Exploring the impact of adolescent exposure to cannabinoids and nicotine on psychiatric risk: insights from translational animal models

Adolescent co-exposure to environmental cadmium and high-fat diet induces cognitive decline via Larp7 m6A-mediated SIRT6 inhibition

The effects and underlying mechanisms of adolescent exposure to combined environmental hazards on cognitive function remain unclear. Here, using a combined exposure model, we found significant cognitive decline, hippocampal neuronal damage, and neuronal senescence in mice exposed to cadmium (Cd) and high-fat diet (HFD) during adolescence. Furthermore, we observed a significant downregulation of Sirtuin 6 (SIRT6) expression in the hippocampi of co-exposed mice. UBCS039, a specific SIRT6 activator, markedly reversed the above adverse effects. Further investigation revealed that co-exposure obviously reduced the levels of La ribonucleoprotein 7 (LARP7), disrupted the interaction between LARP7 and SIRT6, ultimately decreasing SIRT6 expression in mouse hippocampal neuronal cells. Overexpression of Larp7 reversed the combined exposure-induced SIRT6 decrease and senescence in mouse hippocampal neuronal cells. Additionally, the results showed notably elevated levels of Larp7 m6A and YTH domain family protein 2 (YTHDF2) in mouse hippocampal neuronal cells treated with the combined hazards. Ythdf2 short interfering RNA, RNA immunoprecipitation, and RNA stability assays further demonstrated that YTHDF2 mediated the degradation of Larp7 mRNA under combined exposure. Collectively, adolescent co-exposure to Cd and HFD causes hippocampal senescence and cognitive decline in mice by inhibiting LARP7-mediated SIRT6 expression in an m6A-dependent manner.

Brain dysfunctions and neurotoxicity induced by psychostimulants in experimental models and humans: an overview of recent findings

Preclinical and clinical studies indicate that psychostimulants, in addition to having abuse potential, may elicit brain dysfunctions and/or neurotoxic effects. Central toxicity induced by psychostimulants may pose serious health risks since the recreational use of these substances is on the rise among young people and adults. The present review provides an overview of recent research, conducted between 2018 and 2023, focusing on brain dysfunctions and neurotoxic effects elicited in experimental models and humans by amphetamine, cocaine, methamphetamine, 3,4-methylenedioxymethamphetamine, methylphenidate, caffeine, and nicotine. Detailed elucidation of factors and mechanisms that underlie psychostimulant-induced brain dysfunction and neurotoxicity is crucial for understanding the acute and enduring noxious brain effects that may occur in individuals who use psychostimulants for recreational and/or therapeutic purposes.

Identification of a novel fatty acid binding protein-5-CB2 receptor-dependent mechanism regulating anxiety behaviors in the prefrontal cortex

The endocannabinoid (eCB) system represents a promising neurobiological target for novel anxiolytic pharmacotherapies. Previous clinical and preclinical evidence has revealed that genetic and/or pharmacological manipulations altering eCB signaling modulate fear and anxiety behaviors. Water-insoluble eCB lipid anandamide requires chaperone proteins for its intracellular transport to degradation, a process that requires fatty acid-binding proteins (FABPs). Here, we investigated the effects of a novel FABP-5 inhibitor, SBFI-103, on fear and anxiety-related behaviors using rats. Acute intra-prelimbic cortex administration of SBFI-103 induced a dose-dependent anxiolytic response and reduced contextual fear expression. Surprisingly, both effects were reversed when a cannabinoid-2 receptor (CB2R) antagonist, AM630, was co-infused with SBFI-103. Co-infusion of the cannabinoid-1 receptor antagonist Rimonabant with SBFI-103 reversed the contextual fear response yet showed no reversal effect on anxiety. Furthermore, in vivo neuronal recordings revealed that intra-prelimbic region SBFI-103 infusion altered the activity of putative pyramidal neurons in the basolateral amygdala and ventral hippocampus, as well as oscillatory patterns within these regions in a CB2R-dependent fashion. Our findings identify a promising role for FABP5 inhibition as a potential target for anxiolytic pharmacotherapy. Furthermore, we identify a novel, CB2R-dependent FABP-5 signaling pathway in the PFC capable of strongly modulating anxiety-related behaviors and anxiety-related neuronal transmission patterns.

Enhancing the resolution of behavioral measures: Key observations during a forty year career in behavioral neuroscience

This manuscript reviews several key observations from the research program of Professor John P. Bruno that are believed to have significantly advanced our understanding of the brain's mediation of behavior. This review focuses on findings within several important research areas in behavioral neuroscience, including a) age-dependent neurobehavioral plasticity following brain damage; b) the role of the cortical cholinergic system in attentional processing and cognitive flexibility; and c) the design and validation of animal models of cognitive deficits in schizophrenia. In selecting these observations, emphasis was given to examples in which the heuristic potency was increased by maximizing the resolution and microanalysis of behavioral assays in the same fashion as one typically refines neuronal manipulations. Professor Bruno served the International Behavioral Neuroscience Society (IBNS) as an IBNS Fellow (1995-present) and President of the IBNS (2001-02).

A Randomized, Triple-Blind, Comparator-Controlled Parallel Study Investigating the Pharmacokinetics of Cannabidiol and Tetrahydrocannabinol in a Novel Delivery System, Solutech, in Association with Cannabis Use History

Background: An oral route of administration for tetrahydrocannabinol (Δ⁹-THC) and cannabidiol (CBD) eliminates the harmful effects of smoking and has potential for efficacious cannabis delivery for therapeutic and recreational applications. We investigated the pharmacokinetics of CBD, Δ⁹-THC, 11-OH-THC, and 11-nor-9-carboxy-Δ⁹-THC (THC-COOH) in a novel oral delivery system, Solutech™, compared to medium-chain triglyceride-diluted cannabis oil (MCT-oil) in a healthy population. Materials and Methods: Thirty-two participants were randomized and divided into two study arms employing a comparator-controlled, parallel-study design. To evaluate the pharmacokinetics of Δ⁹-THC, CBD, 11-OH-THC, and THC-COOH, blood was collected at pre-dose (t=0) and 10, 20, 30, and 45, min and 1, 1.5, 2, 2.5, 3, 4, 5, 6, 8, 12, 24, and 48 h post-dose after a single dose of Solutech (10.0 mg Δ⁹-THC, 9.76 mg CBD) or MCT (10.0 mg Δ⁹-THC, 9.92 mg CBD). Heart rate and blood pressure were measured at 0.5, 1, 2, 4, 6, 8, 12, 24, and 48 h. Relationships between cannabis use history, body mass index, sex, and pharmacokinetic parameters were investigated. Safety was assessed before and at 48 h post-acute dose. Results: Acute consumption of Solutech provided a significantly greater maximum concentration (C_max), larger elimination and absorption rate constants, faster time to C_max and lag time, and half-life for all analytes compared to MCT-oil (p<0.001). In addition, cannabis use history had a significant influence on the pharmacokinetic parameters of CBD, Δ⁹-THC, 11-OH-THC, and THC-COOH. On average, participants with later age of first use had higher Δ⁹-THC, CBD, and THC-COOH C_max and later time-to-C_max and half-life for Δ⁹-THC, CBD, THC-COOH, and 11-OH-THC than those with earlier age of first use (p≤0.032). Those with more years of recreational cannabis use had higher area under the curve for Δ⁹-THC and CBD, C_max for CBD, and longer 11-OH-THC half-life than those with less (p≤0.048). Conclusion: This study demonstrated that consumption of Solutech enhanced most pharmacokinetics parameters measured compared to MCT-oil. Participant's cannabis use history, including their age of first use and number of years using cannabis significantly impacted pharmacokinetic parameters investigated. Acute consumption of both products was found to be safe and well tolerated. The results suggest that Solutech may optimize bioavailability from cannabis formulations.

Exposure to Secondhand Smoke at Home and Psychological Distress among College Students in China: The Role of Parental Attachment

This study examined the link between home SHS exposure and psychological distress among college students in China. Between July and September of 2020, 18-25-year-old students in three Chinese universities were invited to complete an online survey. Data from 872 respondents (mean age = 20.28) were analyzed. Psychological distress was assessed by the 10-item Kessler Scale. Home SHS exposure was assessed by the presence of smoking household members, hours of exposure, and exposure to the number of cigarettes smoked. Maternal and paternal attachment were assessed by the Inventory of Parent and Peer Attachment. Pairwise comparisons of sample characteristics were performed across never-smokers, triers (smoked one or two puffs), and smokers. Generalized linear regression models were constructed to assess the association. More smokers were exposed to home SHS or engaged in ever alcohol and other drug use than never-smokers. In never-smokers, exposure for <1 h/day or ≥3 h/day, or to 6-10 cigarettes/day was associated with increased psychological distress, but they were nullified after adjusting for parental attachment. In smokers, exposure to 6-10 cigarettes/day was associated with decreased psychological distress even after adjusting for parental attachment. Home SHS exposure is a risk factor for psychological wellbeing in never-smokers, the association with smokers warrants further study.

Innovative screening models for the discovery of new schizophrenia drug therapies: an integrated approach

Introduction: Schizophrenia is a severe psychiatric disorder affecting millions worldwide. However, available treatment options do not fully address the disease. Whereas current antipsychotics may control psychotic symptoms, they seem notoriously ineffective in improving negative and cognitive symptoms or in preventing functional decline. As the etiology of schizophrenia eludes us, the development of valid animal models for screening new drug targets appears to be a strenuous task.Areas covered: In this review, the authors present the key concepts that validate animal models of schizophrenia, as well as the different screening approaches for novel schizophrenia treatments. The models covered are either based on major neurotransmitter systems or neurodevelopmental, immune, and genetic approaches.Expert opinion: Sadly, due to inertia, research focuses on developing 'anti-psychotics', instead of 'anti-schizophrenia' drugs that would tackle the entire syndrome of schizophrenia. Whereas no perfect model may ever exist, combining different experimental designs may enhance validity, as the over-reliance on a single model is inappropriate. Multi-model approaches incorporating vulnerability, the 'two-hit' hypothesis, and endophenotypes offer a promise for developing new strategies for schizophrenia treatment. Forward and reverse translation between preclinical and clinical research will increase the probability of success and limit failures in drug development.