Awake Nonhuman Primate Brain PET Imaging with Minimal Head Restraint: Evaluation of GABAA-Benzodiazepine Binding with 11C-Flumazenil in Awake and Anesthetized Animals

• DOI: 10.2967/jnumed.113.122077
• Publication Date: 2013-10-11T14:55:03Z
• Authors: Christine M. Sand...; Xiao Jin; Tim Mulnix; Krista Fowles; David Labaree; Jim Ropchan; Yiyun Huang; Kelly Cosgrove; Stacy A. Castner; Graham V. Williams; Lisa Wells; Eugenii A. Rabiner; Richard E. Carson
• Keywords: Flumazenil

Neuroreceptor imaging in the nonhuman primate (NHP) is valuable for translational research approaches humans. However, most NHP studies are conducted under anesthesia, which affects interpretability of receptor binding measures. The aims this study were to develop awake with minimal head restraint and compare vivo γ-aminobutyric acid type A (GABA_A)-benzodiazepine radiotracer ¹¹C-flumazenil anesthetized conditions. We hypothesized that potential (<i>BP</i>_ND) would be higher isoflurane-anesthetized monkeys. <b>Methods:</b> small animal PET scanner was fitted a mechanical device raised tilted 45° while back 35° custom chair optimal brain positioning, required acclimation animals chair, touch-screen tasks, intravenous catheter insertion, tilting. For studies, bolus–plus–constant infusion method used administration. Two rhesus monkeys scanned (<i>n =</i> 6 scans) 4 An infrared camera track motion during scans. Under condition, emission motion-tracking data acquired 40–75 min after injection. Anesthetized 90 min. Cortisol measurements Equilibrium analysis both (<i>n</i> = 4) 5) datasets compute mean <i>BP</i>_ND images template space, using pons as reference region. percentage change per minute radioactivity concentration calculated high- low-binding regions assess quality equilibrium. <b>Results:</b> acclimated procedures necessary perform imaging. Image comparable between relationship values (awake) 0.94 (anesthetized) + 0.36 (<i>r</i>² 0.95). levels significantly condition (<i>P</i> &lt; 0.05). <b>Conclusion:</b> successfully performed restraint. There close agreement