Journal of Neuroscience, Vol 7, 343-356, Copyright © 1987 by Society for Neuroscience
The toxic effects of ethylcholine mustard aziridinium ion on cholinergic cells in the chicken retina
TJ Millar, I Ishimoto, M Boelen, ML Epstein, CD Johnson and IG Morgan
The chicken retina has been used to examine the toxicity of a highly
reactive chemical analog of choline, ethylcholine mustard aziridinium ion
(ECMA). Following a single intravitreal injection, retinas were analyzed
biochemically for CAT and AChE activities, and GABA, glycine, and dopamine
levels. Retinas were also examined using histofluorescence for dopamine
histochemistry, for AChE, and immunohistochemistry with antibodies to CAT,
tyrosine hydroxylase, GABA, 5-HT, Leu-enkephalin, and somatostatin. A dose
of 50 nmol ECMA caused a prolonged 70% depletion of CAT activity and a 40%
depletion of AChE activity. The other biochemical parameters were
unchanged. This result corresponds to the morphological finding that 2
populations of cholinergic cells were destroyed and that the AChE activity
associated with their terminal arbors was lost. A third population of
cholinergic cells, located towards the middle of the inner nuclear layer,
was resistant to the toxic effects of ECMA. The other cell types, except
for somatostatin- immunoreactive cells and photoreceptors, which showed
transient effects, were unaffected. ECMA therefore appears to be a highly
specific toxin for cholinergic cells in the retina.