scholarly journals Effect of 5-hydroxytryptamine Receptor in the Lower Esophageal Sphincter Regulation Mechanism

2020 ◽  
Vol 3 (6) ◽  
Author(s):  
Hefei Li ◽  
Junfeng Liu ◽  
Xixuan Zhang ◽  
Zhiwei Lai ◽  
Zhen Gao ◽  
...  
Keyword(s):  
G Protein ◽  
G Protein Coupled Receptors ◽  
Regulation Mechanism ◽  
Visceral Sensitivity ◽  
Gastrointestinal Dysfunction ◽  
Secretion Regulation ◽  
The Central Nervous System ◽  
Esophageal Sphincter ◽  
G Protein Coupled ◽  
The Brain

As a neurotransmitter and avascular active substance, the 5-hydroxytryptamine (5-HT, serotonin) is widely distributed in the central nervous system and surrounding tissues. The 5-HT can play its role by acting on its corresponding 5-HT receptor. Nowadays, the 5-HT receptor can be classified into seven, according to different signal transduction method of receptors, the 5-HT3 receptor belongs to the ligand-gated ion channels, while other six 5-HT receptors are involved into the G protein-coupled receptors and play the biological role by binding to specific G protein-coupled receptors (GPCRs) on the surface of the cell membrane. The 5-HT plays an important role in the brain-gut information transmission and studies showed that the physiological stimulations like having meals, and pathological stimulations like ischemia and stress could promote the release of the 5-HT. In the gastrointestinal tract, the 5-HT is closely related to gastrointestinal sensitivity, gastrointestinal movement and secretion regulation, as well as many gastrointestinal dysfunction disorders, such as gastrointestinal power and visceral sensitivity abnormality and abnormalities of brain-gut axis.

Complementary roles of mouse lipocalins in chemical communication and immunity

2014 ◽  
Vol 42 (4) ◽  
pp. 893-898 ◽  
Author(s):  
Romana Stopková ◽  
Barbora Dudková ◽  
Petra Hájková ◽  
Pavel Stopka
Keyword(s):  
Oral Cavity ◽  
G Protein ◽  
Primary Site ◽  
G Protein Coupled Receptors ◽  
Main Route ◽  
Evolutionary Forces ◽  
Biochemical Pathways ◽  
G Protein Coupled ◽  
The Brain ◽  
Exogenous Substances

A primary site of infection in mammals is the nostrils, representing the gate to the brain through olfactory and vomeronasal epithelia, eyes as a direct route to the brain via the optical nerve, and oral cavity representing the main route to the digestive tract. Similarly, pheromones, odorants and tastants enter animal bodies the same way. Therefore similar evolutionary forces might have shaped the evolution of systems for recognition of pathogens and chemical signals. This might have resulted in sharing various proteins among systems of recognition and filtering to decrease potential costs of evolving and utilizing unique biochemical pathways. This has been documented previously in, for example, multipurpose and widely distributed GPCRs (G-protein-coupled receptors). The aim of the present review is to explore potential functional overlaps or complementary functions of lipocalins in the system of perception of exogenous substances to reconstruct the evolutionary forces that might have shaped their synergistic functions.

Apelin/Apelin Receptor System: Molecular Characteristics, Physiological Roles, and Prospects as a Target for Disease Prevention and Pharmacotherapy

2020 ◽  
Vol 14 (2) ◽  
pp. 210-219
Author(s):  
Toshihiko Kinjo ◽  
Hiroshi Higashi ◽  
Kyosuke Uno ◽  
Nobuyuki Kuramoto
Keyword(s):  
G Protein ◽  
G Protein Coupled Receptors ◽  
Molecular Characteristics ◽  
Endogenous Ligand ◽  
Receptor System ◽  
Peripheral Tissues ◽  
The Central Nervous System ◽  
Apelin Receptor ◽  
Novel Target ◽  
G Protein Coupled

Background: Among the various orphan G protein-coupled receptors, apelin receptor (APJ), originally identified in the human genome as an orphan G-protein-coupled receptor, was deorphanised in 1998 with the discovery of its endogenous ligand, apelin. Apelin and APJ mRNA are widely expressed in peripheral tissues and the central nervous system in mammals. Objective: In this review, we discuss the characteristics, pharmacology, physiology, and pathology of the apelin/APJ system in mammals. Conclusion: Several physiological roles of the apelin/APJ system have been reported, including in homeostasis, cardiovascular maintenance, angiogenesis, and neuroprotection. In cellular signaling, apelin has been shown to drive the PI3K/Akt, MAPK, and PKA signaling pathways, leading to cell proliferation and protection from excitotoxicity. Apelin is also found in breast milk; therefore, apelin is believed to contribute to the establishment of the infant immune system. Furthermore, activation of the apelin/APJ system is reported to restore muscular weakness associated with aging. Thus, the apelin/APJ system represents a novel target for the prevention of several important cardiovascular and neurodegenerative diseases and the maintenance of health during old age.

scholarly journals A new family of orphan G protein-coupled receptors predominantly expressed in the brain 1

FEBS Letters ◽  
1998 ◽  
Vol 424 (3) ◽  
pp. 193-196 ◽  
Author(s):  
Olivier Valdenaire ◽  
Thomas Giller ◽  
Volker Breu ◽  
Ali Ardati ◽  
Anja Schweizer ◽  
...  
Keyword(s):  
G Protein ◽  
G Protein Coupled Receptors ◽  
New Family ◽  
G Protein Coupled ◽  
The Brain

Arrestin-dependent internalization of rhodopsin-like G protein-coupled receptors

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lizzy Wanka ◽  
Victoria Behr ◽  
Annette G. Beck-Sickinger
Keyword(s):  
G Protein ◽  
Receptor Activation ◽  
G Protein Coupled Receptors ◽  
Emotional Behavior ◽  
Model Systems ◽  
Regulation Mechanism ◽  
Interaction Sites ◽  
Internalization Process ◽  
G Protein Coupled ◽  
Receptor Family

Abstract The internalization of G protein-coupled receptors (GPCRs) is an important mechanism regulating the signal strength and limiting the opportunity of receptor activation. Based on the importance of GPCRs, the detailed knowledge about the regulation of signal transduction is crucial. Here, current knowledge about the agonist-induced, arrestin-dependent internalization process of rhodopsin-like GPCRs is reviewed. Arrestins are conserved molecules that act as key players within the internalization process of many GPCRs. Based on highly conserved structural characteristics within the rhodopsin-like GPCRs, the identification of arrestin interaction sites in model systems can be compared and used for the investigation of internalization processes of other receptors. The increasing understanding of this essential regulation mechanism of receptors can be used for drug development targeting rhodopsin-like GPCRs. Here, we focus on the neuropeptide Y receptor family, as these receptors transmit various physiological processes such as food intake, energy homeostasis, and regulation of emotional behavior, and are further involved in pathophysiological processes like cancer, obesity and mood disorders. Hence, this receptor family represents an interesting target for the development of novel therapeutics requiring the understanding of the regulatory mechanisms influencing receptor mediated signaling.

scholarly journals Development of novel potent ligands for GPR85, an orphan G protein-coupled receptor expressed in the brain

2021 ◽  
Author(s):  
Aya Sakai ◽  
Takeshi Yasui ◽  
Masashi Watanave ◽  
Rine Tatsumi ◽  
Yoshihiko Yamamoto ◽  
...  
Keyword(s):  
G Protein ◽  
G Protein Coupled Receptor ◽  
Orphan Receptors ◽  
Channel Opening ◽  
Ic50 Values ◽  
The Central Nervous System ◽  
Cerebellar Purkinje Cells ◽  
Electrophysiological Technique ◽  
G Protein Coupled ◽  
The Brain

GPR85 is a member of the G protein-coupled receptor and is a super-conserved receptor expressed in the brain sub-family (SREB) with GPR27 and GPR173. These three receptors are orphan receptors; however, their endogenous ligands have not been identified. SREB has garnered the interest of many scientists because it is expressed in the central nervous system and is evolutionarily conserved. In particular, brain mass is reported to be increased and learning and memory are improved in GPR85 knockout mice (Matsumoto et al., 2008). In this study, we characterized newly synthesized compounds using a GPR85-Gsα fusion protein and the [35S]GTPδS binding assay and identified novel GPR85 inverse-agonists with IC50 values of approximately 1 μM. To analyze the neurochemical character of the compounds and investigate the physiological significance of GPR85, we used cerebellar Purkinje cells expressing GPR85 and an electrophysiological technique. Based on the results, the inverse-agonist compound for GPR85 modulated potassium channel opening. Together with the results of previous gene analysis of GPR85, we expect that the development of the GPR85 ligand will provide new insights into a few types of neurological disorders.

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