Cerebrovascular response to infused 5-hydroxytryptamine in the baboon. Part 2. 5 Hydroxytryptamine infusion in estrogen and progesterone treated animals

Receptor changes in cerebral arteries after subarachnoid haemorrhage

Subarachnoid haemorrhage (SAH), occurring with a delay of 4-10 days is linked to cerebral vasospasm (CVS), a pathological constriction of the cerebral arteries. Several agents have been suggested as being responsible - amongst these perhaps 5-hydroxytryptamine (5-HT) and endothelin-1 (ET-1) are the most prominent, given their ability to elicit powerful constriction of arteries. Investigating both 5-HT and ET receptors we observed distinct changes in the receptor phenotype after experimental SAH - namely upregulation of the ETB and 5-HT1B receptors - linked to a higher sensitivity to the endogenous agonists. This multiple receptor upregulation may explain the failure in treating CVS using single receptor antagonists, and may also significantly change our understanding of the effector mechanism behind CVS. So far only the ET and 5-HT receptors have been studied in this regard, but other receptor systems may also undergo changes.

Neurotologic findings in basilar migraine

Treatment of a patient with otologic symptoms and associated migraine-like headache presents the otolaryngologist with formidable problems. Although clinical practice and scientific publications recognize their frequent association, relationships have yet to be well defined. This study seeks to add order to disarray by delineating symptoms and signs of a clearly identified group of migraine patients. Fifty patients with well-defined basilar migraine underwent a thorough neurotologic examination, as well as comprehensive auditory and vestibular testing. Patients were selected from 5880 patients seen over a 2-year period and were prospectively entered into the study after detailed questionnaires and testing were completed for each patient. The most common symptoms found were dysequilibrium, phonophobia, and head pressure. The most common signs were positional nystagmus, low-frequency hearing loss, abnormal loudness discomfort level, and an abnormality on caloric examination. Advanced vestibular testing showed abnormal amplitude scaling, abnormal toes-down pertubation, and an abnormal sway (condition 6) on dynamic posturography. There was frequently an asymmetry on computerized rotation. The author concludes that the majority of patients have subtle findings on testing, but a few have severe peripheral injury due to the basilar migraine. Findings are consistent with the theory that basilar migraine is a central nervous system maladaptation syndrome which creates otoneurologic symptoms and, in a small percentage of cases, may injure the peripheral end-organ.

Ovarian steroid levels in migraine with and without aura

Radioimmunoassays were used to measure interictal levels of ovarian steroids (oestradiol, total oestrogens and progesterone) in migraine patients at the onset of menses and coincident with the luteinizing hormone surge preceding ovulation. Results of these verified biochemically-contrasting points of the ovarian cycle were used to compare 13 migraine patients without aura and 6 migraine patients with aura with 17 non-migraine women. No group differences were found for physiological basal levels of ovarian steroids measured at menses. Preceding ovulation elevation in oestradiol levels relative to normal was found in migraine patients with aura but not in migraine patients without aura. These results suggest that a variation in oestradiol levels is an important factor in the different clinical expressions of migraine.

The role of estrogen in migraine: a review and hypothesis

The epidemiological, clinical and basic science evidence for a role of estrogen in migraine is reviewed. The hypothesis is put forward that estrogen exerts its influence by modulating sympathetic control of the cerebral vasculature.

The effect of intracarotid infusion of dexamethasone and 5-hydroxytryptamine on cerebral blood flow and metabolism in baboons

The effect of intracarotid infusion of dexamethasone on cerebral blood flow and cerebral oxygen utilization was measured in baboons using the xenon-133 clearance technique. The cerebrovascular response to intracarotid infusion of 5-hydroxytryptamine (5-ht) was then determined during simultaneous infusion of the steroid. Infusion of dexamethasone alone and infusion with 5-HT produced no significant change in cerebral blood flow or cerebral oxygen utilization when compared to baseline values. The study indicates that neither dexamethasone nor 5-HT with dexamethasone modify cerebral blood flow when infused via the internal carotid artery.