Related Experiment Video
Updated: May 31, 2026

Polygraphic Recording Procedure for Measuring Sleep in Mice
Published on: January 25, 2016
Cardiovascular Responses to Tonic Pain in REM Sleep-Deprived Rats: Role of Melatonin and Beta Endorphin
Salah Kassab1, Usha Sachdeva, Nagalla Das
1Department of Physiology, College of Medicine and Medical Sciences, Arabian Gulf University, P.O. Box 22979, Manama, Bahrain.
Objective:
Chronic pain is associated with increased incidence of hypertension. Sleep deprivation, common in patients with chronic pain, is associated with increased blood pressure and heart rate. This study was designed to determine whether sleep deprivation induces increased cardiovascular responses to pain. In addition; we examined the role of melatonin and endorphins in mediating these responses.
Method:
The study was conducted in Sprague-Dawely rats divided into a control group (n=8) and Rapid Eye Moment sleep deprived (REMSD) group (n=8). REM sleep deprivation was done for three days using the inverted flowerpot technique. Systolic BP and HR were recorded at baseline as well as 5, 10 and 30 minutes after intra-plantar formalin injection. In addition, serum melatonin and endorphin levels were determined.
Results:
Under basal conditions, BP and HR and following acute pain (1(st) phase of formalin injection) were comparable with non-sleep deprived (non-SD) state. In contrast, the REMSD rats showed significantly greater increases in HR and BP during the 2(nd) phase of formalin pain as compared to non-SD state. These changes were associated with significant reductions in serum melatonin and endorphin levels in REMSD rats.
Conclusion:
These data indicate that exaggerated blood pressure and HR responsiveness to pain in sleep deprivation could be mediated through reductions in melatonin and endorphin.
Related Concept Videos
Management of Insomnia
REM Sleep Behavior Disorder
RBD is significantly associated with...
Sedatives and Hypnotics Drugs: Miscellaneous Agents
Melatonin congeners like ramelteon (Rozerem) and tasimelteon (Hetlioz) selectively bind to melatonin receptors (MT1 and MT2) and thus mimic the actions of melatonin, a hormone that regulates sleep-wake cycles. Tasimelteon is primarily used for non-24-hour sleep-wake disorder, common in blind patients. They are also used to treat conditions like insomnia...
Sleep-Wake Cycles
NREM Sleep
NREM sleep comprises four progressive stages that seamlessly merge:
Understanding Sleep
The circadian rhythm, a nearly 24-hour cycle, is deeply influenced by environmental light cues. Light exposure directly affects the hypothalamus, which in turn regulates...
Analgesia and Pain Management

