D2-receptor occupancy related to neuroleptical doses, side effects and prolactin levels: a study with IBZM-SPECT
摘要
D2-dopamine receptor binding in vivo can be investigated with 123-iodobenzamide (IBZM), an iodine-labelled dopamine receptor antagonist which is used to visualize brain D2 receptors in humans with single photon emission computed tomography (SPECT). A semiquantitative determination of D2 receptor binding is provided by the calculation of the ratio: striatal versus frontal binding (ST/FC ratio). This semiquantitative approach is most widely used in IBZM-studies (for review see Schloesser and Schlegel, 1995) since the radioactivity in the frontal cortex represents non-specific binding plus free IBZM, while that in the striatum also represents specific binding. By the application of the ST/FC ratio the following questions were investigated: (1) D2-receptor occupancy (RO) under treatment with typical (TN) and atypical neuroleptics (AN). (2) RO in relationship to mean daily dose/kg body weight, corrected for chlorpromazine equivalents. (3) RO in relationship to mean dayly dose/kg body weight, corrected for receptor affinity. (4) RO in relationship to extrapyramidal symptoms (EPS). (5) RO in relationship to prolactin plasma levels.