The effects of fatty acid amide hydrolase inhibition and monoacylglycerol lipase inhibition on habit formation in mice

G, H.L. H, D. P, T. S, S.L. D, K. B, W.P. K, C.W. H, T.L. K. Disentangling the effects of Corticotrophin Releasing Factor and GABA release from the ventral bed nucleus of the stria terminalis on ethanol self-administration in mice

Excessive alcohol use causes a great deal of harm and negative health outcomes. Corticotrophin releasing factor (CRF), a stress-related neuropeptide, has been implicated in binge ethanol intake and ethanol dependence. CRF containing neurons in the bed nucleus of the stria terminalis (BNSTCRF) can control ethanol consumption. These BNSTCRF neurons also release GABA, raising the question, is it CRF or GABA release or both that is controlling alcohol consumption. Here, we used viral vectors to separate the effects of CRF and GABA release from BNSTCRF neurons on the escalation of ethanol intake in an operant self-administration paradigm in male and female mice. We found that CRF deletion in BNST neurons reduces ethanol intake in both sexes, with a stronger effect in males. For sucrose self-administration there was no effect of CRF deletion. Suppression of GABA release, via knockdown of vGAT, from BNSTCRF produced a transient increase in ethanol operant self-administration following in male mice, and reduced in motivation to work for sucrose on a progressive ratio schedule of reinforcement in a sex-dependent manner. Together, these results highlight how different signaling molecules from the same populations of neurons can bidirectionally control behavior. Moreover, they suggest that BNST CRF release is important for high intensity ethanol drinking that precedes dependence, whereas GABA release from these neurons may play a role in regulating motivation.

Molecular Landscape of Tourette's Disorder

Tourette's disorder (TD) is a highly heritable childhood-onset neurodevelopmental disorder and is caused by a complex interplay of multiple genetic and environmental factors. Yet, the molecular mechanisms underlying the disorder remain largely elusive. In this study, we used the available omics data to compile a list of TD candidate genes, and we subsequently conducted tissue/cell type specificity and functional enrichment analyses of this list. Using genomic data, we also investigated genetic sharing between TD and blood and cerebrospinal fluid (CSF) metabolite levels. Lastly, we built a molecular landscape of TD through integrating the results from these analyses with an extensive literature search to identify the interactions between the TD candidate genes/proteins and metabolites. We found evidence for an enriched expression of the TD candidate genes in four brain regions and the pituitary. The functional enrichment analyses implicated two pathways ('cAMP-mediated signaling' and 'Endocannabinoid Neuronal Synapse Pathway') and multiple biological functions related to brain development and synaptic transmission in TD etiology. Furthermore, we found genetic sharing between TD and the blood and CSF levels of 39 metabolites. The landscape of TD not only provides insights into the (altered) molecular processes that underlie the disease but, through the identification of potential drug targets (such as FLT3, NAALAD2, CX3CL1-CX3CR1, OPRM1, and HRH2), it also yields clues for developing novel TD treatments.

Patterns of Cannabis Use Among Individuals with Obsessive-Compulsive Disorder: Results from an Internet Survey

BACKGROUND

Americans increasingly use cannabis, including those with psychiatric disorders. Yet little is known about cannabis use among individuals with obsessive-compulsive disorder (OCD). Thus, we conducted the first survey of cannabis users with OCD.

METHODS

Adults with OCD (i.e., prior professional diagnosis and/or score above the cutoff on a validated scale) who reported using cannabis were recruited from internet sources to complete a survey querying demographic information, medical/psychiatric history, cannabis use patterns, and perceived cannabis effects.

RESULTS

Of 1096 survey completers, 601 met inclusion criteria. Inhalation/cannabis flower were the most common method/formulation participants endorsed; most identified using high-potency cannabis products; 42% met criteria for cannabis use disorder. Nearly 90% self-reported using cannabis medicinally, 33.8% had a physician's recommendation, and 29% used specifically to manage OCD symptoms. Most participants reported cannabis improved obsessions/compulsions; those with increased obsession severity perceived less benefit. Finally, most participants were not receiving evidence-based OCD treatment, and the odds of receiving treatment decreased with increased cannabis use.

CONCLUSIONS

In this survey, participants with OCD reported both subjective benefits and harms from cannabis use. Future research should clarify the risks and benefits of cannabis use to those with OCD and develop treatment models to better support this population.

Cannabinoid Modulation of Dopamine Release During Motivation, Periodic Reinforcement, Exploratory Behavior, Habit Formation, and Attention

Motivational and attentional processes energize action sequences to facilitate evolutionary competition and promote behavioral fitness. Decades of neuropharmacology, electrophysiology and electrochemistry research indicate that the mesocorticolimbic DA pathway modulates both motivation and attention. More recently, it was realized that mesocorticolimbic DA function is tightly regulated by the brain's endocannabinoid system and greatly influenced by exogenous cannabinoids-which have been harnessed by humanity for medicinal, ritualistic, and recreational uses for 12,000 years. Exogenous cannabinoids, like the primary psychoactive component of cannabis, delta-9-tetrahydrocannabinol, produce their effects by acting at binding sites for naturally occurring endocannabinoids. The brain's endocannabinoid system consists of two G-protein coupled receptors, endogenous lipid ligands for these receptor targets, and several synthetic and metabolic enzymes involved in their production and degradation. Emerging evidence indicates that the endocannabinoid 2-arachidonoylglycerol is necessary to observe concurrent increases in DA release and motivated behavior. And the historical pharmacology literature indicates a role for cannabinoid signaling in both motivational and attentional processes. While both types of behaviors have been scrutinized under manipulation by either DA or cannabinoid agents, there is considerably less insight into prospective interactions between these two important signaling systems. This review attempts to summate the relevance of cannabinoid modulation of DA release during operant tasks designed to investigate either motivational or attentional control of behavior. We first describe how cannabinoids influence DA release and goal-directed action under a variety of reinforcement contingencies. Then we consider the role that endocannabinoids might play in switching an animal's motivation from a goal-directed action to the search for an alternative outcome, in addition to the formation of long-term habits. Finally, dissociable features of attentional behavior using both the 5-choice serial reaction time task and the attentional set-shifting task are discussed along with their distinct influences by DA and cannabinoids. We end with discussing potential targets for further research regarding DA-cannabinoid interactions within key substrates involved in motivation and attention.