Quantitative autoradiography reveals higher densities of specific calcitonin-gene-related peptide receptors in small intramyocardial compared with large epicardial coronary arteries

1993 ◽  
Vol 84 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Bing Sun ◽  
Anthony P. Davenport ◽  
Morris J. Brown
Keyword(s):  
Coronary Artery ◽  
Coronary Arteries ◽  
Binding Sites ◽  
Specific Binding ◽  
Calcitonin Gene Related Peptide ◽  
Human Calcitonin ◽  
Related Peptide ◽  
Specific Binding Sites ◽  
Site Density ◽  
Calcitonin Gene

1. Binding sites for calcitonin-gene-related peptide were localized and characterized in porcine coronary arteries using quantitative autoradiography, and the density of binding sites was compared between large epicardial and small intramyocardial coronary arteries. 2. A single class of binding sites for calcitonin-gene-related peptide with a dissociation constant of 2.1 ± 0.2 nmol/l was detected in both the large and small coronary arteries. The density of specific binding sites was higher (maximum binding site density 231 ± 14 fmol/mg of protein) in the small coronary arteries than in the large epicardial coronary arteries (maximum binding site density 108 ± 5 fmol/mg of protein). β-Human calcitonin-gene-related peptide showed higher affinity than α-human calcitonin-gene-related peptide for the binding sites. Most of the specific binding sites for both peptides in the large coronary artery were localized in the intima and media. 3. In coronary artery from patients with coronary heart disease, there were more binding sites for calcitonin-gene-related peptide in the smooth muscle layer of atheromatous segments (7.2 ± 0.7 amol/mm2) than in that of normal segments (3.0 ± 0.3 amol/mm2, P < 0.002). 4. The present findings lend further support to the theory of regional variation in the vasodilator response to calcitonin-gene-related peptide in porcine coronary arteries, which seems to be due to different densities of a single type of receptor for calcitonin-gene-related peptide.

Comparative affinities of human adrenomedullin for 125I-labelled human alpha calcitonin gene related peptide ([125I)hCGRPα) and 125I-labelled Bolton – Hunter rat amylin ([125I]BHrAMY) specific binding sites in the rat brain

1995 ◽  
Vol 73 (7) ◽  
pp. 1084-1088 ◽  
Author(s):  
D. van Rossum ◽  
D. P. Ménard ◽  
R. Quirion ◽  
J. K. Chang
Keyword(s):  
Rat Brain ◽  
Binding Sites ◽  
Specific Binding ◽  
Biological Effects ◽  
Calcitonin Gene Related Peptide ◽  
Cross Reactivity ◽  
Related Peptide ◽  
Specific Binding Sites ◽  
Peptide Family ◽  
Calcitonin Gene

Adrenomedullin (ADM) is a recently identified peptide that shows some homology (~ 25%) with calcitonin gene related peptide (CGRP) and is now considered to be a new member of this peptide family. Because it shares biological effects with CGRP, we evaluated the possible affinity of human adrenomedullin (hADM) for 125I-labelled human CGRPα ([125I]hCGRPα) binding sites in the rat brain. Moreover, we evaluated the potential existence of cross-reactivity for 125I-labelled Bolton–Hunter rat amylin ([125I]BHrAMY), another member of this peptide family. In all brain areas investigated, hADM only competed with relatively low affinities for both [125I]hCGRPα and [125I]BHrAMY binding sites, with IC50 values generally in the high nanomolar – low micromolar range, the lowest affinity being observed for [125I]BHrAMY binding sites. Interestingly, the lowest affinities of hADM against both radioligands were detected in the nucleus accumbens and ventral striatum. These areas are known to be enriched with atypical CGRP – salmon calcitonin – amylin sensitive sites. It thus appears that hADM is unlikely to bind to this atypical site. Moreover, hADM demonstrated limited affinity for either [125I]hCGRPα or [125I]BHrAMY binding sites in the rat brain. This suggests that the potential biological effects of ADM in the brain could be mediated through a different class of receptors with higher affinity for this newly isolated peptide.Key words: adrenomedullin, calcitonin gene related peptide, amylin, rat brain.

scholarly journals Cross-reactivity of amylin with calcitonin-gene-related peptide binding sites in rat liver and skeletal muscle membranes

1991 ◽  
Vol 277 (1) ◽  
pp. 139-143 ◽  
Author(s):  
A Chantry ◽  
B Leighton ◽  
A J Day
Keyword(s):  
Skeletal Muscle ◽  
Binding Site ◽  
Rat Liver ◽  
Specific Binding ◽  
Calcitonin Gene Related Peptide ◽  
Cross Reactivity ◽  
Scatchard Analysis ◽  
Human Calcitonin ◽  
Related Peptide ◽  
Calcitonin Gene

This study examines whether the high degree of sequence identity between amylin and calcitonin-gene-related peptide (CGRP) is reflected in their cross-reactivity at the level of membrane receptor binding. Rat liver plasma membranes contain a specific saturable binding site for 125I-labelled human CGRP-1. Binding reached equilibrium within 30 min and was rapidly reversed by re-incubating membranes in the presence of 1 microM human CGRP. In addition, the presence of 50 mM- or 500 mM-NaCl lowered specific binding by 30% and 77% respectively. Scatchard analysis was consistent with a single high-affinity site with a dissociation constant (Kd) of 0.125 nM and binding capacity (Bmax.) of 580 fmol/mg of membrane protein. Specific binding of 125I-labelled human CGRP-1 to both liver and skeletal muscle membranes was inhibited by human CGRP-1 [IC50 (concn. causing half-maximal inhibition of binding) 0.1-0.3 nM], and rat amylin (IC50 10 nM), but not by human calcitonin. Covalent cross-linking of 125I-CGRP to its binding site in rat skeletal muscle and liver membranes resulted in labelling of a major species of about 70 kDa under reducing conditions and about 55 kDa under alkylating conditions, as visualized on SDS/PAGE. These radiolabelled species were absent in the presence of CGRP or amylin at 1 microM. These results are indicative of a common binding site for both CGRP and amylin in liver and skeletal muscle, and it is suggested that both peptides mediate their actions through the same effector system. The normal physiological importance and the relevance to the pathology of type 2 diabetes of these data are discussed.

Regional distribution and regulation of [125I]calcitonin gene-related peptide binding sites in coronary arteries

1992 ◽  
Vol 219 (3-4) ◽  
pp. 415-425 ◽  
Author(s):  
Gregory A. Knock ◽  
John Wharton ◽  
Jullien A.R. Gaer ◽  
Magdi H. Yacoub ◽  
Kenneth M. Taylor ◽  
...  
Keyword(s):  
Coronary Arteries ◽  
Binding Sites ◽  
Regional Distribution ◽  
Peptide Binding ◽  
Calcitonin Gene Related Peptide ◽  
Related Peptide ◽  
Calcitonin Gene

Calcitonin Gene-Related Peptide-Binding Sites of Porcine Cardiac Muscles and Coronary Arteries: Solubilization and Characterization

1989 ◽  
Vol 52 (6) ◽  
pp. 1919-1924 ◽  
Author(s):  
Yoshihisa Sano ◽  
Osamu Hiroshima ◽  
Teruaki Yuzuriha ◽  
Chiyuki Yamato ◽  
Akira Saito ◽  
...  
Keyword(s):  
Coronary Arteries ◽  
Binding Sites ◽  
Peptide Binding ◽  
Calcitonin Gene Related Peptide ◽  
Related Peptide ◽  
Calcitonin Gene ◽  
Cardiac Muscles

scholarly journals Calcitonin gene-related peptide receptor antagonist human CGRP-(8-37)

1989 ◽  
Vol 256 (2) ◽  
pp. E331-E335 ◽  
Author(s):  
T. Chiba ◽  
A. Yamaguchi ◽  
T. Yamatani ◽  
A. Nakamura ◽  
T. Morishita ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Adenylate Cyclase ◽  
Calcitonin Gene Related Peptide ◽  
Human Calcitonin ◽  
Liver Plasma Membrane ◽  
Related Peptide ◽  
Calcitonin Gene ◽  
Liver Membranes ◽  
Calcitonin Receptors ◽  
Stimulation Of

From this study, we predicted that the human calcitonin gene-related peptide (hCGRP) fragment hCGRP-(8-37) would be a selective antagonist for CGRP receptors but an agonist for calcitonin (CT) receptors. In rat liver plasma membrane, where CGRP receptors predominate and CT appears to act through these receptors, hCGRP-(8-37) dose dependently displaced 125I-[Tyr0]rat CGRP binding. However, hCGRP-(8-37) had no effect on adenylate cyclase activity in liver plasma membrane. Furthermore, hCGRP-(8-37) inhibited adenylate cyclase activation induced not only by hCGRP but also by hCT. On the other hand, in LLC-PK1 cells, where calcitonin receptors are abundant and CGRP appears to act via these receptors, the bindings of 125I-[Tyr0]rat CGRP and 125I-hCT were both inhibited by hCGRP-(8-37). In contrast to liver membranes, interaction of hCGRP-(8-37) with these receptors led to stimulation of adenosine 3',5'-cyclic monophosphate (cAMP) production in LLC-PK1 cells, and moreover, this fragment did not inhibit the increased production of cAMP induced not only by hCT but also by hCGRP. Thus hCGRP-(8-37) appears to be a useful tool for determining whether the action of CGRP as well as that of CT is mediated via specific CGRP receptors or CT receptors.

Sign in / Sign up

Export Citation Format

Share Document