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.
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Question: Central effects of fexofenadine and cetirizine: measurement of psychomotor performance, subjective sleepiness, and brain histamine H1-receptor occupancy using 11C-doxepin positron emission tomography.

Answer: histamine H1-receptor


Question: The antitussive activity of delta-opioid receptor stimulation in guinea pigs.

Answer: delta-opioid receptor


Question: Dominant expression of mRNA for prostaglandin D synthase in leptomeninges, choroid plexus, and oligodendrocytes of the adult rat brain.

Answer:
prostaglandin D synthase