[11C]Raclopride binding in the striatum of minimally restrained and free-walking awake mice in a positron emission tomography study

ABSTRACT Anesthesia and restraint stress have profound impacts on brain functions, including neural activity and cerebrovascular function, possibly influencing functional and neurochemical positron emission tomography (PET) imaging data. For circumventing this effect, we developed an experimental system enabling PET imaging of free‐walking awake mice with minimal restraints by fixing the head to a holder. The applicability of this system was investigated by performing PET imaging of D2 dopamine receptors with [11C]raclopride under the following three different conditions: (1) free‐walking awake state; (2) 1.5% isoflurane anesthesia; and (3) whole‐body restraint without anesthesia. [11C]raclopride binding potential (BPND) values under isoflurane anesthesia and restrained awake state were significantly lower than under free‐walking awake state (P