Sentence:  The Mecholyl and noradrenalin tests applied with certain precautions are reliable indicators of this central autonomic balance , but for the sake of correlating autonomic and clinical states , and of studying the effect of certain therapeutic procedures on central autonomic <WSD>reactions</WSD> , additional tests seem to be desirable . 
Meaning of the word marked with <WSD> tags:  a bodily process occurring due to the effect of some antecedent stimulus or agent