Forty-five patients with cluster headache in the asymptomatic phase were studied by electronic pupillography, testing autonomic function of both pupils pharmacologically. Topical sympathetically-acting mydriatics, tyramine and cocaine and the cholinoceptor blocker, homatropine, induced defective mydriatic responses on the symptomatic side, indicating latent impairment of sympathetic function. The abnormality was found in interattack intervals of the cluster period or during intercluster phases. The tyramine test can be proposed for objective diagnosis of cluster headache. We postulate that cluster attacks are triggered and lateralized by a permanent latent unilateral sympathetic dysfunction. Lithium reduced the mydriatic response to tyramine of the pupil contralateral to the pain, thus restoring the equilibrium between both pupils; this therapy may correct the asymmetric sympathetic function by attenuating the activity in the asymptomatic side.

Nicotinamide has been recently introduced, in addition to intensive insulin therapy for patients with recent-onset insulin-dependent diabetes mellitus (IDDM) to protect beta cells from end-stage destruction. However, available data are conflicting. A double blind trial in 56 newly-diagnosed IDDM patients receiving nicotinamide for 12 months at a dose of 25 mg/kg body weight or placebo was designed in order to determine whether this treatment could improve the integrated parameters of metabolic control (insulin dose, glycated haemoglobin and C-peptide secretion) in the year after diagnosis. In addition to nicotinamide or placebo, patients received three to four insulin injections daily to optimize blood glucose levels. Patients treated with nicotinamide or placebo received similar doses of insulin during follow-up and 1 year after diagnosis with comparable glycated haemoglobin levels 6.7 +/- 1.8% nicotinamide vs 7.1 +/- 0.6% placebo). Basal and glucagon stimulated C-peptide secretion detectable at diagnosis were similarly preserved in the course of 12 months follow-up both in nicotinamide and placebo treated patients. No adverse effects were observed in patients receiving nicotinamide. When age at diagnosis was taken into account, nicotinamide treated older patients ( > 15 years of age) showed significantly higher stimulated C-peptide secretion than placebo treated patients (p < 0.02). These results suggest that nicotinamide can preserve and improve stimulated beta-cell function only in patients diagnosed after puberty.(ABSTRACT TRUNCATED AT 250 WORDS)

The pressor responsiveness to phenylephrine, an almost pure agonist of peripheral alpha-1-adrenoceptors, was studied in 32 migraine patients in headache-free intervals. Eighteen healthy volunteers served as a control group. Fourteen patients and 14 controls also underwent the tilt test. The following observations were made: (1) the pressor response to phenylephrine was significantly greater and longer lasting in patients than in controls; (2) the reflex decrease of heart rate did not differ in the two groups; (3) a normal orthostatic increase of blood pressure and heart rate occurred in migraineurs with hyperresponsiveness to phenylephrine. These findings suggest a supersensitivity of vascular adrenoceptors which is compatible with a chronic adrenergic deficiency in migraineurs. Since patients did not show an orthostatic hypotension in attack-free periods, the compensatory character of receptoral supersensitivity and the possible mechanisms of cardiovascular dysautonomia, which may occur during migraineous attack, were discussed.

SYNOPSIS Scotoma is the most frequent perceptive disturbance in migraine. Other visual, auditory, smelling and own body image distortions frequently occur, but they are seldom reported by patients unless specifically requested. The basic mechanism of these perceptive disorders as well as of pain is still unknown. Pentazocine, an agonist of s opiate receptors (mainly subserving the nervous structures involved in perceptive disturbances) provokes visual and own body image distortions in most migraine patients. In addition, naloxone (a specific opiate antagonist) prevents or reverts the perceptive disorders induced by pentazocine. Naloxone injected at the onset of the spontaneous scotoma interrupts the visual phenomena in most of classic migraineurs. When scotomata is interrupted by naloxone, even the headache intensity is usually reduced and the pain duration is shortened. In common migraine, naloxone administered after the onset of headache is ineffective on pain and extra‐pain phenomena.

Ten cluster headache patients and 10 healthy controls were subjected to electrocardiographic and pupillometric procedures in a search for cardiac and pupillary sympathergic asymmetry. Sympathergic stimulation was provoked by hyperventilation and by instilling tyramine into both eyes. In the control group, hyperventilation changed neither the T-wave form and polarity nor the QTc. Tyramine provoked an equal mydriasis on the two sides. In cluster headache sufferers, hyperventilation produced changes in the T-wave form and polarity as well as an increase of the QTc due to a disproportionate shortening of the R-R and Q-T intervals. An unequal mydriasis was noted after tyramine instillation due to less marked response on the symptomatic side. The observed electrocardiographic abnormalities are considered an expression of an asynchronous repolarization attributed to a sympathergic asymmetry. It is postulated that both the cardiac and pupillary sympathetic imbalance associated with cluster headache are central in origin.