Interaction of dopamine and cardiac sac modulatory inputs on the pyloric network in the lobster stomatogastric ganglion.

Dopamine and cardiac sac network activity each have strong, and different, modulatory actions on the pyloric rhythm in the stomatogastric ganglion of the spiny lobster. When combined, the two modulatory inputs have a complex effect. Dopamine and cardiac sac activity cancel one another's effects to restore normal pyloric activity to 4 of the 6 classes of pyloric neurons. In the remaining two pyloric neurons, dopamine's strong modulatory effects are completely overruled during cardiac sac network related activity. Possible cellular mechanisms underlying these interactions are discussed.