Dopa decarboxylase and average lateral ctenidial activity of the oyster Crassostrea virginica Gmelin: Response to salinity change and extirpation of portions of the nervous system

Abstract

1. 1. DOPA deearboxylase and yellow-autofluorescence of cytosomal pigments were measured in ganglia, connectives, nerve, and ctenidium of the oyster Crassostrea virginica. 2. 2. Enzymatic activity and amount of cytosomal pigment was higher in oysters at the habitat salinity of 30‰ 3. 3. Immediate change in the habitat salinity, in most cases, produced a decrease in decarboxylase activity in the ctenidium which could be correlated with a reduction in the average basal lateral ciliary rate. 4. 4. Extirpation of a neuronal component either changed levels of enzymatic activity in other members of the nervous system, ctenidium and/or average lateral beating rate before and after electrical stimulation of the branchial nerve. 5. 5. Extirpation coupled with a change in salinity from 30 to 10‰, further reduced the enzymatic activity and response to electrical stimulation mentioned above. 6. 6. In summary, decarboxylase activity levels decrease in response to sudden changes in salinity and removal of neuronal components. This decrease in enzymatic activity correlates with a significant reduction in average basal lateral ciliary rate on the ctenidium. The presence of higher decarboxylase activities and greater amounts of cytosomal pigments in 30‰ habitat animals.