Correlation of clinical response in apomorphine test with D2-receptor status as demonstrated by 123I IBZM-SPECT.
The knowledge of functional capacities of postsynaptic dopaminergic receptors in parkinsonian syndromes is important for differential diagnosis and for planning therapeutic approaches. Subcutaneous apomorphine challenges serve as a pharmacological tool in testing dopaminergic responsiveness, but discrepancies between results of the apomorphine test and long-term levodopa treatment remain. 123I IBZM (I-123 labeled iodobenzamide) as a dopaminergic receptor ligand allows depiction of D2-receptors by means of SPECT methods. The correlation between dopaminergic responsiveness and D2-receptor status as demonstrated by 123I IBZM-SPECT imaging was assessed by applying an apomorphine test to 41 patients with parkinsonian syndromes. All subsequently underwent an 123I IBZM-SPECT. Apomorphine responders showed a significantly higher binding of 123I IBZM than nonresponders, and patients with idiopathic Parkinson's disease (IPD) had higher D2-receptor density as visualized by SPECT than patients with other parkinsonian syndromes. The marked overlap between the groups allowed a reliable prediction only in patients with an abnormally low basal ganglia/frontal cortex ratio of 123I IBZM binding.
Schelosky
L
L
Department of Neurology, UKRV, Berlin, Germany.
Hierholzer
J
J
Wissel
J
J
Cordes
M
M
Poewe
W
W
D000328:Adult; D000368:Aged; D001058:Apomorphine / Q000378:metabolism; D001479:Basal Ganglia / Q000378:metabolism / Q000503:physiopathology*; D001549:Benzamides / Q000378:metabolism; D001665:Binding Sites / Q000502:physiology; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology; D003342:Corpus Striatum / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D011759:Pyrrolidines / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000378:metabolism / Q000502:physiology*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D001549:Benzamides; D011759:Pyrrolidines; D017448:Receptors, Dopamine D2; C055743:3-iodo-2-hydroxy-6-methoxy-N-((1-ethyl-2-pyrrolidinyl)methyl)benzamide; D001058:Apomorphine