From Serotonin Receptor Classification to the Antimigraine Drug Sumatriptan

Cephalalgia ◽  
1992 ◽  
Vol 12 (4) ◽  
pp. 187-196 ◽  
Author(s):  
Pramod R Saxena ◽  
Michel D Ferrari
Keyword(s):  
Serotonin Receptors ◽  
Serotonin Receptor ◽  
Radioligand Binding ◽  
Receptor Subtype ◽  
Binding Studies ◽  
Rat Brain Membranes ◽  
Serotonin Derivatives ◽  
Parasympathetic Ganglion ◽  
Radioligand Binding Studies ◽  
New Framework

After the synthetic serotonin 5-hydroxytryptamine (5-HT) became available in the early 1950s, attempts were soon under way to study the nature of 5-HT receptors. Using the guinea-pig isolated ileum, Gaddum and Picarelli (1957) suggested that 5-HT-induced contractions were mediated by a morphine-sensitive “M” receptor located on the parasympathetic ganglion and a dibenzyline-sensitive “D” receptor located on the smooth muscle. Though this classification was used during the next three decades, it was realized that some effects of serotonin, for example vasoconstriction within the carotid vascular bed, were not mediated by either “M” or “D” receptors. When radioligand binding studies led to the identification of 5-HT1 and 5-HT2 “receptors” in the rat brain membranes, it became increasingly apparent that the two receptor classifications were not identical. Thus, a new framework for serotonin receptor nomenclature and classification was proposed: 5-HT 1 -like (5-HT 1), 5-HT 2 (formerly “D”) and 5-HT 3 (formerly “M”) receptors. At the present time, several subtypes of 5-HT 1 receptors as well as a 5-HT 4 receptor are also recognized. As the serotonin receptor classification was emerging to indicate that carotid vasoconstriction by serotonin is mediated by a subtype of 5-HT 1 receptors, on the migraine front it was being suggested that the disease is associated with vasodilatation within the cranial extracerebral circulation and deranged serotonin metabolism and that certain antimigraine drugs caused a selective carotid vasoconstriction, probably via serotonin receptors. Therefore, Humphrey and colleagues conceived that synthesis of serotonin derivatives may lead to a compound that would elicit highly selective carotid vasoconstriction and abort migraine attacks. Indeed, via the synthesis of 5-carboxamidotryptamine and AH25086, sumatriptan was designed. The drug acts as an agonist at the vasoconstrictor 5-HT 1 receptor subtype and has proved highly effective in the therapy of migraine attacks.

Cloning and functional expression of the hNPY Y5 receptor in human endometrial cancer (HEC-1B) cells

2000 ◽  
Vol 78 (2) ◽  
pp. 134-142 ◽  
Author(s):  
C Moser ◽  
G Bernhardt ◽  
J Michel ◽  
H Schwarz ◽  
A Buschauer
Keyword(s):  
Radioligand Binding ◽  
Functional Expression ◽  
Receptor Protein ◽  
Receptor Subtype ◽  
Functional Assay ◽  
Binding Studies ◽  
Binding Characteristics ◽  
Camp Synthesis ◽  
Camp Assay ◽  
Radioligand Binding Studies

Aiming to develop a functional assay for the human NPY Y5 receptor based on adenylyl cyclase activity, HEC-1B cells, in which cAMP synthesis can be efficiently stimulated with forskolin, were selected for the transfection with the pcDNA3-Y5-FLAG and the pcDEF3-Y5 vectors. After optimization of the transfection procedure, the binding of [3H]propionyl-NPY to transiently and stably expressed Y5 receptors was determined. The affinities of NPY, NPY derivatives, and rPP (pNPY >= p(Leu31Pro34)NPY = p(2-36)NPY >= p(D-Trp32)NPY > p(13-36)NPY > rPP) were in accordance with the NPY Y5 receptor subtype. For [3H]propionyl-pNPY approximately 1.7 × 105 and 1 × 106 binding sites per transiently and stably transfected cell, respectively, were determined. The KD values were 2.4 ± 0.4 and 1.7 ± 0.2 nM, respectively. Due to the high expression of the receptor protein, both stably and transiently transfected cells can be conveniently used in routine radioligand binding studies. By contrast, functional assays were only feasible with HEC-1B cells stably expressing the Y5 receptor. In these cells, 10 nM pNPY inhibited the forskolin-stimulated cAMP synthesis by 75%. This effect was partially antagonized by the Y5 antagonist N-{trans-[4-(2-naphthylmethylamino)- methyl]cyclohexylmethyl}naphthalene-2-sulfonamide. Although the genetic variability of cancer cells is in principle incompatible with a stable phenotype, both ligand binding characteristics and functionality of the Y5 receptor remained unchanged for more than 30 passages.Key words: human NPY Y5 receptor, HEC-1B cells, stable expression, radioligand binding, cAMP assay.

Bronchospasmolytic and Adenosine Binding Activity of 8- (Proline / Pyrazole)-Substituted Xanthine Derivatives

2020 ◽  
Vol 17 ◽  
Author(s):  
Sneha Singh ◽  
Madhwi Ojha ◽  
Divya Yadav ◽  
Sonja Kachler ◽  
Karl-Norbert Klotz ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Radioligand Binding ◽  
Binding Activity ◽  
Receptor Subtypes ◽  
Significant Protection ◽  
Binding Studies ◽  
Standard Drug ◽  
Xanthine Derivatives ◽  
Radioligand Binding Studies ◽  
Micromolar Range

Background: ABSTRACT: Background: 8-Phenyltheophylline derivatives exhibit prophylactic effects at a specific dose but do not produce the cardiovascular or emetic side effects associated with xanthines, thereby exhibiting unique characteristics of potential therapeutic importance. Methods: Novel series of 8-(proline/pyrazole)-substituted xanthine analogs has been synthesized. The affinity and selectivity of compounds to adenosine receptors have been assessed by radioligand binding studies. The synthesized compounds also showed good bronchospasmolytic properties (increased onset of bronchospasm; decreased duration of jerks) with 100% survival of animals in comparison to the standard drug. Besides, compound 8f & 9f showed good binding affinity in comparison to other synthesized compounds in the micromolar range. Results: The maximum binding affinity of these compounds was observed for A2B receptors, which is ~ 7 or 10 times higher as compared to A1, A2A and A3 receptors. The newly synthesized derivatives 8f, 9a-f, 17g-m, and 18g-m displayed significant protection against histamine aerosol induced bronchospasm in guinea pigs. Conclusion: Newly synthesized proline/pyrazole based xanthines compounds showed a satisfactory binding affinity for adenosine receptor subtypes. Replacement or variation of substituted proline ring with substituted pyrazole scaffold at 8thposition of xanthine moiety resulted in the reduction of adenosine binding affinity and bronchospasmolytic effects.

scholarly journals Living-Cell Diffracted X-ray Tracking Analysis Confirmed Internal Salt Bridge Is Critical for Ligand-Induced Twisting Motion of Serotonin Receptors

2021 ◽  
Vol 22 (10) ◽  
pp. 5285
Author(s):  
Kazuhiro Mio ◽  
Shoko Fujimura ◽  
Masaki Ishihara ◽  
Masahiro Kuramochi ◽  
Hiroshi Sekiguchi ◽  
...  
Keyword(s):  
Serotonin Receptors ◽  
Serotonin Receptor ◽  
Frame Rate ◽  
Receptor Subtype ◽  
Transmembrane Segment ◽  
Hek 293 ◽  
Gold Nanocrystals ◽  
X Ray ◽  
Time Dynamics ◽  
Analytical Technique

Serotonin receptors play important roles in neuronal excitation, emotion, platelet aggregation, and vasoconstriction. The serotonin receptor subtype 2A (5-HT2AR) is a Gq-coupled GPCR, which activate phospholipase C. Although the structures and functions of 5-HT2ARs have been well studied, little has been known about their real-time dynamics. In this study, we analyzed the intramolecular motion of the 5-HT2AR in living cells using the diffracted X-ray tracking (DXT) technique. The DXT is a very precise single-molecular analytical technique, which tracks diffraction spots from the gold nanocrystals labeled on the protein surface. Trajectory analysis provides insight into protein dynamics. The 5-HT2ARs were transiently expressed in HEK 293 cells, and the gold nanocrystals were attached to the N-terminal introduced FLAG-tag via anti-FLAG antibodies. The motions were recorded with a frame rate of 100 μs per frame. A lifetime filtering technique demonstrated that the unliganded receptors contain high mobility population with clockwise twisting. This rotation was, however, abolished by either a full agonist α-methylserotonin or an inverse agonist ketanserin. Mutation analysis revealed that the “ionic lock” between the DRY motif in the third transmembrane segment and a negatively charged residue of the sixth transmembrane segment is essential for the torsional motion at the N-terminus of the receptor.

Radioligand Binding Studies on the Nucleoside Transport Protein

1991 ◽  
pp. 411-414
Author(s):  
Ad P. Ijzerman ◽  
Armand Voorschuur ◽  
Marieke Kruidering ◽  
Irene M. Pirovano ◽  
Herman Van Belle ◽  
...  
Keyword(s):  
Radioligand Binding ◽  
Transport Protein ◽  
Nucleoside Transport ◽  
Binding Studies ◽  
Radioligand Binding Studies

Endothelium-independent vascular relaxation mediating ETB receptor in rabbit mesenteric arteries

1999 ◽  
Vol 276 (2) ◽  
pp. H383-H390 ◽  
Author(s):  
Takanori Iwasaki ◽  
Mitsuru Notoya ◽  
Yoko Hayasaki-Kajiwara ◽  
Toshitake Shimamura ◽  
Noriyuki Naya ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Radioligand Binding ◽  
Muscle Layer ◽  
Mesenteric Arteries ◽  
Binding Studies ◽  
Camp Content ◽  
Rabbit Mesenteric Artery ◽  
Etb Receptor ◽  
Radioligand Binding Studies ◽  
Rabbit Mesenteric Arteries

Vascular response mediating endothelin (ET)Breceptor was studied using isolated rabbit mesenteric arteries. ET-1 (0.1–30 nM) caused a concentration-dependent contraction, whereas ET-3 >100 nM caused only weak contraction. Up to 1 μM of sarafotoxin S6c showed no contraction. In arteries precontracted with phenylephrine, ET-3 (0.03–1 nM) caused a concentration-dependent relaxation, which was not affected by endothelium denudation. The ET-3-induced relaxation was antagonized by BQ-788 and PD-142893 but not by BQ-123 in the endothelium-denuded arteries. Treatment with indomethacin but not with N G-nitro-l-arginine methyl ester completely inhibited the relaxation. ET-3 stimulated the release of 6-keto-PGF1α and PGE2 from the endothelium-denuded arteries. ET-3 also significantly increased cAMP content but not cGMP content in the arteries. Radioligand-binding studies using serial sections of the artery revealed the expression of not only ETA but also ETB receptors in the smooth muscle layer of the arteries. These results suggest that ET-3 activates ETB receptor in smooth muscle cells of rabbit mesenteric artery, producing vasodilator prostaglandins from arachidonic acid probably via a catalysis of cyclooxygenase, which accumulates cAMP in subendothelial tissues and produces relaxations.

Synthesis and radioligand binding studies of bis-(8-isopropyl-isoquinolinium) derivatives as ligands for apamin-sensitive sites on cloned SK2 and SK3 channels

2011 ◽  
Vol 21 (22) ◽  
pp. 6756-6759 ◽  
Author(s):  
Eduard Badarau ◽  
Sébastien Dilly ◽  
Fabien Dufour ◽  
Sylvie Poncin ◽  
Vincent Seutin ◽  
...  
Keyword(s):  
Radioligand Binding ◽  
Binding Studies ◽  
Radioligand Binding Studies
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