No abstract

Exercise increases serum opioid levels and improves cardiovascular health. Here we tested the hypothesis that opioids contribute to the acute cardioprotective effects of exercise using a rat model of exercise-induced cardioprotection. For the standard protocol, rats were randomized to 4 days of treadmill training and 1 day of vigorous exercise (day 5), or to a sham exercise control group. On day 6, animals were killed, and global myocardial ischemic tolerance was assessed on a modified Langendorff apparatus. Twenty minutes of ischemia followed by 3 h of reperfusion resulted in a mean infarct size of 42 +/- 4% in hearts from sham exercise controls and 21 +/- 3% (P < 0.001) in the exercised group. The cardioprotective effects of exercise were gone by 5 days after the final exercise period. To determine the role of opioid receptors in exercise-induced cardioprotection, rats were exercised according to the standard protocol; however, just before exercise on days 4 and 5, rats were injected subcutaneously with 10 mg/kg of the opioid receptor antagonist naltrexone. Similar injections were performed in the sham exercise control group. Naltrexone had no significant effect on baseline myocardial ischemic tolerance in controls (infarct size 43 +/- 4%). In contrast, naltrexone treatment completely blocked the cardioprotective effect of exercise (infarct size 40 +/- 5%). Exercise was also associated with an early increase in myocardial mRNA levels for several opioid system genes and with sustained changes in a number of genes that regulate inflammation and apoptosis. These findings demonstrate that the acute cardioprotective effects of exercise are mediated, at least in part, through opioid receptor-dependent mechanisms that may include changes in gene expression.

No abstract

In the primary care setting, rotator cuff pathology is commonly encountered. Information regarding the risks of oral medications for the management of the associated pain keeps mounting. Partial-thickness rotator cuff tears remain difficult to diagnose with a single imaging modality. Musculoskeletal education in medical schools and non-orthopaedic residency and fellowship training programs continues to be an area for additional improvement. In the primary care office, the initial evaluation of shoulder pain should include a thorough musculoskeletal evaluation in order to identify the source of the pain (e.g., shoulder, cervical spine, chest wall), as well as the development of an initial treatment plan. Access to imaging modalities such as ultrasound and MRI can vary depending on the resources available in the primary care setting. The identification of patients who may benefit from early surgical referral is imperative for optimizing outcomes.