Abstract
Many neurons contain multiple cotransmitters, including neuropeptides. In the stomatogastric nervous system a number of different neuropeptides are found colocalized with small molecule neurotransmitters. Three proctolin-containing projection neurons contain different cotransmitters, and modulate the stomatogastric ganglion motor patterns differently. A number of neuropeptides, including proctolin, found in inputs to the stomatogastric ganglion, converge onto the same membrane current. This includes colocalized peptides. Studying the peptidergic modulation of the stomatogastric ganglion provides a unique opportunity to uncover general principles of organization of peptidergic control systems.