Synthesis of 3H-acetylcholine in the rabbit lacrimal gland and its release by electrical field stimulation.

Electrical field stimulation was applied to the rabbit lacrimal gland during incubation in vitro with 3H-choline, after which the efflux of tritiated metabolites was studied. In the presence of physostigmine 3H-acetylcholine was released into the incubation medium when the gland was stimulated electrically. The identity of the 3H-acetylcholine synthesized by the preparation was established by its identical ion exchange chromatographic properties to native acetylcholine. The tissue contents of 3H-acetylcholine and 3H-choline were 14.4 and 3.6%, respectively, of the total activities found in the gland. This study demonstrates that the rabbit lacrimal gland is innervated cholinergically. It is suggested that the method developed might be of value for studying effects of drugs on cholinergic neurotransmission in this organ.