<unk> s are a group of G-protein coupled receptors with<unk> s as ligands.  The endogenous<unk> s are dynorphins, enkephalins, endorphins, endomorphins and nociceptin/orphanin FQ. The<unk> s are ~40% identical to somatostatin receptors (SSTRs).
Opioid receptor
5-HT receptor
AMPA receptor
NMDA receptor
Muscarinic acetylcholine receptor
Baroreceptor
Nicotinic acetylcholine receptor
P2X receptor