Pain.
D000818:Animals; D001921:Brain / Q000503:physiopathology; D004723:Endorphins / Q000502:physiology*; D004745:Enkephalins / Q000502:physiology*; D006801:Humans; D010146:Pain / Q000503:physiopathology*; D013373:Substance P / Q000502:physiology
D004723:Endorphins; D004745:Enkephalins; D013373:Substance P