TY - JOUR T1 - Quantification of cerebral cannabinoid receptors subtype 1 (CB1) in healthy subjects and schizophrenia by the novel PET radioligand [<sup>11</sup>C]OMAR JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 331 LP - 331 VL - 51 IS - supplement 2 AU - Dean Wong AU - Hiroto Kuwabara AU - Andrew Horti AU - Vanessa Raymont AU - James Brasic AU - Maria Guevara AU - Ayon Nandi AU - Arman Rahmim AU - Jeffrey Ming AU - Nicola Cascella Y1 - 2010/05/01 UR - http://jnm.snmjournals.org/content/51/supplement_2/331.abstract N2 - 331 Objectives As a step towards developing in vivo imaging tracers for cannabinoid receptor subtype 1 (CB1) we present here our first human studies in both healthy control patients and patients with schizophrenia using the novel PET tracer, [11C]OMAR (JHU 75528). In this study [11C]OMAR will be used to investigate normal aging and the differences in the cannabinoid system of healthy controls vs. patients with schizophrenia. Methods We studied ten healthy controls and six patients with schizophrenia using high specific activity [11C]OMAR. CB1 binding was expressed as the distribution volume (VT). Results VT was the highest in the globus pallidus and the cortex in both controls and patients with schizophrenia. Within the controls, there was a significant negative correlation of [11C]OMAR binding (i.e, CB1 distribution) and age, most significantly in the globus pallidus. Amongst patients with schizophrenia, there was no significant decline with age. In fact, patients had an overall elevated binding which fell significantly outside the 95% prediction limits of the linear regression of VT vs. age (p = 0.003). There was also a significant correlation between VT in patients and the ratio of the BPRS (Brief Psychiatry Rating Score) psychosis to withdrawal subscores in frontal lobe (r2=0.61), cingulate gyrus (r2=0.60), parietal cortex (r2=0.64) and putamen (r2=0.58). Conclusions In conclusion, [11C] OMAR can image human CB1 receptors in normal aging and schizophrenia. Our initial data in schizophrenia subjects seem to suggest an association of elevated binding specific brain regions and symptoms of the disease. Research Support Sanofi-Aventis, NIH grants DA000412, MH07901 ER -