Neurolepitcs induce a receptor-blocking effect at central dopaminergic neurons. This may be demonstrated in mice by inhibition of methylphenidate induced compulsive gnawing. In the post-receptor-blocking phase the receptor is temporarily hypersensitive to dopaminergic agonists like methylphenidate and apomorphine. By repeated dosage a competition is created between receptor-blockade and hypersensitivity, often in favour of the latter.