Localization of NO-Synthase in Gonads of the Freshwater Bivalve Mollusc Nodularia vladivostokensis

Ultrastructural localization of NO-synthase in the gonad of the freshwater bivalve mollusc Nodularia vladivostokensis was studied. Individual NO-containing nerve fibers are revealed in the gonad wall. In the interacinar connective tissue, a high level of the enzyme activity is found in neurons and neural fibers. Reaction product in neurons is located in the nucleus, granular endoplasmic reticulum, on plasma membrane, and in the area of neuromuscular synapses. NO-containing granules are found in various nerve processes, but only cholinergic ones are identified.