“… clonidine stimulate these presynaptic a2-receptors and … labelled noradrenaline during in vitro stimulation ( Galzin et al 1982) but also to a reduction in noradrenaline turnover in vivo, one manifestation of which is … (3-methoxy-4hydroxyphenyl-ethylene glycol sulphate), the major metabolite of noradrenaline in rat brain (Braestrup & Nielsen 1976).”