Physiological effects of Protogonyaulax tamarensis on cardiac activity in bivalve molluscs

Abstract

1. In Spisula solidissima, Mercenaria mercenaria, Artica islandica, and Placopecten magellanicus, there was no effect on cardiac activity after exposure to Protogonyaulax tamarensis (GT429). 2. In Mya arenaria, there was transient cardiac inhibition in 40% of the individuals tested after exposure to GT429. 3. In Ostrea edulis there was long term decrease in heart rate in 22% of the animals after exposure to GT429. 4. In Geukensia demissa, there was transient cardiac inhibition in 10% of the animals, transient excitation in 40%, and long term inhibition in 10% after exposure to GT429. 5. In Mytilus edulis, there was transient inhibition in 25% of the animals, long term inhibition in 21% and long term excitation in 11%, after exposure to GT429. 6. There was no difference in the distribution of responses in between Mytilus that had prior exposure to GT429 and Mytilus that had no prior exposure.