The Role of Adrenergic Receptors on Neural Excitability and Synaptic Plasticity: A Narrative Review

Adrenergic receptors have an important role in neural excitability and synaptic plasticity. Despite a lot of studies on these receptors, their exact role in brain disorders accompanied with hyperexcitability has not been determined. There are also controversies on their role in synaptic plasticity. In this review article, the important studies done in this regard have been reviewed to achieve a good summary of the effects of these receptors on neuronal excitability and synaptic plasticity. Despite the controversial results that have been reported in previous studies, it seems that alpha-1 and alpha-2 receptors decrease the neuronal excitability during seizure. Alpha 1A receptors, by acting on inhibitory interaneurons and increasing the GABAergic activity, are primarily responsible for the inhibitory function of alpha-1 receptors in reducing neuronal excitability, while beta-1 receptors may increase the excitability by increasing glutamate release. Moreover, alpha-1 receptor activity mostly induces long-term weakening in synapses. On the other hand, beta-adrenergic receptors increase the neuronal excitability and induce long-term potentiation through increasing both the glutamate release and the neurogenesis.