Signal transduction neuropeptides

Fig. 3 Mechanisms involved in the opioid ( r, 8, k, ORLi) and neuropeptide Y (Y2) receptor-mediated inhibition of exocytotic transmitter release. Following activation of the respective receptor and Gi/0 (1), three signal transduction pathways are possible, namely inhibition of voltage-dependent Ca2+ channels (2), opening of K+ channels (3), and a direct inhibitory effect on the vesicle release machinery (4). Glossary — > - leading to => - ion flux => - action potential Vm - membrane potential (+) and mean stimulatory and inhibitory effect, respectively.

A wide variety of ligands that use STM receptors and share signal transduction pathways will be considered and compared in this overview. This includes cell-derived chemokines, ETB4, PAF, complement-derived C5a, bacterial-derived fMFP, neuropeptides, and related ligands. 

The ion channel receptors are similar in structure to the nicotinic acetylcholine receptor (see Fig. 11.3). Signal transduction consists of the conformational change when ligand binds. Most small molecule neurotransmitters and some neuropeptides use ion channel receptors. 

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