Ls. Kegeles et Jj. Mann, IN-VIVO IMAGING OF NEUROTRANSMITTER SYSTEMS USING RADIOLABELED RECEPTOR LIGANDS, Neuropsychopharmacology, 17(5), 1997, pp. 293-307
In vivo functional brain imaging, including global blood flow, regiona
l cerebral blood flow (rCBF), measured with positron emission tomograp
hy (PET) and single photon emission computed tomography (SPECT), and r
egional cerebral metabolic rate (rCMR) measured with deoxyglucose PET,
have been widely used in studies of psychiatric disorders. These stud
ies have found modest differences and required large numbers of patien
ts. Activation studies using rCBF or rCMR as indices of neuronal activ
ity are more sensitive because patients act as their own control; howe
ver, findings localize regions of change but provide no data about spe
cific neurotransmitter systems. After a general discussion of the role
of neurotransmitter systems in neuropsychiatric disorders, an overvie
w of the methodology of development and selection of radioligands for
PET and SPECT is presented. Studies involving PET and SPECT ligand met
hods are reviewed and their findings summarized, including recent work
demonstrating successive mutual modulation of neurotransmitter system
s. Kinetic and equilibrium analysis modeling are reviewed. the emergin
g methodology of measuring neurotransmitter release on activation, bot
h pharmacologically and by task performance, using ligand methods is r
eviewed and proposed as a promising new approach for studying psychiat
ric disorders. (C) American College of Neuropsychopharmacology. Publis
hed by Elsevier Science Inc.