2066
The stimulant action of nicotine was blocked by the central nicotinic antagonist mecamylamine but not by the peripheral nicotinic blocker hexamethonium , indicating that the response is probably mediated by central nicotinic receptors .
 Chemical: nicotine; Chemical: mecamylamine; Chemical: hexamethonium
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
 Entities: nicotine, mecamylamine, hexamethonium 
Answer:
 Chemical: nicotine; Chemical: mecamylamine; Chemical: hexamethonium