Neurotransmitters, neuromodulators, and neurohormones.
D004723:Endorphins / Q000494:pharmacology; D004745:Enkephalins / Q000494:pharmacology; D006801:Humans; D009420:Nervous System / Q000187:drug effects*; D009469:Neuromuscular Junction / Q000502:physiology; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000502:physiology; D013569:Synapses; D009435:Synaptic Transmission
D004723:Endorphins; D004745:Enkephalins; D018377:Neurotransmitter Agents; D017981:Receptors, Neurotransmitter