The ins and outs of adrenergic signaling.

Adrenergic signaling, in particular signaling in the sympathetic nervous system, is a prime example of the control of an essential physiological system. It has served as a model system both for the control of mediator release and for receptor signaling and regulation. This review covers the historical development of the field and then addresses issues that represent key fields of ongoing research: the mechanisms and kinetics of receptor activation, temporal patterns of downstream signaling and signal bias, receptor mobility and aggregation, and signal compartmentation and specificity. The available evidence suggests that adrenergic signaling may involve complex spatiotemporal patterns, which give texture to the signaling process and may contain additional biological information.