PT  - JOURNAL ARTICLE
AU  - Daniela Schulz
AU  - Sudeepti Southekal
AU  - Sachin Junnarkar
AU  - Sri Harsha Maramraju
AU  - Wynne Schiffer
AU  - Srilalan Krishnamoorthy
AU  - Martin Purschke
AU  - Paul Vaska
AU  - Craig Woody
AU  - David  Schlyer
TI  - [11C]Raclopride kinetics in awake and anesthetized rats using the RatCAP awake rat brain PET
DP  - 2009 May 01
TA  - Journal of Nuclear Medicine
PG  - 1203--1203
VI  - 50
IP  - supplement 2
4099  - http://jnm.snmjournals.org/content/50/supplement_2/1203.short
4100  - http://jnm.snmjournals.org/content/50/supplement_2/1203.full
SO  - J Nucl Med2009 May 01; 50
AB  - 1203 Objectives The RatCAP scanner has been developed to enable conscious rat brain imaging without the effects of anesthesia. The objective of this study was to assess receptor availability awake and anesthetized using the bolus + infusion method with [11C]raclopride. Methods The bolus + infusion method is designed to maintain a steady-state condition and detect perturbations from equilibrium. Here, from 0.2 to 1.3 mCi (total mass below 5 nmole per kg) were administered to a rat wearing the RatCAP with some intervention. In separate experiments, blood samples were taken to asses the level of stress hormones in the rats while in the RatCAP. Results With a suitable infusion rate, this method results in a reliable steady state plateau in the striatum. As one intervention, a bolus injection of 2 mg/kg of cold raclopride at 20 minutes after the start of the study displaced [11C]raclopride from the striatum. The clearance rate of the radiotracer from the receptors was slower in anesthetized than in the unanesthetized rat which is consistent with results obtained previously in unanesthetized rats. Stress hormone levels showed a decrease after 1 hour in the RatCAP. Results from chemical and behavioral interventions to alter dopamine levels will be presented. Conclusions Imaging using the RatCAP scanner in the awake, freely moving animal reveals differences between the awake and anesthetized states. The decrease in stress hormone levels indicates acclimation to the RatCAP over a time period of about one hour. Research Support This work was supported by the U.S. Department of Energy (OBER) under Prime Contract No. DE-AC02-98CH10886.