Perivascular cholinesterase and morphological blood-brain barrier function.

Little is known about the function of cholinesterase activity present in the walls of cerebral microvessels. It has been shown that systemically administered physostigmine, a cholinesterase inhibitor that penetrates the blood-brain barrier, causes barrier opening. This has led to suggestions that perivascular cholinesterase is involved in the maintenance of morphological blood-brain barrier function. The present study demonstrates that the physostigmine-induced barrier opening is fully attributable to the acute hypertension and hypercapnia the agent gives rise to. Thus, it is discussed whether the enzyme activity may function as an enzymatic barrier to cholinergic agents.