced increase (47%) in K(+)-evoked [3H]dopamine release in primary cultures of fetal rat mesencephalic cells. These results further characterize SR 48692 as a potent antagonist of neurotensin receptors in the rat.