Octopamine (OA) and tyramine (TA) are the invertebrate counterparts of the vertebrate adrenergic neurotransmitters.They regulate various physiological functions in insects, such as endocrine secretion, foraging, egg-laying, fight and flight, and learning and memory.Octopamine and tyramine exert their effects by binding to specific receptor proteins that belong to the superfamily of G-protein coupled receptors.