Exogenous l-dopa alters spiroperidol binding, in vivo, in the mouse striatum

The effect of exogenous l-dopa on the binding of tritiated spiroperidol, in vivo, in the murine striatum was investigated. The results obtained demonstrated that the binding of 3H-spiroperidol can be altered by the administration of l-dopa. This effect appears to be related to both the dose of spiroperidol and l-dopa given. Since l-dopa raised striatal dopamine levels in a dose dependent manner, these results suggest that the estimates of receptor parameters obtained using positron emission tomography and analogs of spiroperidol may be affected by the differences in endogenous dopamine concentrations among subjects.