EFFECT OF SYMPATHETIC STIMULATION ON BLOOD-BRAIN BARRIER DYSFUNCTION INDUCED BY AMPHETAMINE AND BY EPILEPTIC SEIZURES

Stimulation of the sympathetic nerves to the brain is known to make the resistance vessels able to with stand a higher blood pressure, i.e. to prevent blood‐brain harrier (BBB) dysfunction and overpcrfusion in acute hypertension. When hypertension occurs concomitantly with a metabolic vasodilatation e.g. during epileptic seizures and after amphetamine‐administration, protein leakage in the brain is more pronounced than in hypertension per se. Unilateral stimulation of the cervical sympathetic chain during the administration of amphetamine or bicuculline—the latter a GABA‐receptor blocking substance that induces epileptic activity—attenuated the leakage of Evans blue‐albumin and 125IHSA into the brain. Our results thus indicate a prophylactic effect of sympathetic stimulation also when hypertension is combined with a nletabolically induced vasodilatation. The sympathetic nerves may constrict both extracerebral arteries and intracerebral resistance vessels. Unexpectedly the effect on the BBB of unilateral stimulation was to a great extent bi lateral under the present experimental conditions. © 1978 Scandinavian Physiological Society