the balance of opposing pre- and postsynaptic alpha 2-adrenoceptor effects will be important and this may require more dynamic tests than already mentioned , such as comparing the effect of alpha-methylnoradrenaline on plasma noradrenaline ( presynaptic effect ) and skin blood flow ( postsynaptic effect ) in the presence and absence of the partial alpha 2-agonist or antagonist under investigation .
C0025805
alpha-methylnoradrenaline
C0028351
noradrenaline