ABSTRACT
This chapter describes the effects of drugs upon the storage and release of noradrenaline. Three groups of agents are considered: drugs that modulate noradrenaline release by an action on prejunctional receptors of the postganglionic neurone terminal; drugs that impair sympathetic neurotransmission by depletion of transmitter; and, finally, the noradrenergic neurone blockers which interfere with noradrenaline release independently of prejunctional receptors. Prejunctional receptors are located at the axon terminal, and modulate transmitter release. Prejunctional receptors on sympathetic neurones may also be stimulated by transmitters from other adjacent neurones or by circulating or locally released autacoids. In this case they may be termed heteroreceptors. The evidence points to the receptor being of the same α2-subtype as found on the prejunctional site of sympathetic neurones. The destruction of sympathetic neurones is thought to involve an immune-mediated mechanism since it is associated with infiltration of lymphocytes into the ganglionic parenchyma.
