Sentence:  The Mecholyl and <WSD>noradrenalin</WSD> 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 reactions , additional tests seem to be desirable . 
Meaning of the word marked with <WSD> tags:  a catecholamine precursor of epinephrine that is secreted by the adrenal medulla and also released at synapses