Neonatal 6-hydroxydopamine treatment increases the vulnerability of the blood-brain barrier to acute hypertension in conscious rats.
Acute hypertension increases the cerebrovascular permeability to protein to a higher extent in anesthetized than in conscious rats. When hypertension is combined with a pronounced cerebral vasodilatation, e.g. in bicuculline-induced seizures, the protein leakage is enhanced. Conscoius, unrestrained 2--3-months-old rats received adrenaline or bicuculline i.v. during continuous recording of the mean arterial pressure and were killed 3 minutes later. Rats, neonatally sympathectomized by 6-hydroxydopamine, had significantly increased extravasation of 125I serum albumin in the brain after adrenaline-induced hypertension than nonsympathectomized rats. Since transection of the cervical sympathettic trunk alone does not have the same effect, a protection of the blood-brain barrier in acute hypertension in conscious rats may, at least in part, be mediated via the central noradrenergic innervation of cerebral vessels. Bicuculline did not increase blood pressure in 6-OHDA treated rats; thus the blood-brain barrier remained intact.
D000208:Acute Disease; D000818:Animals; D000831:Animals, Newborn; D001640:Bicuculline / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D001812:Blood-Brain Barrier / Q000187:drug effects; D002199:Capillary Permeability / Q000187:drug effects; D002536:Cerebral Arteries / Q000294:innervation; D004837:Epinephrine / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D006892:Hydroxydopamines / Q000494:pharmacology*; D006973:Hypertension / Q000139:chemically induced / Q000503:physiopathology*; D051381:Rats; D012711:Serum Albumin, Radio-Iodinated; D013564:Sympathetic Nervous System / Q000187:drug effects*
D006892:Hydroxydopamines; D012711:Serum Albumin, Radio-Iodinated; D001640:Bicuculline; D004837:Epinephrine