Effects of SR 48692 on neurotensin-induced calcium-activated chloride currents in the Xenopus oocyte expression system: agonist-like activity on the levocabastine-sensitive neurotensin receptor and absence of antagonist effect on the levocabastine insensitive neurotensin receptor.

The effect of the drug SR 48692 on the Ca(2+)-activated Cl- current induced by neurotensin on Xenopus oocytes injected with cRNAs encoding rodent high and low affinity neurotensin receptors, was examined. In this receptor expression system, SR 48692 failed to antagonize electrophysiological measurement of neurotensin-evoked current via the rat high affinity neurotensin receptor, whereas its application onto oocytes expressing the mouse low affinity neurotensin receptor triggered an inward current, as well as neurotensin itself. However, no current activation was observed after application of the drug on oocytes expressing the rat high affinity neurotensin receptor. These observations in the oocyte expression system did not reflect typical antagonist properties of SR 48692 drug.