Biology subjects

Briand, L. A.

Publications and source records attributed to Briand, L. A..

5 recordsLinked to original sources

bioRxiv2024

Post-weaning social isolation alters sociability in a sex-specific manner

Adolescence is a critical period for brain development in humans and stress exposure during this time can have lasting effects on behavior and brain development. Social isolation and loneliness are particularly salient stressors that lead to detrimental mental health outcomes particularly in females, although most of the preclinical work on social isolation has been done in male animals. Our lab has developed a model of post-weaning adolescent social isolation that leads to increased drug reward sensitivity and altered neuronal structure in limbic brain regions. The current study utilized this model to determine the impact of adolescent social isolation on a three-chamber social interaction task both during adolescence and adulthood. We found that while post-weaning isolation does not alter social interaction during adolescence (PND45), it has sex-specific effects on social interaction in adulthood (PND60), potentiating social interaction in male mice and decreasing it in female mice. As early life stress can activate microglia leading to alterations in neuronal pruning, we next examined the impact of inhibiting microglial activation with daily minocycline administration during the first three weeks of social isolation on these changes in social interaction. During adolescence, minocycline dampened social interaction in male mice, while having no effect in females. In contrast, during adulthood, minocycline did not alter the impact of adolescent social isolation in males, with socially isolated males exhibiting higher levels of social interaction compared to their group housed counterparts. In females, adolescent minocycline treatment reversed the effect of social isolation leading to increased social interaction in the social isolation group, mimicking what is seen in naive males. Taken together, adolescent social isolation leads to sex-specific effects on social interaction in adulthood and adolescent minocycline treatment alters the effects of social isolation in females, but not males.

neuroscience↗

bioRxiv2024

Elevating levels of the endocannabinoid 2-arachidonoylglycerol blunts opioid reward but not analgesia

Converging findings have established that the endocannabinoid (eCB) system serves as a possible target for the development of new treatments for pain as a complement to opioid-based treatments. Here we show in male and female mice that enhancing levels of the eCB, 2-arachidonoylglycerol (2-AG), through pharmacological inhibition of its catabolic enzyme, monoacylglycerol lipase (MAGL), either systemically or in the ventral tegmental area (VTA) with JZL184, leads to a substantial attenuation of the rewarding effects of opioids in male and female mice using conditioned place preference and self-administration paradigms, without altering their analgesic properties. These effects are driven by CB1 receptors (CB1Rs) within the VTA as VTA CB1R conditional knockout, counteracts JZL184s effects. Conversely, pharmacologically enhancing the levels of the other eCB, anandamide (AEA), by inhibition of fatty acid amide hydrolase (FAAH) has no effect on opioid reward or analgesia. Using fiber photometry with fluorescent sensors for calcium and dopamine (DA), we find that enhancing 2-AG levels diminishes opioid reward-related nucleus accumbens (NAc) activity and DA neurotransmission. Together these findings reveal that 2-AG counteracts the rewarding properties of opioids and provides a potential adjunctive therapeutic strategy for opioid-related analgesic treatments.

neuroscience↗

bioRxiv2023

Connecting self-report and instrumental behavior during incubation of food craving in humans.

Incubation of craving is a phenomenon describing the intensification of craving for a reward over extended periods of abstinence from reinforcement. Animal models employ instrumental markers of craving to reward cues to examine incubation, while homologous human paradigms often rely on subjective self-reports. Here, we characterize a novel human paradigm that showed strong positive relationships between self-reports and instrumental markers of craving. Further, both measures expressed non-linear relationships with time since last consumption, which parallels homologous animal paradigms of incubation of craving.

neuroscience↗

bioRxiv2018

PKMζ in the nucleus accumbens acts to dampen cocaine seeking

The constitutively active, atypical protein kinase C, protein kinase M-{zeta} (PKM{zeta}), is exclusively expressed in the brain and its expression increases following exposure to drugs of abuse. However, the limitations of currently available tools have made it difficult to examine the role of PKM{zeta} in cocaine addiction. The current study demonstrates that constitutive deletion of PKM{zeta} potentiates cue-induced reinstatement of cocaine seeking and increases both food and cocaine taking, without affecting cue-driven food seeking in both male and female mice. Conditional deletion of PKM{zeta} within the nucleus accumbens recapitulated the increase in cocaine taking and seeking seen in the constitutive knockout mice, but only in male animals. Site-specific knockdown of PKM{zeta} in the nucleus accumbens had no effect on cocaine or natural reward behaviors in female mice. Taken together these results indicate that PKM{zeta} may act to dampen addictive phenotypes. Furthermore, these results indicate that PKM{zeta} is playing divergent roles in reward seeking in males and females.

neuroscience↗

bioRxiv2018

Adolescent Social Isolation Increases Vulnerability to Cocaine.

Childhood and adolescent adversity is associated with a wide range of psychiatric disorders, including an increased risk for substance abuse. Despite this, the molecular mechanisms underlying how chronic stress during adolescence alters reward signaling remains largely unexplored. Understanding how adolescent stress increases addiction-like phenotypes could inform the development of targeted interventions both before and after drug use. The current study examined how adolescent-onset isolation stress affected behavioral, molecular, and physiological responses to cocaine in male and female mice. Adolescent-onset social isolation did not alter the ability of mice to learn an operant response for food, nor influence food self-administration or motivation for food on a progressive ratio schedule. However, male and female socially stressed mice exhibited an increase in motivation for cocaine and cocaine seeking during a cue-induced reinstatement session. Additionally, we demonstrated that adolescent-onset social isolation increased cocaine-induced neuronal activation, as assessed by Fos expression, within the nucleus accumbens core and shell, ventral pallidum, dorsal bed nucleus of the stria terminalis, lateral septum and basolateral amygdala. Taken together, the present studies demonstrate that social stress during adolescence augments the behavioral responses to cocaine during adulthood and alters the responsiveness of reward-related brain circuitry.

neuroscience↗