Background: Animals have an internal biological clock with melatonin hormone that helps them to adapt to light/dark circles. Since melatonin is associated with an alteration in the expression and production of opioid receptors, this study aimed to evaluate the effect of changes in the light/dark circles on pain sensation in rats. Methods: This research study in order to investigate the thermal...

conclusions our findings clearly indicate a synergistic effect of waterpipe smoke, immobilization and darkness stress on serum ck levels, whereas serum alp levels of experimental groups have shown no significant synergism for the mentioned factors. results the results indicated enhanced serum ck and alp levels in all groups compared with control (p < 0.05). also, there was a significant differe...

In the current research, we extend past work on the effects of ambient darkness and threat to the domain of memory for expressive faces. In one study, we examined the effects of ambient darkness and individual differences in state anxiety on memory of unfamiliar expressive faces. Here, participants were seated in either a dark or light room and encoded a set of unfamiliar faces with angry, happ...

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