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Further in vivo characterization of [ 11 C]‐(+)‐PHNO uptake into a retina‐like region of interest in humans
Author(s) -
Caravaggio Fernando,
Worhunsky Patrick,
GraffGuerrero Ariel,
Matuskey David
Publication year - 2020
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/syn.22135
Subject(s) - retina , in vivo , dopamine , biology , chemistry , medicine , neuroscience , genetics
The neurotransmitter dopamine is present in the retina and is involved in several modulatory functions. Unlike in rodents, dopamine D 3 receptors are expressed in the retina of humans. Recently, uptake of the D 3 receptor‐preferring radiotracer [ 11 C]‐(+)‐PHNO has been observed in a retina‐like region of interest (ROI) in humans. Here, we attempted to quantify [ 11 C]‐(+)‐PHNO uptake into this ROI using an independent sample, employing an extended scan acquisition time (120 min) and arterial kinetic modeling. Data from 14 healthy controls were analyzed (Mean Age: 38.41 ± 9.55, 3 female), 8 of which provided arterial line input function data (Mean Age: 41.07 ± 7.82, 3 female). Using Ichise's multilinear analysis (MA1) method, it was possible to quantify the volume of distribution ( V T ) of [ 11 C]‐(+)‐PHNO in this retina‐like region (Mean V T = 13.56 ± 3.52; Mean χ 2 = 2.08 ± 2.20). Notably, the shape of the time activity curve resembled closely that of the globus pallidus. Moreover, the V T values in the retina correlated well with binding potential ( BP ND ) values calculated using the simplified reference tissue model (Mean BP ND = 2.11 ± .94; Mean χ 2 = 5.76 ± 2.56), employing the cerebellum as the reference region ( r = .76, r 2 = .58). In summary, we provide evidence that the in vivo uptake of [ 11 C]‐(+)‐PHNO into a retina‐like ROI in humans can be quantified using both arterial blood sampling ( V T ) and simplified reference tissue methods ( BP ND ).