Impaired Ghrelin Signaling Does Not Lead to Alterations of Anxiety-like Behaviors in Adult Mice Chronically Exposed to THC during Adolescence

Abstract

As marijuana use during adolescence has been increasing, the need to understand the effects of its long-term use becomes crucial. Previous research suggested that marijuana consumption during adolescence increases the risk of developing mental illnesses, such as schizophrenia, depression, and anxiety. Ghrelin is a peptide produced primarily in the gut and is important for feeding behavior. Recent studies have shown that ghrelin and its receptor, the growth hormone secretagogue receptor (GHSR), play important roles in mediating stress, as well as anxiety and depression-like behaviors in animal models. Here, we investigated the effects of chronic tetrahydrocannabinol (THC) administration during late adolescence (P42–55) in GHSR (GHSR −/−) knockout mice and their wild-type littermates in relation to anxiety-like behaviors. We determined that continuous THC exposure during late adolescence did not lead to any significant alterations in the anxiety-like behaviors of adult mice, regardless of genotype, following a prolonged period of no exposure (1 month). These data indicate that in the presence of intact or impaired ghrelin/GHSR signaling, THC exposure during late adolescence has limited if any long-term impact on anxiety-like behaviors in mice.