this effect could not be attributed to a post-synaptic antagonism of tonically released endogenous noradrenaline , but may indicate a presynaptic action of clonidine , reducing noradrenaline release.5 these observations are thought to support the idea that clonidine may have an agonist action on noradrenaline receptors in the brain .
C0039869
thought
C0006104
brain