**Isabella Salzer, Sutirtha Ray, Klaus Schicker and Stefan Boehm \***

Division of Neurophysiology and Neuropharmacology, Centre for Physiology and Pharmacology, Medical University of Vienna, Waehringerstrasse 13a, A-1090 Vienna, Austria; isabella.salzer@meduniwien.ac.at (I.S.); sutirtha.ray@meduniwien.ac.at (S.R.); klaus.schicker@meduniwien.ac.at (K.S.) **\*** Correspondence: stefan.boehm@meduniwien.ac.at; Tel.: +43-1-40160-31200

Received: 1 April 2019; Accepted: 13 May 2019; Published: 20 May 2019

**Abstract:** The prime task of nociceptors is the transformation of noxious stimuli into action potentials that are propagated along the neurites of nociceptive neurons from the periphery to the spinal cord. This function of nociceptors relies on the coordinated operation of a variety of ion channels. In this review, we summarize how members of nine different families of ion channels expressed in sensory neurons contribute to nociception. Furthermore, data on 35 different types of G protein coupled receptors are presented, activation of which controls the gating of the aforementioned ion channels. These receptors are not only targeted by more than 20 separate endogenous modulators, but can also be affected by pharmacotherapeutic agents. Thereby, this review provides information on how ion channel modulation via G protein coupled receptors in nociceptors can be exploited to provide improved analgesic therapy.

**Keywords:** nociceptor; inflammatory pain; G protein-coupled receptor; voltage-gated ion channel; TRP channel; K2*<sup>P</sup>* channel; Ca2<sup>+</sup>-activated Cl<sup>−</sup> channel
