Carotid baroreflex sensitivity at rest and during exercise is not influenced by opioid receptor antagonism

The Effects of Physical Exercise on Saliva Composition: A Comprehensive Review

Saliva consists of organic and inorganic constituents. During exercise, analysis of the saliva can provide valuable information regarding training stress, adaptation and exercise performance. The objective of the present article was to review the effect of physical exercise on saliva composition. The shift in the composition of the saliva, during and after a workout, reflects the benefits of exercise, its potential risks and the capability of the saliva to serve as a health indicator. The type and the frequency of training, the physical condition and the athletes’ general health influence the hormones, immunoglobulins and saliva enzymes. The correlation between saliva and physical exercise has to be further investigated and the available knowledge to be applied for the benefit of the athletes during sports activities.

Variations of perioperative baroreflex sensitivity in hypertensive and normotensive patients

BACKGROUND

Impaired baroreflex sensitivity (BRS) is a marker of autonomous dysfunction, which may play an important role in the long-term development of hypertension. Perioperative patients with hypertension are rapidly increasing in all populations worldwide.

OBJECTIVE

To estimate the value of BRS for hypertension in a surgery cohort.

METHODS

An observational and cross-sectional study was performed, involving 96 patients who underwent video-assisted thoracoscopic pulmonary lobectomy or segmentectomy. Invasive blood pressure and heart rate before and after giving nitroglycerin were measured in 48 normotensive patients and 48 hypertensive patients (25 and 23 undergoing regular treatment hypertensive [HR] and irregular treatment hypertensive [HI], respectively) while entering the operation room, 30 minutes after skin incision, and 10 minutes after skin suture.

RESULTS

BRS_preoperative of hypertensive group (Group H) was lower than normotensive group (Group N) (3.49 ± 1.55 vs. 5.75 ± 4.15 ms/mmHg; P < 0.05). BRS_{intraoperative} of Group H was lower than Group N (1.70 ± 1.18 vs. 2.84 ± 1.11 ms/mmHg; P < 0.05). BRS_preoperative of patients in irregular-treated group (Group HI) was lower than regular-treated group (Group HR) (2.92 ± 1.36 vs. 4.31 ± 1.87 ms/mmHg; P < 0.05). BRS_{intraoperative} of Group HI was lower than Group HR (1.45 ± 0.90 vs. 2.08 ± 1.82 ms/mmHg; P < 0.05). BRS_{intraoperative} and BRS_{postoperative} were lower than BRS_preoperative in each group (P < 0.01).

CONCLUSION

The perioperative autonomic nerve function was significantly impaired in hypertensive patients. This effect was less pronounced for those who were on regular antihypertensive treatment. Attention should be paid to maintain the stability of cardiovascular function, to ensure patients can go through perioperative period safely.

Hormonal responses to opioid receptor blockade: during rest and exercise in cold and hot environments

Opioid receptors appear to modulate a variety of physiological and metabolic homeostatic responses to stressors such as exercise and thermally extreme environments. To more accurately determine the role of the naloxone (NAL) sensitive opioid receptor system during rest and exercise, subjects were subjected to concomitant environmental thermal stress. Fifteen untrained men rested or performed low intensity (60% VO2peak) or high intensity (80% VO2peak) exercise on a cycle ergometer for 60 min in an environmental chamber during cold (0 degrees C) hot (35 degrees C) air exposure while receiving an infusion of normal saline (SAL) or NAL (0.1 mg kg(-1)). Plasma adrenocorticotropin hormone (ACTH), immunoreactive beta-endorphin (IBE), cortisol and growth hormone were measured at baseline and every 15 min while in the chamber. Time to exhaustion was significantly reduced during high intensity exercise in the heat (P<0.0001). NAL significantly (P=0.0004) reduced the time to exhaustion (38.3+/-2.1 min) during high intensity exercise in the heat compared to SAL (49.4+/-2.1 min). ACTH and IBE increased during hot conditions and cold attenuated this response. Plasma concentrations of IBE, ACTH, and growth hormone increased significantly with NAL during high intensity exercise in the heat compared to SAL. Cold attenuated the response of ACTH, IBE and cortisol to NAL. NAL administration exaggerates plasma hormone concentration during high intensity exercise in the heat, but not cold. These results support a regulatory effect of the opioid receptor system on physiological responses during exercise in thermally stressful environments. Future research should be directed to more clearly defining the effect of environmental temperature on the mechanism of hypothalamic-pituitary-adrenal hormonal release during exercise and hot environmental temperatures.