1 Department of Psychiatry, McGill University, Montreal, QC, Canada.
2 Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada.
3 Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada.
4 Institute of Mental Health Research, Affiliated with the University of Ottawa, Ottawa, ON, Canada.
5 Yale PET Center, Yale University, New Haven, CT, USA.
6 School of Psychoeducation, Université de Montréal, Montreal, QC, Canada.
7 CHU Ste-Justine Research Center, Montreal, QC, Canada.
8 Department of Psychology, Université Laval, Quebec, QC, Canada.
9 Department of Psychology, McGill University, Montreal, QC, Canada.
10 Department of Social and Preventative Medicine, Université de Montréal, Montreal, QC, Canada.
11 Department of Pediatrics and Psychology, Université de Montréal, Montreal, QC, Canada.
12 School of Public Health, University College Dublin, Belfield, Dublin, Ireland.
13 Department of Psychiatry and Addictology, Université de Montréal, Montreal, QC, Canada.
14 Department of Psychiatry, McGill University, Montreal, QC, Canada. marco.leyton@mcgill.ca.
15 Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada. marco.leyton@mcgill.ca.
16 Department of Psychology, McGill University, Montreal, QC, Canada. marco.leyton@mcgill.ca.
17 Center for Studies in Behavioral Neurobiology, Concordia University, Montreal, QC, Canada. marco.leyton@mcgill.ca.

mGlu5 receptor availability in youth at risk for addictions: effects of vulnerability traits and cannabis use.

Neuropsychopharmacology. 2020 May 15;:

Authors: Cox SML, Tippler M, Jaworska N, Smart K, Castellanos-Ryan N, Durand F, Allard D, Benkelfat C, Parent S, Dagher A, Vitaro F, Boivin M, Pihl RO, Côté S, Tremblay RE, Séguin JR, Leyton M

Abstract

The excitatory neurotransmitter glutamate has been implicated in experience-dependent neuroplasticity and drug-seeking behaviors. Type 5 metabotropic glutamate (mGlu5) receptors might be particularly important. They are critically involved in synaptic plasticity and their availability has been reported to be lower in people with alcohol, tobacco, and cocaine use disorders. Since these reductions could reflect effects of drug use or pre-existing traits, we used positron emission tomography to measure mGlu5 receptor availability in young adults at elevated risk for addictions. Fifty-nine participants (age 18.5±0.6) were recruited from a longitudinal study that has followed them since birth. Based on externalizing traits that predict future substance use problems, half were at low risk, half were at high risk. Cannabis use histories varied markedly and participants were divided into three subgroups: zero, low, and high use. Compared to low risk volunteers, those at elevated risk had lower [11C]ABP688 binding potential (BPND) values in the striatum, amygdala, insula, and orbitofrontal cortex (OFC). Cannabis use by risk group interactions were observed in the striatum and OFC. In these regions, low [11C]ABP688 BPND values were only seen in the high risk group that used high quantities of cannabis. When these high risk, high cannabis use individuals were compared to all other participants, [11C]ABP688 BPND values were lower in the striatum, OFC, and insula. Together, the study provides evidence that mGlu5 receptor availability is low in youth at elevated risk for addictions, particularly those who frequently use cannabis.

PMID: 32413893 [PubMed - as supplied by publisher]