How physical activity behavior affected well-being, anxiety and sleep quality during COVID-19 restrictions in Iran.

OBJECTIVE: The Islamic Republic of Iran has displayed one of the highest rates of COVID-19 infection in the world and the highest rate of mortality in the Middle East. Iran has used a stringent package of preventive health measures to mitigate the spread of infection, which however has negatively affected individuals' physical and psychological health. This study aimed at examining whether physical-activity (PA) behavior, anxiety, well-being, and sleep-quality changed in response to the COVID-19-related public health restrictions enforced in Iran. PATIENTS AND METHODS: An online questionnaire was disseminated to adults residing in Iran from November 17, 2020, to February 13, 2021 (~88 days), during Iran's strictest public health restrictions. Main outcome measures included Godin-Shephard Leisure-Time Exercise Questionnaire, General Anxiety Disorder-7, Mental Health Continuum-Short Form, and Pittsburgh Sleep Quality Index. RESULTS: A total of 3,323 adults (mean age 30±11 years, 54.3% female) participated in the survey. Firstly, the restrictions generally reduced PA behavior: (a) among inactive participants (IPs), 60.6% became less active vs. 5.1% who became more active; and (b) among active participants (APs), 49.9% became less active vs. 22.8% who became more active. Secondly, PA behavior was associated with higher well-being and sleep quality during the restrictions: (a) APs reported higher (or lower) levels of well-being and sleep quality (or anxiety) than did IPs; and (b) among IPs as well as among APs, the more active the participants, the greater (or lower) the levels of well-being and sleep quality (or anxiety). CONCLUSIONS: This study showed the beneficial role of PA behavior for well-being, anxiety, and sleep quality during the COVID-19 restrictions, whereas such restrictions appeared to decrease PA participation. Active lifestyle should be then encouraged during the COVID-19 outbreak while taking precautions.

Anti-nociception mediated by a κ opioid receptor agonist is blocked by a δ receptor agonist.

BACKGROUND AND PURPOSE: The opioid receptor family comprises four structurally homologous but functionally distinct sub-groups, the µ (MOP), δ (DOP), κ (KOP) and nociceptin (NOP) receptors. As most opioid agonists are selective but not specific, a broad spectrum of behaviours due to activation of different opioid receptors is expected. In this study, we examine whether other opioid receptor systems influenced KOP-mediated antinociception. EXPERIMENTAL APPROACH: We used a tail withdrawal assay in C57Bl/6 mice to assay the antinociceptive effect of systemically administered opioid agonists with varying selectivity at KOP receptors. Pharmacological and genetic approaches were used to analyse the interactions of the other opioid receptors in modulating KOP-mediated antinociception. KEY RESULTS: Etorphine, a potent agonist at all four opioid receptors, was not anti-nociceptive in MOP knockout (KO) mice, although etorphine is an efficacious KOP receptor agonist and specific KOP receptor agonists remain analgesic in MOP KO mice. As KOP receptor agonists are aversive, we considered KOP-mediated antinociception might be a form of stress-induced analgesia that is blocked by the anxiolytic effects of DOP receptor agonists. In support of this hypothesis, pretreatment with the DOP antagonist, naltrindole (10 mg·kg(-1) ), unmasked etorphine (3 mg·kg(-1) ) antinociception in MOP KO mice. Further, in wild-type mice, KOP-mediated antinociception by systemic U50,488H (10 mg·kg(-1) ) was blocked by pretreatment with the DOP agonist SNC80 (5 mg·kg(-1) ) and diazepam (1 mg·kg(-1) ). CONCLUSIONS AND IMPLICATIONS: Systemic DOP receptor agonists blocked systemic KOP antinociception, and these results identify DOP receptor agonists as potential agents for reversing stress-driven addictive and depressive behaviours mediated through KOP receptor activation. LINKED ARTICLES: This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.