Receptor for both octopamine and tyramine, invertebrate neurotransmitters, and neuromodulators. The activity of this receptor is mediated by G proteins which activate adenylyl cyclase. The rank order of potency for agonists is tyramine > octopamine > dopamine > epinephrine > norepinephrine > serotonin > histamine. For antagonists, the rank order is yohimbine > chlorpromazine > phentolamine > mianserine > cyproheptadine > dihydroergotamine > clonidine > synephrine. Tyramine has a functional role in the olfactory system as a neurotransmitter or a neuromodulator. Preferentially expressed in Drosophila heads. Belongs to the G-protein coupled receptor 1 family.