Presynaptic receptors and modulation of neurotransmission: pharmacological implications and therapeutic relevance

During noradrenaline (NA) release elicited by the arrival of nerve impulses, the neurotransmitter interacts with specific receptors (α, β₁ or β₂-adrenoceptors) located in the membrane of the postsynaptic cell to trigger responses in the effector organ. Until a few years ago, the role o f noradrenergic nerve terminals in neurotransmission was considered to be concerned exclusively with the synthesis, storage, release, and inactivation of NA and there were no indications that receptors might also be present in the Presynaptic membrane. However, it is now clear that a number of Presynaptic receptors exist which modulate NA release. Here S. Z. Langer reviews their separate pharmacological properties and discusses the therapeutic relevance of these new findings.