4617
We studied 18 dogs , anaesthetised and spontaneously breathing both room air and after the inhalation of a gas mixture containing 10 % CO2 , 20 . 9 % O2 , and 69 . 1 % N2 , to determine the role of histamine , serotonin , and acidaemia in pulmonary hypertension produced by hypercapnia .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
Answer:
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