More Like this

1. Utilizing the commodity purchase task to evaluate behavioral economic demand for illicit substances: a review and meta‐analysis

   https://doi.org/10.1111/add.14792  

   Strickland, Justin C. ; Campbell, Ethan M. ; Lile, Joshua A. ; Stoops, William W. ( October 2019 , Addiction)

   The commodity purchase task is a simulated demand procedure that is easy and quick to complete (< 5 minutes) as well as adaptable for remote delivery and use with varied study populations. The purpose of this meta‐analysis was to synthesize research using the commodity purchase task with illicit substances to evaluate the magnitude of omnibus effects sizes and moderators of the correlation of demand indices with quantity–frequency (QF) and severity measures.

   Random‐effects meta‐analyses and meta‐regressions involving studies with cross‐sectional correlational designs.

   Eleven studies, 10 outcomes and 2146 participants from two countries (USA and UK) published up to 1 October 2018.

   Omnibus effect sizes (correlation coefficients) of five demand indices from the commodity purchase task [intensity (unconstrained consumption), elasticity (price sensitivity), O_max(maximum expenditure), P_max(price at maximum expenditure) and breakpoint (first price of zero consumption)] with QF and severity measures. Meta‐regression models tested moderators of effect sizes (i.e. sample age and sex composition, commodity type and number of prices used in the commodity purchase task).

   Significant omnibus effect sizes were observed with QF and severity measures for intensity (r = 0.32/0.28, QF/severity, respectively), elasticity (r = −0.14/−0.18), O_max(r = 0.30/0.29) and breakpoint (r = 0.17/0.22) values. P_maxwas only significantly associated with severity measures (r = 0.15). The percentage of female participants and number of prices used in the purchase task significantly moderated P_maxand breakpoint effect‐size estimates in that stronger associations were observed in samples with a greater percentage of women and in studies using tasks with more price points. Commodity type (cannabis versus cocaine) did not significantly moderate associations involving any demand index.

   Behavioral economic demand as measured by the commodity purchase task is consistently correlated with measures of illicit substance use quantity–frequency and severity.

    

   more » « less
2. Oestradiol influences on dopamine release from the nucleus accumbens shell: sex differences and the role of selective oestradiol receptor subtypes

   https://doi.org/10.1111/bph.14531  

   Yoest, Katie E. ; Cummings, Jennifer A. ; Becker, Jill B. ( December 2018 , British Journal of Pharmacology)

   Females are more sensitive than males to both the acute and prolonged effects of psychomotor stimulants. In females, this is regulated by oestradiol, which enhances dopamine release in the dorsal striatum. In this study, we tested the acute effect of oestradiol on dopamine release in the nucleus accumbens (NAc) shell after cocaine administration and investigated which oestradiol receptors (ERs) contribute to sex differences in the response to cocaine.

   The ability of oestradiol benzoate (EB) to acutely modulate the effect of cocaine on phasic dopamine release in the NAc shell was measured by fast‐scan cyclic voltammetry in anaesthetized male and female rats. The roles of ER subtypes, ERα and ERβ, was determined with selective agonists.

   EB acutely enhanced the effect of cocaine on stimulated dopamine release from the NAc shell in females but not in male rats only at levels of stimulation expected to optimally saturate dopamine transporters. Enhanced dopamine release after cocaine administration was also observed in females after selective activation of ERβ but not ERα. EB attenuated the effect of cocaine on NAc shell dopamine reuptake in males but not in females.

   Oestradiol acutely and rapidly regulates dopamine release in females and dopamine reuptake in males. In females, oestradiol rapidly enhances the effect of cocaine on dopamine release, likelyviaactivation of ERβ. The effect of oestradiol in males is not seen with selective receptor subtype activation, a topic deserving of further study.

   This article is part of a themed section on The Importance of Sex Differences in Pharmacology Research. To view the other articles in this section visithttp://onlinelibrary.wiley.com/doi/10.1111/bph.v176.21/issuetoc

    

   more » « less
3. Estrous Cycle Mediates Midbrain Neuron Excitability Altering Social Behavior upon Stress

   https://doi.org/10.1523/JNEUROSCI.1504-22.2022  

   Shanley, Mary R. ; Miura, Yuka ; Guevara, Christopher A. ; Onoichenco, Amanda ; Kore, Rufina ; Ustundag, Emine ; Darwish, Rania ; Renzoni, Lauren ; Urbaez, Ashley ; Blicker, Ella ; et al ( December 2022 , The Journal of Neuroscience)

   The estrous cycle is a potent modulator of neuron physiology. In rodents,in vivoventral tegmental area (VTA) dopamine (DA) activity has been shown to fluctuate across the estrous cycle. Although the behavioral effect of fluctuating sex steroids on the reward circuit is well studied in response to drugs of abuse, few studies have focused on the molecular adaptations in the context of stress and motivated social behaviors. We hypothesized that estradiol fluctuations across the estrous cycle acts on the dopaminergic activity of the VTA to alter excitability and stress response. We used whole-cell slice electrophysiology of VTA DA neurons in naturally cycling, adult female C57BL/6J mice to characterize the effects of the estrous cycle and the role of 17β-estradiol on neuronal activity. We show that the estrous phase alters the effect of 17β-estradiol on excitability in the VTA. Behaviorally, the estrous phase during a series of acute variable social stressors modulates subsequent reward-related behaviors. Pharmacological inhibition of estrogen receptors in the VTA before stress during diestrus mimics the stress susceptibility found during estrus, whereas increased potassium channel activity in the VTA before stress reverses stress susceptibility found during estrus as assessed by social interaction behavior. This study identifies one possible potassium channel mechanism underlying the increased DA activity during estrus and reveals estrogen-dependent changes in neuronal function. Our findings demonstrate that the estrous cycle and estrogen signaling changes the physiology of DA neurons resulting in behavioral differences when the reward circuit is challenged with stress.

   SIGNIFICANCE STATEMENTThe activity of the ventral tegmental area encodes signals of stress and reward. Dopaminergic activity has been found to be regulated by both local synaptic inputs as well as inputs from other brain regions. Here, we provide evidence that cycling sex steroids also play a role in modulating stress sensitivity of dopaminergic reward behavior. Specifically, we reveal a correlation of ionic activity with estrous phase, which influences the behavioral response to stress. These findings shed new light on how estrous cycle may influence dopaminergic activity primarily during times of stress perturbation.

    

   more » « less
4. Transient Copper Exposure During Embryogenesis and Temperature Affect Developmental Rate, Survival, and Fin Regeneration in Japanese Medaka ( Oryzias latipes )

   https://doi.org/10.1002/etc.5276  

   Mason, Marilyn W. ; Bertucci, Emily M. ; Leri, Faith M. ; Parrott, Benjamin B. ( January 2022 , Environmental Toxicology and Chemistry)

   Combined environmental stressors that an organism experiences can have both immediate and lasting consequences. In the present study, we exposed Japanese medaka (Oryzias latipes) embryos to sublethal copper sulfate (CuSO₄; 0, 10, and 100 ppb) in combination with different rearing temperatures (27, 30, and 33 °C) to assess acute and latent effects on development, growth, and regenerative capacity. Embryos exposed to CuSO₄and/or higher temperatures hatched significantly earlier. At 4 months post‐exposure, fish exposed to low levels of CuSO₄during development had higher survival, whereas fish exposed to both 100 ppb CuSO₄and 33 °C temperatures had significantly lower survival. In addition, a sex‐specific effect of embryonic CuSO₄exposure was observed as female mass decreased with increasing Cu dose. We also assessed caudal fin regenerative capabilities in both embryo‐exposed fish at 4 months of age and adult medaka that were exposed to 0, 10, and 100 ppb CuSO₄at room temperature during a 14‐day trial. Whereas fin regeneration was unaffected by adult exposure to Cu, fish transiently exposed during embryogenesis displayed an initial increase in fin growth rate and an increased incidence of abnormal fin morphology following regrowth. Collectively, these data suggest that developmental Cu exposure has the potential to exert long‐lasting impacts to organismal growth, survival, and function.Environ Toxicol Chem2022;41:748–757. © 2021 SETAC

    

   more » « less
5. Reproductive challenges related to a complex sexual system in Euphorbia rosescens , a rare endemic herb

   https://doi.org/10.1111/1442-1984.12409  

   Faivre, Amy E. ; Smith, Stacy A. ( April 2023 , Plant Species Biology)

   When the sexual system of a rare plant species is complex, characterizing floral development, plant morphology, and subpopulation structure is essential for assessing reproductive potential. Availability of pollinator rewards and positioning of sexual morphs within inflorescences relates to outcrossing potential. We studied the complex sexual system of the recently discoveredEuphorbia rosescensE.L. Bridges & Orzell, a rare species occurring in a single Florida county.Euphorbia rosescenshas both monomorphic subpopulations of female plants and mixed subpopulations with male and andromonoecious plants. Most data on cyathia sex, inflorescence architecture, floral visitors, and fruit set came from one female subpopulation and one mixed subpopulation. Cyathia longevity, flowering phase, nectar secretion, pollen production, and viability were measured in female, male, and hermaphrodite cyathia. Female plants had fewer inflorescence levels and cyathia and significantly smaller cyathia than male and andromonoecious plants. Andromonoecious plants were larger and produced more cyathia relative to male plants. Within mixed populations, sex switching occurred in both directions between male and andromonoecious plants. Female plants did not switch sexes. Proximal to distal inflorescence levels transitioned from hermaphrodite to male cyathia on andromonoecious plants. Nectar secretion corresponded to initiation of staminate flowering, but in female cyathia stigmas were receptive approximately a day before nectar secretion. Pollen production and viability were similar in male and hermaphrodite cyathia. Fruit maturation was minimal, primarily observed on andromonoecious plants. Nectar availability, pollen rewards, trimorphic inequalities in inflorescence display, and low fruit set suggest high geitonogamy, thus limiting outcrossing potential for this species.

    

   more » « less