Nitroglycerine is known to induce a headache attack in cluster headache patients, which is indistinguishable from a spontaneous attack. It has recently been suggested that a release of calcitonin gene-related peptide (CGRP) from peripheral terminals of trigeminal nociceptive neurons, which supply cephalic blood vessels, underlies symptoms of cluster headache. The aim of this study was to investigate whether the provocative action of nitroglycerine in cluster headache is due, at least in part, to activation of the trigeminovascular system. Nineteen subjects suffering from episodic cluster headache participated in the study. Eleven of them were in an active period, whilst the others were in remission at the time of the study. CGRP-like immunoreactivity (CGRP-LI) was measured in blood samples from the extracerebral circulation before and after the sublingual administration of nitroglycerine. Baseline CGRP-LI plasma levels were higher (P < 0.05) in the patients who were in an active period. Only in these patients did nitroglycerine induce an attack, which was preceded by a latent period with a mean duration of 27 +/- 3 min. When compared with the baseline, a significant (P < 0.01) increase in plasma CGRP-LI was detected at the peak of the provoked attack; no such increase was detected during the latent period, or at the onset of the attack. The results of this study suggests that the provocative action of nitroglycerine in cluster headache is due, at least in part, to activation of the trigeminovascular system. This mechanism seems to be slow and unrelated to the well-known rapidly occurring vasodilator effects of the drug. Finally, activation of the trigeminovascular system only occurs in those patients already in an active cluster headache period who also have high basal CGRP-LI plasma levels. This suggests that a hyperactivity of trigeminal nociceptive fibres could make the trigeminovascular system of these patients sensitive to the triggering action of nitroglycerine.

The circannual secretion of melatonin in 14 Swedish and 15 Italian patients suffering from episodic cluster headache was compared with 14 Swedish and 15 Italian healthy controls matched for sex and age. Overnight samples of urine were collected once a month from 8 to 14 months and kept at -20 degrees C until analysed with RIA. The melatonin concentrations in nocturnal urine were permanently low in cluster headache and there was no consistent change of the melatonin concentration in relation to cluster periods occurring during the study. There was no definitive circannual or infraannual rhythmicity of melatonin in patients or controls. Multiple analysis of variance with repeated measurements showed a significant effect of disease (p < 0.05), but not of time. Sex, geographical location, age, and smoking also had significant effects (p < 0.001) on the melatonin concentrations. Lower melatonin levels in cluster headache patients than in controls may in part be related to a larger number of smokers in the patient group. The relation between tobacco use and melatonin should be further studied.

The pain relieving effect of somatostatin treatment during 72 attacks of cluster headache in 8 male patients was compared to treatment with ergotamine or placebo in a double-blind study. Infusion of somatostatin (25 micrograms/min for 20 min i.v.) reduced the maximal pain intensity and the duration of pain significantly compared to placebo treatment, and to a degree comparable to ergotamine tartrate treatment (250 micrograms i.m.). The results obtained provide new information concerning the possible mechanism of cluster headache attacks and suggest a new therapeutic approach.

1 Topical application of capsaicin to the human nasal mucosa induced a burning sensation and sneezing. A dose-dependent seromucous nasal secretion was also observed. Capsaicin (75 jig) was more potent than methacholine (50 mg) in producing nasal secretion, while topical histamine (200 jg

A multicenter study was carried out in 10 Italian Headache Centers to investigate the prevalence of psychosocial stress and psychiatric disorders listed by the IHS classification as the "most likely causative factors" of tension-type headache (TTH). Two hundred and seventeen TTH adult outpatients consecutively recruited underwent a structured psychiatric interview (CIDI-c). The assessment of psychosocial stress events was carried out using an ad hoc questionnaire. The psychiatric disorders that we included in the three psychiatric items of the fourth digit of the IHS classification were depressive disorders for the item depression, anxiety disorders for the item anxiety, and somatoform disorders for the item headache as a delusion or an idea. Diagnoses were made according to DSM-III-R criteria. At least one psychosocial stress event or a psychiatric disorder was detected in 84.8% of the patients. Prevalence of psychiatric comorbidity was 52.5% for anxiety, 36.4% for depression, and 21.7% for headache as a delusion or an idea. Psychosocial stress was found in 29.5% of the patients and did not differ between patients with and without psychiatric comorbidity. Generalized anxiety disorder (83.3%) and dysthymia (45.6%) were the most frequent disorders within their respective psychiatric group. The high prevalence of psychiatric disorders observed in this wide sample of patients emphasizes the need for a systematic investigation of psychiatric comorbidity aimed at a more comprehensive and appropriate clinical management of TTH patients.