1. Cerebral Blood Flow and Metabolism
We succeeded in demonstrating the action potentials from the cerebral arterial walls in cats. Discharges of action potentials increased during induced hypotension and decreased during induced hypertension. Since fusaric acid (dopamine beta–hydroxylase inhibitor) suppressed the responses of action potentials to changes in blood pressure, the action potentials from the surface of cerebral arteries may have a close relation to the noradrenergic system.
To clarify the relationship between calcium metabolism and free radical during the reperfusion period following ischemia, we investigated the effect of superoxide dismutase (SOD) on changes in cytosolic free calcium. During reperfusion, the Ca2+ signal ratio remained at a high level in control group, while in the SOD–treated group, the Ca2+ signal ratio decreased. SOD may have ability to attenuate increases in intracellular calcium during the recirculation period following focal cerebral ischemia.
We investigated NO production in eNOS knockout (−/−) mice and nNOS knockout (−/−) mice during cerebral ischemia and reperfusion. NO production was continuously monitored by in vivo microdialysis. Levels of NO3− were significantly lower in eNOS (−/−) mice and nNOS (−/−) mice than in control mice during ischemia and reperfusion. NO3− levels were significantly lower in nNOS (−/−) mice than in eNOS (−/−) mice after the start of reperfusion. These in vivo data suggest that NO production in the striatum after reperfusion is closely related to activities of both nNOS and eNOS, and is mainly related to nNOS following reperfusion.
2. Migraine
The autonomic nervous function in patients with migraine was studied during headache–free intervals. Since migraine patients show sympathetic hypofunction together with denervation hypersensitivity of the iris and the arteries, a defective noradrenergic nervous system may play a role in the pathogenesis of migraine.
Migraine patients showed the lower level of plasma CGRP and SP compared to the normal volunteers. Migraine patients may have denervation hypersensitivity to CGRP and SP. Nitric oxide production following L–arginine infusion was enhanced in migraine patients.
Sweating function in patients with migraine was examined during headache–free intervals. After stimulated by intradermal injection of pilocarpine, molds of sweat droplets were obtained using Silastic. The number of droplets in classic migraine was significantly lower than that in the controls. Sweating function was impaired in patients with migraine.
When we investigated the sympathetic function during migraine attack, migraine patients showed the almost normal sympathetic function. These data suggested the sympathetic function of migraine patients will recover when patients have their attack.
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