title: Reduced striatal dopaminergic innervation shown by IPT and SPECT in patients under neuroleptic treatment: need for levodopa therapy?
abstract: We investigated the availability of dopamine reuptake sites in the striata of two patients with productive symptoms and neuroleptic therapy as well as progressive parkinsonism using the new dopamine transporter ligand [123I]N-(3-iodopropen-2-yl)-2beta-carbo-methoxy-3beta- (4-chlorophenyl)tropane (IPT) and single photon emission computed tomography (SPECT). Normal specific binding in the caudate nucleus was 8.6 +/- 1.2 and in the putamen 6.5 +/- 1.3 (mean +/- S.D.; n = 8; mean age, 56.7 years; range 41-67 years). Patient 1 (age 43) was admitted to our clinic at age 38 because of left-sided parkinsonism. At age 40, she developed paranoid psychosis without change after cessation of L-DOPA and lisuride treatment for 3 months. She was diagnosed as a schizophrenic, paranoid subtype (DSM-III-R). IPT-SPECT showed a loss of dopaminergic nerve terminals (right caudate/putamen, 5.16/2.0; left caudate/putamen, 5.92/2.66). Patient 2 (age, 61 years) had a history of paranoid psychosis for approx. 30 years. He experienced progressive right-sided parkinsonism since age 57 when treated with clozapine. IPT-SPECT showed a marked reduction of striatal dopamine transporter binding (right caudate/putamen, 5.06/1.65; left caudate/putamen, 3.8/1.12). Our findings indicate that patients may suffer contemporaneously from Parkinson's disease and schizophrenia. In these patients, the proof of a nigrostriatal dopaminergic deficit justifies treatment with neuroleptics and dopaminergic drugs. Imaging of dopamine transporters with SPECT and IPT or a related compound represents an attractive alternative to the more complex measurements of fluorodopa uptake with positron emission tomography (PET).
authors.affiliation: Department of Neurology, Klinikum Grosshadern, Ludwig-Maximilians-University Munich, Germany. johannes.schwarz@medizin.uni-ulm.de
authors.forename: J
authors.initials: J
authors.lastname: Schwarz
authors.forename: J
authors.initials: J
authors.lastname: Scherer
authors.forename: C
authors.initials: C
authors.lastname: Trenkwalder
authors.forename: P D
authors.initials: PD
authors.lastname: Mozley
authors.forename: K
authors.initials: K
authors.lastname: Tatsch
mesh_terms: D000328:Adult; D000368:Aged; D014150:Antipsychotic Agents / Q000494:pharmacology*; D002421:Caudate Nucleus / Q000000981:diagnostic imaging / Q000187:drug effects; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D017072:Neostriatum / Q000000981:diagnostic imaging* / Q000187:drug effects; D010300:Parkinson Disease / Q000000981:diagnostic imaging*; D011699:Putamen / Q000000981:diagnostic imaging / Q000187:drug effects; D012563:Schizophrenia, Paranoid / Q000000981:diagnostic imaging* / Q000188:drug therapy; D015899:Tomography, Emission-Computed, Single-Photon; D014326:Tropanes
chemical_list: D014150:Antipsychotic Agents; D007457:Iodine Radioisotopes; D014326:Tropanes; C087210:N-(3-iodopropen-1-yl)-2-carbomethoxy-3-(4-chlorophenyl)tropane; D004298:Dopamine