Current concepts in the pathogenesis and interval treatment of migraine

Catecholamine content of cochlear and facial nerves. High-performance liquid chromatography analyses in normal and mutant mice

The catecholamine content in cochlear and facial nerves was determined using high-performance liquid chromatography coupled with electro-chemical detection. Minute amounts of norepinephrine were detected in both nerves in normal CBA/CBA mice and homozygotic jerker mouse mutants, whereas norepinephrine was found only in the facial nerve in the dancer heterozygotic mouse mutant. Dopamine and epinephrine were not detected in any of the mouse strains.

Responsiveness of isolated canine cerebral and peripheral arteries to ergotamine

Changes in tension of spiral strips from dog saphenous, external carotid and basilar arteries were monitored isometrically. Serotonin (5-HT) contracted the 3 arterial preparations in about the same concentration range. Compared with noradrenaline (NA) (100%) the efficacy of 5-HT was about 60% on saphenous, 150% on external carotid and about 500% on basilar arteries. Ergotamine (E) stimulated the 3 vascular preparations in concentrations about 100 times lower than 5-HT. Compared with NA the efficacy of E was about 20% on saphenous, 50% on external carotid and 200% on basilar arteries. Compared with 5-HT (100%) however, E had similar constrictor activities in the 3 arteries. It seemed likely therefore that 5-HT receptors are involved in the vasoconstrictor activity of E. Evidence for this was obtained in experiments in which cyproheptadine (Cy), a 5-HT antagonist, was used. For antagonism of E concentrations of Cy about 6 times higher than those required to inhibit 5-HT were necessary, whereas for antagonism of NA about 500 times higher Cy concentrations were necessary. The results suggest that on canine arterial vascular smooth muscle the constrictor activity of E is mediated mainly through serotoninergic receptor sites.