Figure 1. Regulation of CREB activation in the SIA neurons.. In the presence of food, dopamine is released from the dopaminergic neurons and activates the dopamine receptor DOP-3 in the RIC neurons, possibly to decrease octopamine release. Dopamine also inhibits octopamine-mediated signaling in the SIA neurons through the dopamine receptors DOP-2 and DOP-3. In the absence of food, cessation of dopamine signaling results in octopamine-mediated CREB activation through the octopamine receptor SER-3. Exposure to water also induces CREB activation in the SIA neurons independently of dopamine and octopamine.