Fig. 3.

Effects of bath-applied dopamine (DA), serotonin (5HT), and octopamine (Oct) on the AB neuron, when isolated from all pyloric synaptic inputs as described in Materials and Methods, with descending modulatory inputs in the stomatogastric nerve blocked (A) or left intact (B).Filled bars, AB cycle frequency; open bars, mean spike frequency within the AB burst. The data show the mean of three (A) or five (B) different preparations ± SD. InA, both parameters measured in Oct (*) are significantly different from DA and 5HT frequencies. Both parameters measured in all three amines in B (*) are significantly different from control. In addition, the measurements in Oct are significantly different from those in DA (**).