Table 1. PET studies of dopaminergic function in non-human primates after ketamine administration compared to control.

Dopamine system studied	Study	Ketamine	Ketamine dose and route of administration	State of animal	Duration of treatment	When the outcome investigated	Ligand	Radiotracer administration	Study design/ control group	Analytical method	Region of interest	Na	Outcome measure	Change in dopamine measure after ketamine infusion compared to control condition
Dopamine synthesis	Tsukada et al.36	Racemic	3 and 10 mg kg−1 h−1, i.v	Anaesthetised	Infusion throughout scan	30 mins prior to scan	L-[ β -11C]DOPA	i.v	Within/ saline	Graphical analysis (L-[ β -11C]DOPA)	Str	4	Dopamine synthesis rate	↑
Dopamine release	Hashimoto et al., 201738	R and S-ketamine	0.5 mg kg−1	Sub-anaesthetised	Infusion 40 mins	After the end of infusion	[11C]raclopride	i.v	Saline	Reference tissue model	Caudate/putamen	4	Δ D2/3 receptor binding potentialb	↓29% (S-Ketamine)
														↔ No change (R Ketamine)
	Tsukada et al.36	Racemic	3 and 10 mg kg−1 h−1, i.v	Anaesthetised	Infusion throughout scan	30 mins prior to scan	[11C]raclopride	i.v	Within/ saline	Kinetic analysis ([11C]raclopride)	Str	4	Δ Binding potentialb	↓
Dopamine transporter	Tsukada et al.36	Racemic	3 and 10 mg kg−1 h−1, i.v	Anaesthetised	Infusion throughout scan	30 mins prior to scan	[11C]β-CFT	i.v	Within/ saline	Kinetic analysis ([11C]β-CFT)	Str	4	DAT binding potential	↓
	Yamamoto et al.34	Racemic	0.5 & 1.5 mg kg−1	Sub-anaesthetised	Infusion 40 mins	After the end of infusion	[11C]β-CFT	Bolus i.v	Within/ saline	Reference tissue model	Ct, Str, Midbrain, Thal	5	DAT binding potential	↔ No change
	Harada et al.40	Racemic	3 mg kg−1 h−1	Anaesthetised	Infusion throughout scan	60 mins before tracers	[11C]β-CFT & [11C]β-CIT-FE	i.v	Within/ saline	Kinetic analysis	Str	3	DAT binding potential	↓ ([11C]β-CFT)
														↔ No change ([11C]β-CIT-FE)
	Tsukada et al.39	Racemic	3 and 10 mg kg−1 h−1, i.v	Anaesthetised	Infusion throughout scan	60 mins before tracers	[11C]β-CFT & [11C]β-CIT-FE	i.v	Within/ saline	Kinetic analysis	Str	5	DAT binding potential	↓ (3 mg kg−1)

Abbreviations: Ct, cortex; DA, dopamine; DAT, dopamine transporter; i.m, intra muscular; i.v, intravenous; NA, not available; PET, positron emission tomography; Str, striatum; Thal, thalamus.

^aN the sample size represents the total number of animals used for the comparison in question.

^bGreater reduction in D2/D3 receptor binding potential after ketamine administration indicates greater dopamine release; ↑significant increase, ↓significant decrease and ↔no significant change.