scholarly journals Co-Evolution of Opioid and Adrenergic Ligands and Receptors: Shared, Complementary Modules Explain Evolution of Functional Interactions and Suggest Novel Engineering Possibilities

Life ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1217
Author(s):  
Robert Root-Bernstein ◽  
Beth Churchill

Cross-talk between opioid and adrenergic receptors is well-characterized and involves second messenger systems, the formation of receptor heterodimers, and the presence of extracellular allosteric binding regions for the complementary ligand; however, the evolutionary origins of these interactions have not been investigated. We propose that opioid and adrenergic ligands and receptors co-evolved from a common set of modular precursors so that they share binding functions. We demonstrate the plausibility of this hypothesis through a review of experimental evidence for molecularly complementary modules and report unexpected homologies between the two receptor types. Briefly, opioids form homodimers also bind adrenergic compounds; opioids bind to conserved extracellular regions of adrenergic receptors while adrenergic compounds bind to conserved extracellular regions of opioid receptors; opioid-like modules appear in both sets of receptors within key ligand-binding regions. Transmembrane regions associated with homodimerization of each class of receptors are also highly conserved across receptor types and implicated in heterodimerization. This conservation of multiple functional modules suggests opioid–adrenergic ligand and receptor co-evolution and provides mechanisms for explaining the evolution of their crosstalk. These modules also suggest the structure of a primordial receptor, providing clues for engineering receptor functions.

Author(s):  
Peggy Mason

Ionotropic and metabotropic receptors differ in their speed of action, the variety of effects produced after ligand-binding, and in the number of types present in the nervous system. The participation of two ionotropic glutamate receptors in synaptic plasticity is thought to be the cellular basis of learning. The actions of acetylcholine on nicotinic acetylcholine receptors present at the neuromuscular junction are described. The pharmacological profile of the GABAA receptor, central to most neural functions, is introduced. The properties of metabotropic receptors that are coupled to G proteins, termed G protein-coupled receptors (GPCRs), are detailed. Three canonical second-messenger systems through which GPCRs act are briefly described. An introduction to clinical pharmacology focused on how drugs acting on muscarinic and adrenergic receptors produce peripheral and central psychotropic effects is provided. Finally, the role of connexins and gap junctions in myelination and hearing is introduced.


2010 ◽  
Vol 12 (11) ◽  
pp. 2873-2884 ◽  
Author(s):  
Jesús Lacal ◽  
Cristina García-Fontana ◽  
Francisco Muñoz-Martínez ◽  
Juan-Luis Ramos ◽  
Tino Krell

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