In this task, you are given a sentence. You are expected to recognize the name of any form of chemical substances. Although there might be several correct answers, you need to write one of them.
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Question: Neuronal expression of glucosylceramide synthase in central nervous system regulates body weight and energy homeostasis.

Answer: glucosylceramide


Question: Study of the nematode putative GABA type-A receptor subunits: evidence for modulation by ivermectin.

Answer: GABA


Question: Comprehensive review of rasagiline, a second-generation monoamine oxidase inhibitor, for the treatment of Parkinson's disease.

Answer:
monoamine