How Endorphins Control Body Functions
Endorphins effects
Positive reward Endorphins may substitute for intracranial self-stimulation reward in animals experiments, proving their important role in the brain system of pleasure (53, 59). Mood enhancement, shown to correlate with endorphin level, correlated also with analgesia and suppression of food intake (110). Normal concentration of endorphins in the blood correlated with mood enhancement and euphoria, their deficit correlated with aggressiveness. endorphins replacement treated phobias (74, 8, 110).
Placebo Endorphins has been shown to participate in placebo effects: treating subjects with endorphins antagonist naloxon eliminated placebo response in double blind control study (37).
Stress Endorphins participate in both local and general adaptation syndromes due to stress: they provide inhibition of plasma concentration of epinephrine and cortisol and stimulate the pineal gland, causing the release of anti stress hormone melatonin (32, 39, 66, 75, 88, 93, 12, 105).
Appetite/Hunger Numerous experimental and clinic data show that defects in the endorphin system of the body may lead to both obesity (43, 212 77, 113, 125) and anorexia (6, 60, 81). Neurophysiological mechanisms of food intake regulation suggest (among others) the participation of a prominent appetite suppressant Cholecystokinin (7, 57) and endorphin in activities of the specific for appetite control brain areas -- ventromedial nuclei and lateral hypothalamic areas (111, 60, 55, 77, 79). Chronic endorphins administration decreases body weight, while inhibition of endorphin activity facilitates weight gain in nervous anorexia (23, 65). However, it does not seem that endorphins control long-term processes of maintaining body weight. Rather than hunger, they modulate short-term control of appetite and mechanisms of positive reward, "pleasure" (46, 65, 79, 103, 113).
Body temperature Endorphins lead to increased peripheral vasoconstriction, inhibition of heat loss, increase of oxidative metabolism, and modification of behavioral thermoregulation resulting in an elevation of body temperature (17, 18, 25, 44, 47, 49, 114, 117, 121).
Blood glucose Besides their stimulatory effect on insulin secretion, endorphins provide modulation of pancreatic function to control both hyper- and hypoglycemia e.g., through stimulation of glucagon release (21, 28, 32, 43, 62, 68)
Immune system There is a growing body of evidence about strong immunostimulatory action of endorphins (78, 90, 51, 52, 57, 63, 72, 94, 95, 100, 101, 106, 112, 115, 116, 130).
Growth hormone Endorphins are potent stimulators of growth hormone secretion (12, 14, 68, 88, 90, 119, 128).
Other hormones Besides the growth hormone release, endorphins control a number of other hormonal mechanisms such as those regulating reproductive functions (parturation, lactation, etc.), stress management and environmental adaptation (96, 109, 18, 33, 37, 98, 122).
Oxygen utilization Sufficient concentration of endogenous opiates have shown to be essential for the oxygen utilization and other defensive mechanisms during hypoxia (3, 4, 40, 69, 50).
ParkinsonÃs disease Endorphin-sensitive neurons have direct contact with and control upon dopaminergic neurons, the fact that may relate to treatment of ParkinsonÃs disease (27, 41, 84).
PMS PMS has been demonstrated to correlate with endogenous opiates system dysfunction. Significantly lower levels of plasma beta-endorphin levels were found at the onset of the hot flashes than 5 to 20 minutes before (35, 36, 54, 58, 117).
Schizophrenia The instability of endorphin secretion may contribute to the pathogenesis of schizophrenia. On the other hand, endorphins possess anti psychotic efficacy in patients with schizophrenia (42, 107, 124).
Seizures The lack of endorphins correlated with higher probability of many seizure kinds, their injections inhibited epileptiform activities in the different regions of the brain (15, 5, 29, 76). The relaxation response of endorphins, as well as their anti epileptic action, includes their ability to release inhibitory neuromediator GABA (87)
