Neuroendocrine evaluation of central opiate activity in primary headache disorders

Role of Estrogens in Menstrual Migraine

Migraine is a major neurological disorder affecting one in nine adults worldwide with a significant impact on health care and socioeconomic systems. Migraine is more prevalent in women than in men, with 17% of all women meeting the diagnostic criteria for migraine. In women, the frequency of migraine attacks shows variations over the menstrual cycle and pregnancy, and the use of combined hormonal contraception (CHC) or hormone replacement therapy (HRT) can unveil or modify migraine disease. In the general population, 18–25% of female migraineurs display a menstrual association of their headache. Here we present an overview on the evidence supporting the role of reproductive hormones, in particular estrogens, in the pathophysiology of migraine. We also analyze the efficacy and safety of prescribing exogenous estrogens as a potential treatment for menstrual-related migraine. Finally, we point to controversial issues and future research areas in the field of reproductive hormones and migraine.

Electrophysiological evidence for trigeminal neuron sensitization in patients with migraine

The electrically elicited corneal reflex is a useful tool for exploring the trigeminal system in humans and it may provide additional evidence pointing to a dysfunction of this system in migrainous patients. Tactile perception, corneal reflex and pain thresholds were studied in 48 migraine without aura patients during pain-free periods and compared with those observed in 24 controls. Twenty-eight of the patients had strictly unilateral headache, while the other 20 had bilateral or side-shifting pain during attacks. Both migraine subgroups (bilateral and unilateral) showed significantly lower thresholds compared with controls. The lowest values were observed on the symptomatic side of unilateral migraine patients. These findings suggest that sensorimotor mechanisms and/or pain control systems at the trigeminal level are impaired in migraine. The bilateral location of these abnormalities seems to point to a centrally located dysfunction.

Role of the central endogenous opiate system in patients with syndrome X

BACKGROUND

To evaluate the role of the endogenous opioid system (EOS) in abnormal pain perception in patients with syndrome X, we used a neuroendocrine approach, evaluating plasmatic luteinizing hormone (LH) changes after naloxone, a competitive antagonist of opioid receptors able to unblock tonic EOS inhibition on gonadotropin release. Thus LH response to naloxone test indicates the central EOS activity on hypothalamic luteinizing hormone-releasing hormone (LH-RH) inhibitory opioid receptors.

METHODS

Ten patients with syndrome X, 10 age-matched male patients with coronary artery disease (CAD), and 10 normal subjects were analyzed. Naloxone tests were performed between 8 and 9 am. Basal beta-endorphin and LH levels were determined on 4 blood samples at 20-minute intervals; after naloxone (0.1 mg/kg intravenously in 4 minutes), LH was measured on 8 samples at 15-minute intervals. In all patients the test was also performed after LH-RH administration. Anginal pain on exercise testing was subjectively scored on a 1 to 10 analogic scale and wall motion abnormalities were quantified by a wall motion score index.

RESULTS

Significant differences were found in LH release after naloxone (CAD 260.3 +/- 42.6 vs syndrome X 151.6 +/- 48.5 mIU/mL, P <.05), angina score (CAD 5.5 +/- 1.3 vs syndrome X 7.2 +/- 1.7, P <.05), and wall motion abnormalities (CAD 3.6 +/- 1. 2 vs syndrome X 2.8 +/- 1.9, P <.05).

CONCLUSIONS

The reduced LH release after naloxone in syndrome X, with a normal LH-RH response, suggests a lower central EOS activity, which may be related to the higher anginal pain perception.

Effect of sulpiride or paroxetine on cerebrospinal fluid neuropeptide concentrations in patients with chronic tension-type headache

In lumbar cerebrospinal fluid (CSF) obtained from patients with chronic tension-type headache (CTH), the concentrations of beta-endorphin, met-enkephalin, dynorphin, cholecystokinin (CCK), calcitonin gene-related peptide (CGRP), and somatostatin were measured before and after 8 weeks of treatment with sulpiride or paroxetine. We previously reported higher than normal met-enkephalin concentrations in CTH. The present study reveals normal basal concentrations of CCK, CGRP and somatostatin and slightly decreased dynorphin in the same patients. Treatment with sulpiride or paroxetine did not change the concentration of any of the neuropeptides measured. These data suggest central changes in opioid systems but not in other peptide systems (CCK, CGRP, somatostatin) involved in nociceptive processing at the level of the spinal cord dorsal horn/nucleus caudalis of the trigeminal nerve in CTH. Such central changes might be pathophysiologically important or merely secondary to other more important occurrences. The lack of changes in neuropeptide concentrations during drug treatment makes planning of studies involving CSF analysis easier, but also limits the probability of obtaining information on specific neuropeptide systems through CSF analysis.

A review of hormonal findings in cluster headache. Evidence for hypothalamic involvement

The cause of cluster headache remains to be determined. The involvement of peripheral neurovascular structures can explain the pain and autonomic signs of a cluster attack, but not its rhythmicity. The central theory of cluster headache attributes the cyclic recurrence to involvement of the hypothalamus. To evaluate hypothalamic dysfunction a number of hormone studies have been carried out on cluster headache patients. Alterations in plasma melatonin, cortisol, testosterone, gonadotrophins, prolactin, growth hormone and thyrotropin have been documented, some only in the cluster period but others in the remission phase of the illness. We believe that the hormonal abnormalities in cluster headache support disorders of hypothalamic function.

Plasma and cerebrospinal fluid beta-endorphin in chronic tension-type headache

Previous studies have provided evidence of an increased sensitivity to pain, a decreased hypothalamic opioid tone, and decreased cerebrospinal fluid (CSF) beta-endorphin (beta-EP) concentration in patients with primary chronic headache. We applied separate specific radioimmunoassays for beta-EP in CSF and plasma on samples from age-matched controls and a group of 50 patients with chronic tension-type headache (CTH) fulfilling the diagnostic criteria set by the International Headache Society. Median CSF beta-EP concentrations (95% confidence limits) were 12.8 pmol/l (11.0-14.5) in CTH patients and 11.9 pmol/l (10.9-14.2) in the control group, which is not significantly different (P = 0.28). Plasma beta-EP concentrations did not differ either, being 3.1 pmol/l (2.4-3.7) and 3.3 pmol/l (1.8-4.0) in the patients with CTH and in controls, respectively (P = 0.88). Plasma and CSF beta-EP concentrations did not correlate. Reversed-phase high performance liquid chromatography (HPLC) of CSF pools from the headache patients and controls revealed similar profiles of beta-EP-immunoreactivity both when C-terminally and N-terminally directed antisera were used, suggesting a normal post-translational processing of the pro-opiomelanocortin gene in patients with CTH. beta-EP is not involved in the pathogenesis of CTH, or such a role is not reflected in CSF or plasma concentrations of the neuropeptide.

Endogenous opioid system modulation in anginal pain: demonstration of its central activity

Plasma beta-endorphin levels provide controversial results on the role of endogenous opioid system in modulation of anginal pain. As an alternative, the action of plasmatic luteinizing hormone after administration of naloxone was investigated: naloxone blocks the tonic endogenous opioid system inhibition of gonadotropin release; thus, the level of luteinizing hormone after naloxone administration is an index of central endogenous opioid system activity. Twenty patients with coronary artery disease and positive results of stress tests were selected: 10 had angina (group I) and 10 did not (group II). Ten healthy subjects were also studied as a control group (group III). In all patients basal plasma beta-endorphin levels, basal luteinizing hormone plasma levels (every 15 minutes for 1 hour) and luteinizing hormone plasma levels after administration of 0.1 mg/kg naloxone over 4 minutes (every 15 minutes for 2 hours) were determined. In 15 patients the test was performed after luteinizing hormone releasing hormone was given. The integral concentration time of luteinizing hormone plasma level during baseline (LHiB) and after administration of naloxone (LHiN) or luteinizing hormone releasing hormone (LHiRH), the ratio (LHiN:LHiB and LHiRH:LHiB) and the differences (LHiN-LHiB and LHiRH-LHiB) between the postinfusion period and baseline were calculated. No difference was found in beta-endorphin plasma levels and luteinizing hormone response after luteinizing hormone releasing hormone infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

The insulin tolerance test and the ovine corticotrophin-releasing hormone test in episodic cluster headache

Clinical observations indicate a central nervous system, probably hypothalamic, involvement in cluster headache pathogenesis. In order to investigate the supposed hypothalamic involvement in cluster headache, we followed the hypothalamic-pituitary-adrenal axis and autonomic responses to the insulin tolerance test and the ovine corticotrophin-releasing hormone test in episodic cluster headache patients, both during remission and during the cluster period. The study revealed increased basal cortisol levels in all cluster patients. A blunted cortisol response to ovine corticotrophin-releasing hormone, in spite of a normal ACTH surge, was subsequently found in both illness phases. These findings suggest hypothalamic-pituitary-adrenal axis hyperactivity in both cluster phases. Furthermore, reduced ACTH and cortisol responses after insulin challenge were also observed in both remission and cluster period patients; a reduced norepinephrine surge was seen only in the cluster period. Taken together, these results suggest a hypothalamic involvement in the altered neuroendocrinological and autonomic responses found in our patients.

Opioid control of the hypothalamus-pituitary-adrenal axis cyclically fails in menstrual migraine

To assess the biological correlates of the precipitation of migraine attacks in the perimenstrual period, plasma beta-endorphin (beta-EP) and cortisol responses to naloxone (8 mg iv) and corticotropin releasing hormone (100 micrograms iv) were evaluated in both the follicular phase and the premenstrual period in 7 patients suffering from menstrual migraine and in 7 healthy, asymptomatic control volunteers. In the controls, naloxone evoked a significant release of both beta-EP (F = 5.86, p less than 0.002) and cortisol (F = 4.43, p less than 0.008), independently of the menstrual cycle phase (F = 0.31 and 1.04, for beta-EP and cortisol, respectively). Menstrual migraine patients, on the other hand, showed a significant hormone response only in the follicular phase, not in the premenstrual period. Corticotropin releasing hormone significantly increased beta-EP and cortisol in both the controls and the menstrual migraine patients, independently of the menstrual cycle phase. In both the naloxone and corticotropin releasing hormone testings, the basal beta-EP levels measured in the premenstrual period were lower than those observed in the follicular phase (p less than 0.02). These data demonstrate a cyclical, premenstrual dysfunction of the hypothalamic control exerted by opioids on the hypothalamus-pituitary-adrenal axis. Impairment of this fundamental adaptive mechanism (involved in stress responses and in pain control) could establish a causal relationship between menstrual-related migraine attacks and premenstrual opioid hyposensitivity.

Endogenous opiates: 1988

This paper is the eleventh installment in our annual review of the research during the past year involving the endogenous opiate system. It is concerned with nonanalgesic and behavioral studies of the opiate peptides that were published during 1988. The specific topics this year include stress; tolerance and dependence; eating; drinking; gastrointestinal, renal, and hepatic functions; mental illness; learning, memory, and reward; cardiovascular responses; respiration and thermoregulation; seizures and other neurological disorders; electrical activity; locomotor activity; sex, pregnancy, and development; immunology and cancer; and other behavior.

Neuroendocrine evidence of deranged noradrenergic activity in chronic migraine

Migraine is a psychobiological disorder in which a recurrent failure of opioid and adrenergic systems might occur, as plasma and CSF studies suggest. In order to elucidate the relationship between noradrenergic and opioidergic functions, the plasma beta-endorphin (beta-EP) response to clonidine and the cortisol response to dexamethasone were evaluated together in 25 patients suffering from migraine without aura, and with chronic tension headache (MTH). Baseline beta-EP plasma levels and beta-EP response to clonidine were significantly lower in MTH subjects than in controls, suggesting a postsynaptic hypothalamo-pituitary impairment. Forty-four percent of the MTH subjects showed either a lack of suppression of plasma cortisol following dexamethasone administration, or basal cortisol concentrations higher than controls and suppressors, suggesting a disinhibition of the hypothalamopituitary-adrenal (HPA) axis. An inverse correlation was found between pain severity and beta-EP secretion induced by clonidine (delta max), and no relationship was found between beta-EP and mood. These data suggest a failure of central noradrenergic activity, or perhaps an impaired secretion of beta-EP not related to HPA axis hyperactivity or to affective state.