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.

 Nicotinic receptor antagonists mecamylamine ( 0 . 5 and 1 mg / kg ) and hexamethonium ( 5 and 10 mg / kg ) reduced the response induced by nicotine ( 0 . 25 mg / kg ) .
Nicotinic receptor