Clonidine normalizes low plasma beta-endorphin concentration and blood pressure in young men with mild essential hypertension

A study of maternal plasma beta-endorphin in pre-eclamptic women during labour

This prospective study was undertaken to determine the maternal plasma beta-endorphin levels in pre-eclamptic women during labour and to explore any correlation between the levels and the severity of pre-eclampsia. A total of 50 primiparous women at term were recruited over a period of 5 years. Twenty-five with pre-eclampsia and 25 healthy women considered as a control group. The mean concentration of maternal plasma beta-endorphin in pre-eclamptic group (22.73+/-8.02 pmol/l) was significantly lower (p<0.001) than that of the control group (48.38+/-5.94 pmol/l). A highly significant (p<0.001) negative correlation was found between maternal plasma beta-endorphin levels and both systolic and diastolic blood pressures in pre-eclamptic group.

Stress and endogenous opioids: behavioral and circulatory interactions

Endogenous opioid peptides are the basis of a diverse system of complex neuroregulatory and endocrine mechanisms. While relatively quiescent in the resting state, these peptides are released during intense stimulation and modify, in a number of ways, circulatory homeostatic mechanisms. The endogenous opioids, primarily via endorphins and enkephalins, are capable of influencing circulatory responses to stress at the behavioral, the endocrinological, and the neural level. Recent research in humans and animals has described several roles for opioids in regulation of the circulatory stress response, and has also provided clues about the significance of opioid dysregulation in the pathophysiology of stress. Increased understanding of the basic mechanisms of stress and endogenous opioids will clarify the potential roles of opioids in important pharmacologic and behaviorally based therapeutics.

Effect of clonidine on beta-endorphin, ACTH and cortisol secretion in essential hypertension and obesity

The role of alpha 2-adrenoceptor stimulation by clonidine on the secretion of beta-endorphin, ACTH, and cortisol in essential hypertension and obesity was studied in 45 subjects: 15 non-obese hypertensives, 10 obese hypertensives, 11 obese normotensives, and 9 healthy subjects. The circadian rhythm of plasma beta-endorphin, ACTH, and cortisol was determined after placebo and after three days on clonidine 0.45 mg daily. Clonidine lowered the blood pressure and blood ACTH and cortisol levels in all the subjects. A significant decrease in beta-endorphin after clonidine occurred in the healthy subjects. In obese normotensives basal beta-endorphin concentrations were significantly higher than in healthy subjects and did not change after clonidine. In about 50% of non-obese and obese hypertensives a significant increase in beta-endorphin secretion after clonidine was noted (responders). In the subgroup of non-obese hypertensive responders no circadian rhythm of beta-endorphin was observed. The results suggest that adrenergic regulation of beta-endorphin secretion is altered in obesity and in certain patients with essential hypertension.

Endogenous opiates: 1986

This is the ninth installment of our annual review of research involving the endogenous opiate peptides. It is restricted to the non-analgesic and behavioral studies of the opiate peptides published in 1986. The specific topics this year include stress; tolerance and dependence; eating; drinking; gastrointestinal, renal, and hepatic processes; mental illness; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; activity; sex, pregnancy, and development; and some other behaviors.