Biochemical evidence for cholinergic activity in retinal blood vessels.

摘要: Blood vessels from human, cat, pig and bovine retinas were analyzed for their contents of choline acetyltransferase (ChAT) muscarinic binding sites. ChAT was measured by the synthesis 3H-acetylcholine in presence 3H-acetyl CoA choline. Muscarinic sites determined specific 3H-quinuclidinyl benzylate (3H-QNB). Tissue levels varied 39-850 nmol/g/hr, lowest values being human tissues. less different (0.5 to 1.8 fmol/mg net weight) among species studied, highest retinal vessels. It appears that blood not only have bind acetylcholine, perhaps mediate physiologic responses, but might be capable supplying acetylcholine local vascular tone control.