Effect of chemical sympathectomy on the content of acetylcholine, choline and choline acetyltransferase activity in the cat spleen and iris.

1. Acetylcholine and choline were measured in the spleens and irides of normal and 6-hydroxydopamine-treated cats. In addition, choline acetyltransferase activity was measured in the spleens.2. No acetylcholine or choline acetyltransferase activity were found in spleens of normal or treated cats. The choline content of normal spleens was 12.4 +/- 1.5 mug/g wet wt. (mean +/- S.E. of mean), which was not significantly altered by chemical sympathectomy.3. The acetylcholine and choline contents of the cat iris were 3.0 +/- 0.3 mug/g wet wt. and 7.7 +/- 0.9 mug/g wet wt., respectively. There was no difference in acetylcholine and choline concentrations between left and right or normal and sympathectomized irides.4. These results are discussed in relation to the question of a cholinergic link in post-ganglionic sympathetic transmission.