DOPA decarboxylase activity in the nervous system and the ctenidium of the freshwater clam, Musculium (Sphaerium) transversum.
Dopa decarboxylase was measured in ganglia, connectives, branchial nerve and ctenidium of the clam, Musculium transversum. DOPA decarboxylase inhibitors (STH, HMD, and alpha-methyl-DOPA) reduced the enzymatic activity in all extracts. Ligation and extirpation of the visceral ganglion and branchial nerve significantly decreased the enzymatic activity in the ctenidium. Scanning electron microscopic observations showed numerous degenerative changes in nerve cells with progressive destruction of axons within the branchial nerve. In conclusion, it appears that lateral ctenidial cilia are dependent upon the decarboxylase activity of the visceral ganglion and branchial nerve.