萊克多巴胺 láikèduōbā'àn ractopamine Origin Definitions Defs Strokes Stroke Words Sentences Sents 莱 lái phonetic 克 kè phonetic 多巴胺 duōbā'àn noun dopamine A neurotransmitter in the brain that is responsible for transmitting signals related to pleasure and excitement; abnormal levels can lead to Parkinson's disease or other conditions.