“…A broad variety of neurotransmitters has been found in the insect ENS, e.g., various peptides (Copenhaver and Taghert, 1989a;Duve and Thorpe, 2003;Hill and Orchard, 2003;Clark et al, 2006), GABA (Luffy and Dorn, 1992;Trumm and Dorn, 2000), acetylcholine (Bicker et al, 2004), and serotonin (Davis, 1985;Klemm et al, 1986;Radwan et al, 1989;Luffy and Dorn, 1992;Molaei and Lange, 2003). Serotonergic neurons form a large group among ENS neurons.…”