In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.

[EX Q]: The antitussive activity of delta-opioid receptor stimulation in guinea pigs.
[EX A]: delta-opioid receptor

[EX Q]: Discovery of aryl ureas and aryl amides as potent and selective histamine H3 receptor antagonists for the treatment of obesity (Part I).
[EX A]: histamine H3 receptor

[EX Q]: The fidelity of transcription: RPB1 (RPO21) mutations that increase transcriptional slippage in S. cerevisiae.
[EX A]:
RPB1