17964
This study examined the influence of the COMT Val158Met polymorphism on subjective , physiological and cognitive effects of intravenous ( IV ) nicotine use in African Americans ( AAs ; n = 56 ) and European Americans ( EAs ; n = 68 ) smokers .
 Chemical: nicotine
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: nicotine