Table of Contents
International Journal of Molecular Imaging
Volume 2011, Article ID 548123, 11 pages
http://dx.doi.org/10.1155/2011/548123
Research Article

Comparison of Cannabinoid CB1 Receptor Binding in Adolescent and Adult Rats: A Positron Emission Tomography Study Using [18F]MK-9470

1Schizophrenia Research Institute, Sydney, Australia
2ANSTO LifeSciences, ANSTO, PMB 1 Menai, Sydney, Australia
3School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
4Schizophrenia Research Laboratory, Neuroscience Research Australia, Randwick, NSW, Australia

Received 16 August 2011; Accepted 17 September 2011

Academic Editor: Guy Bormans

Copyright © 2011 Mathieu Verdurand et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Despite the important role of cannabinoid CB1 receptors (CB1R) in brain development, little is known about their status during adolescence, a critical period for both the development of psychosis and for initiation to substance abuse. In the present study, we assessed the ontogeny of CB1R in adolescent and adult rats in vivo using positron emission tomography with [18F]MK-9470. Analysis of covariance (ANCOVA) to control for body weight that would potentially influence [18F]MK-9470 values between the two groups revealed a main effect of age ( , ) on [18F]MK-9470 absolute binding (calculated as percentage of injected dose) with adult estimated marginal means being higher compared to adolescents amongst 11 brain regions. This finding was confirmed using in vitro autoradiography with [3H]CP55,940 ( , ). This ontogenetic pattern, suggesting increase of CB1R during the transition from adolescence to adulthood, is the opposite of most other neuroreceptor systems undergoing pruning during this period.