Sulpiride receptor binding

The differential clinical actions of DA blockers on the DA receptor subtypes have not been defined with precision. Most neuroleptics appear to act at both D-1 and D-2 receptors. Some differences exist, however. The thioxanthenes bind to sites related to both DA receptor subtypes, but the butyrophenones seem to prefer sites assocaited with D-2 receptors, binding only weakly to those identified with D-1 receptors. Sulpiride, molindone and metoclopramide are relatively selective D-2 antagonists. 

In our model, we have indicated that atypical antipsychotics (12) (sulpiride, metoclopramide, molindone, and Ro 22-1319) differ from classical neuroleptics (tricyclics, butyrophenones, butaclamol, diphenyl-piperidines) by lacking a lipophilic functional group on the basic nitrogen that could extend into the auxiliary binding site identified in our model. The absence of this lipophilic functionality may now be stated to be the characteristic which distinguishes selective D-2 dopamine receptor antagonists from non-selective antagonists. 

---