G. Sanchezchavez et al., ACETYLCHOLINESTERASE AND BUTYRYLCHOLINESTERASE ACTIVITIES IN THE RAT RETINA AND RETINAL-PIGMENT EPITHELIUM, Journal of neuroscience research, 41(5), 1995, pp. 655-662
The acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activ
ities in the neural retina and retinal pigment epithelium (RPE) of adu
lt rats were determined, The tissues were extracted with a saline buff
er to release the soluble enzymes (S-1) and the pellet re-extracted wi
th Triton X-100 to detach the membrane-bound enzymes (S-2). Less than
5% of the cholinesterase activity measured in retina and almost 30% of
that assayed in RPE was due to BChE. About 20% and 10% of the AChE in
retina and RPE was brought into solution with a saline buffer and the
rest with a detergent-containing buffer. Main AChE molecular forms of
10.5S (hydrophilic G(4)(H)), 9.5S (amphiphilic G(4)(A)) and 3.0S (amp
hiphilic G(1)(A)) were identified in retina by subjecting the supernat
ant S-1 to sedimentation analysis in sucrose gradients made with Brij
96. Amphiphilic G(4) and G(1) AChE were found in S-2. Analysis of the
soluble fractions obtained from RPE in the gradients made with Brij 96
revealed 16.0S (asymmetric A(12)), 10.5-10.0S (globular G(4)(H) + G(4
)(A)), 4.5S (G(2)(A)), and 3.0S (G(1)(A)) AChE forms in S-1, whereas G
(4)(A) G(2)(A), and G(1)(A) enzyme molecules predominated in S-2. Our
results show that amphiphilic tetramers and monomers of AChE are abund
ant in neural retina, and enzyme tetramers, dimers, and monomers in RP
E. The AChE in the neural retina might be involved in cholinergic acti
ons. epithelium remains to be established. (C) 1995 Wiley-Liss, Inc.