The inhibition of choline acetyltransferase in guinea-pig cornea.

The effects of different compounds on the inhibition of choline acetyltransferase in guinea pig cornea have been studied. N-hydroxyethyl-4(naphthylvinyl)pyridinium bromide inhibited the enzyme in the cornea when a 0.5% solution was applied topically to the eye. The inhibition could not be explained by redistribution of the inhibitor after homogenization of the tissue. Inhibition of the enzyme was slowly reversed and nearly full enzyme activity was obtained when the eye was left intact for 48 hrs. N-methyl-4(naphthylvinyl)pyridinium bromide was a less efficient inhibitor in vivo and no inhibition was found with bromo acetonyl trimethylammonium bromide or acryloylcholine. Corneal ChAT was inhibited by the application of 3-methyl-5-methoxyphenyl pyridinium bromide, but the mechanism was obscured by the compound causing corneal oedema. The investigation shows that epithelium of the cornea can be used to test the in vivo effect of choline acetyltransferase inhibitors.