title: [123I]IBZM SPET analysis of dopamine D2 receptor occupancy in narcoleptic patients in the course of treatment.
abstract: Elevated levels of central D2 dopamine receptors were found on postmortem examination in cases of human narcolepsy. In vivo investigations using positron emission tomography (PET) and single photon emission tomography (SPET) found no changes of D2 binding in the striatal structures. To investigate whether the elevated D2 receptors in postmortem investigations are due to long-term treatment effects, we applied 123I-labeled (S)-2-hydroxy-3-iodo-6-methoxy-([1-ethyl-2-pyrrolidinyl]methyl) benzamide (IBZM) ([123I]IBZM, a highly selective CNS D2 dopamine receptor ligand) and SPET in narcoleptic patients in the course of treatment with stimulants and/or antidepressants. Before treatment we found no changes in D2 binding in 10 patients (in comparison to 10 normal controls). After treatment (performed in five patients for 3 months) we found changes in D2 binding in four of them, indicating that the results of the postmortem studies could have been influenced by long-term medications. Human narcolepsy seems not to be related to a striatal D2 dopaminergic disturbance.
authors.affiliation: Department of Psychiatry, Georg August University, Goettingen, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Staedt
authors.forename: G
authors.initials: G
authors.lastname: Stoppe
authors.forename: A
authors.initials: A
authors.lastname: Kögler
authors.forename: H
authors.initials: H
authors.lastname: Riemann
authors.forename: G
authors.initials: G
authors.lastname: Hajak
authors.forename: A
authors.initials: A
authors.lastname: Rodenbeck
authors.forename: G
authors.initials: G
authors.lastname: Mayer
authors.forename: B J
authors.initials: BJ
authors.lastname: Steinhoff
authors.forename: D L
authors.initials: DL
authors.lastname: Munz
authors.forename: D
authors.initials: D
authors.lastname: Emrich
authors.forename: E
authors.initials: E
authors.lastname: Rüther
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000928:Antidepressive Agents / Q000627:therapeutic use; D001549:Benzamides; D016022:Case-Control Studies; D018492:Dopamine Antagonists; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D009290:Narcolepsy / Q000188:drug therapy / Q000378:metabolism*; D011759:Pyrrolidines; D011954:Receptors, Dopamine / Q000187:drug effects*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
chemical_list: D000928:Antidepressive Agents; D001549:Benzamides; D018492:Dopamine Antagonists; D007457:Iodine Radioisotopes; D011759:Pyrrolidines; D011954:Receptors, Dopamine; C055743:3-iodo-2-hydroxy-6-methoxy-N-((1-ethyl-2-pyrrolidinyl)methyl)benzamide