RT Journal Article
SR Electronic
T1 [11C]Raclopride kinetics in awake and anesthetized rats using the RatCAP awake rat brain PET
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1203
OP 1203
VO 50
IS supplement 2
A1 Daniela Schulz
A1 Sudeepti Southekal
A1 Sachin Junnarkar
A1 Sri Harsha Maramraju
A1 Wynne Schiffer
A1 Srilalan Krishnamoorthy
A1 Martin Purschke
A1 Paul Vaska
A1 Craig Woody
A1 David  Schlyer
YR 2009
UL http://jnm.snmjournals.org/content/50/supplement_2/1203.abstract
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.