Drugs affecting noradrenergic

L Heureux R, Dennis T, Curet O, Scatton B. 1986. Measurement of endogenous noradrenaline release in the rat cerebral cortex in vivo by transcortical dialysis effects of drugs affecting noradrenergic transmission. J Neurochem 46(6) 1794-1801. 

One can simply classify a drug as noradrenergic on the basis of interaction with the transporter or specific receptor subtypes. But this does not really address the functional consequences, such as the extent to which, for instance, a drug affects the intrasynaptic concentration of norepinephrine. The latter requires some knowledge of the pathway followed by norepinephrine from synthesis, storage, release, and clearance. This pathway is depicted in Figure 15-1. 

The side-effect profile of venlafaxine is similar to that of SSRIs and includes gastrointestinal symptoms, sexual dysfunction, and transient discontinuation symptoms. Like the SSRIs, venlafaxine does not affect cardiac conduction or lower the seizure threshold. In most patients, venlafaxine is not associated with sedation or weight gain. Side effects that differ from those of SSRIs are hypothesized to be related to the increased noradrenergic activity of this drug at higher doses these side effects are dose-dependent anxiety (in some patients) and dose-dependent hypertension. 

ANTIDEPRESSANTS are used to relieve the symptoms of depressive illness, an affective disorder. There are three main groups of drugs used for the purpose. All interfere with the function of monoamine neurotransmitters, and the considerable delay before antidepressants become effective is taken as evidence of a down-regulation of noradrenergic or serotonergic systems (rather than the opposite, as advanced in Schildkraut s original amine theory of depression). 

Most studies support the view that clonidine and similar drugs exert their antihypertensive action by stimulating central medullary a-adreno-ceptors. Clonidine appears to act directly on the a-receptors since its action in rabbits is not affected by depleting central noradrenergic neurons with 6-hydroxydopamine. These receptors are probably of the pre-synaptic or a2-type and clonidine s actions are blocked by the selective... 

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