574
However , the network consequences of a commonly used approach to augment tonic GABAA receptor - mediated conductances by global manipulation of extracellular GABA are difficult to predict without understanding how epileptogenesis alters the pharmacology and GABA sensitivity of tonic inhibition , and how manipulation of tonic conductances modulates the output of individual neurons .
 Chemical: GABA; Chemical: GABA
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: GABA; Chemical: GABA