Dyskinetic animals had lower levels of cAMP/cGMP during the increasing phase of dyskinesias than eukinetic animals, but their levels increased in the extinction phase of dyskinesiasBoth dyskinesias and the abnormal lowering of striatal cAMP/cGMP could be prevented by amantadineTotal cGMP‐specific PDE activity was increased in dyskinetic animalsAfter l‐dopa, PDE1B and PDE10A expression did not increase and, accordingly, PDE1B and PDE10A inhibitors failed to prevent dyskinesias. The gene discussed is PDE10A; the disease is Dyskinesia.