Details

Autor(en) / Beteiligte

• Caravaggio, Fernando
• Porco, Natasha
• Kim, Julia
• Torres‐Carmona, Edgardo
• Brown, Eric
• Iwata, Yusuke
• Nakajima, Shinichiro
• Gerretsen, Philip
• Remington, Gary
• Graff‐Guerrero, Ariel

Titel

Measuring amphetamine‐induced dopamine release in humans: A comparative meta‐analysis of [11C]‐raclopride and [11C]‐(+)‐PHNO studies

Ist Teil von

• Synapse (New York, N.Y.), 2021-05, Vol.75 (5), p.e22195-n/a

Ort / Verlag

United States: Wiley Subscription Services, Inc

Erscheinungsjahr

2021

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• The radiotracers [11C]‐raclopride and [11C]‐(+)‐PHNO are commonly used to measure differences in amphetamine‐induced dopamine release between healthy persons and persons with neuropsychiatric diseases. As an agonist radiotracer, [11C]‐(+)‐PHNO should theoretically be roughly 2.7 times more sensitive to displacement by endogenous dopamine than [11C]raclopride. To date, only one study has been published comparing the sensitivity of these two radiotracers to amphetamine‐induced dopamine release in healthy persons. Unfortunately, conflicting findings in the literature suggests that the dose of amphetamine they employed (0.3 mg/kg, p.o.) may not reliably reduce [11C]‐raclopride binding in the caudate. Thus, it is unclear whether the preponderance of evidence supports the theory that [11C]‐(+)‐PHNO is more sensitive to displacement by amphetamine in humans than [11C]‐raclopride. In order to clarify these issues, we conducted a comparative meta‐analysis summarizing the effects of amphetamine on [11C]‐raclopride and [11C]‐(+)‐PHNO binding in healthy humans. Our analysis indicates that amphetamine given at 0.3 mg/kg, p.o. does not reliably reduce [11C]‐raclopride binding in the caudate. Second, the greater sensitivity of [11C]‐(+)‐PHNO is evidenced at 0.5 mg/kg, p.o., but not at lower doses of amphetamine. Third, our analysis suggests that [11C]‐(+)‐PHNO may be roughly 1.5 to 2.5 times more sensitive to displacement by amphetamine than [11C]‐raclopride in healthy persons. We recommend that future displacement studies with these radiotracers employ 0.5 mg/kg, p.o. of amphetamine with a dose, post‐scan interval of at least 3 hr. Using this dose of amphetamine, [11C]‐raclopride studies should employ at least n = 34 participants per group, while [11C]‐(+)‐PHNO studies should employ at least n = 6 participants per group, in order to be sufficiently powered (80%) to detect changes in radiotracer binding within the caudate. Our meta‐analysis suggests that the agonist radiotracer [11C]‐(+)‐PHNO is 1.5 to 2.5 times more sensitive to displacement by amphetamine than [11C]‐raclopride in healthy persons. We recommend that future displacement studies with these radiotracers use 0.5 mg/kg, p.o. of amphetamine.