Methadone Access for Opioid Use Disorder During the COVID-19 Pandemic Within the United States and Canada.

Importance: Methadone access may be uniquely vulnerable to disruption during COVID-19, and even short delays in access are associated with decreased medication initiation and increased illicit opioid use and overdose death. Relative to Canada, US methadone provision is more restricted and limited to specialized opioid treatment programs.

Objective: To compare timely access to methadone initiation in the US and Canada during COVID-19.

Selective activation of estrogen receptors α and β: Implications for depressive-like phenotypes in female mice exposed to chronic unpredictable stress.

The estrogen receptor (ER) mechanisms by which 17β-estradiol influences depressive-like behaviour have primarily been investigated acutely and not within an animal model of depression. Therefore, the current study aimed to dissect the contribution of ERα and ERβ to the effects of 17β-estradiol under non-stress and chronic stress conditions. Ovariectomized (OVX) or sham-operated mice were treated chronically (47 days) with 17β-estradiol (E2), the ERβ agonist diarylpropionitrile (DPN), the ERα agonist propylpyrazole-triol (PPT), or vehicle.

Androgens Enhance Adult Hippocampal Neurogenesis in Males but Not Females in an Age-Dependent Manner.

Androgens (testosterone and DHT) increase adult hippocampal neurogenesis by increasing survival of new neurons in male rats and mice via an androgen receptor pathway, but it is not known whether androgens regulate neurogenesis in female rats and whether the effect is age-dependent. We investigated the effects of DHT, a potent androgen, on neurogenesis in young adult and middle-aged male and female rats. Rats were gonadectomized and injected with the DNA synthesis marker bromodeoxyuridine (BrdU).

Chronic aromatase inhibition increases ventral hippocampal neurogenesis in middle-aged female mice.

Letrozole, a third-generation aromatase inhibitor, prevents the production of estrogens in the final step in conversion from androgens. Due to its efficacy at suppressing estrogens, letrozole has recently taken favor as a first-line adjuvant treatment for hormone-responsive breast cancer in middle-aged women. Though patient response to letrozole has generally been positive, there is conflicting evidence surrounding its effects on the development of depression.

Early and late effects of maternal experience on hippocampal neurogenesis, microglia, and the circulating cytokine milieu.

The maternal brain displays considerable plasticity, and motherhood is associated with changes in affective and cognitive function. Motherhood can alter the trajectory of brain aging, including modifications to neuroplasticity and cognition. Here, we investigated the short- and long-term effects of motherhood on hippocampal neurogenesis, microglial density and morphology, and circulating cytokines, domains known to be altered with age and implicated in cognition and mood.

Ovarian hormones, but not fluoxetine, impart resilience within a chronic unpredictable stress model in middle-aged female rats.

Depression is more prevalent in women than in men, and women are at a heightened risk for depression during the postpartum and perimenopause. There is also evidence to suggest that the ovarian hormone milieu may dictate antidepressant efficacy. Thus, it is important to investigate the role of ovarian hormones in the pathogenesis of depression and in the mechanisms that may underlie antidepressant efficacy.