Investigation of CGRP receptors and peptide pharmacology in human coronary arteries. Characterization with a nonpeptide antagonist.
Calcitonin gene-related peptide (CGRP), adrenomedullin (AM), and amylin are structurally related peptides mediating vasorelaxation in the coronary circulation possibly via CGRP receptors (subtypes 1 or 2). Functional CGRP1 receptors appear to consist of at least three different kinds of proteins: the calcitonin receptor-like receptor (CRLR), receptor-activity-modifying proteins (RAMPs) and the receptor component protein (RCP). No CGRP2 receptor has yet been cloned. Using reverse transcriptase - polymerase chain reaction, the presence of mRNA sequences encoding CRLR, RCP and RAMPs was demonstrated in human coronary arteries. Relaxant responses were studied on isolated segments of coronary arteries after precontraction with U46619 (9,11-dideoxy-11alpha,9alpha-epoxymethano-prostaglandin F(2alpha)). The human peptides alphaCGRP, AM, and amylin induced relaxation with mean pEC50 values of 8.6, 6.8, and 6.3 M, respectively. Preincubation with alphaCGRP(8-37) (10(-7) -10(-5) M) and a novel nonpeptide CGRP antagonist "Compound 1" (WO98/11128) (10(-7)-10(-5) M) caused a dose-dependent rightward shift of the concentration-response curves for alphaCGRP with pA(2) values of 7.0 and 7.1, respectively. Preincubation with alphaCGRP(8-37) (10(-6) M) and Compound 1 (10(-6) M) caused significant rightward shift of the concentration-response curves for AM and amylin as well with pK B values between 6.6 and 7.5. Preincubation with AM(22-52) had no antagonistic effect on the AM and amylin response, neither did diacetoamidomethyl cysteine CGRP cause any concentration dependent (10(-11)-10(-6) M) dilatation. In conclusion, mRNA for the components forming CGRP1 and AM receptors was detected in the human left anterior descending coronary arteries. alphaCGRP, AM, and amylin mediated vasorelaxation via the CGRP1 receptor. Compound 1 acted as a nonpeptide antagonist at the CGRP1 receptor and could thus become a tool for the study of CGRP-mediated functional responses in human tissue.
Hasbak
Philip
P
Department of Clinical Experimental Research, University Hospital of Copenhagen, Glostrup, Denmark. philip@post1.tele.dk
Saetrum Opgaard
Ole
O
Eskesen
Karen
K
Schifter
Søren
S
Arendrup
Henrik
H
Longmore
Jenny
J
Edvinsson
Lars
L
D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D053607:Adrenomedullin; D000328:Adult; D000682:Amyloid / Q000494:pharmacology; D015740:Calcitonin Gene-Related Peptide / Q000031:analogs & derivatives* / Q000494:pharmacology; D000077221:Calcitonin Gene-Related Peptide Receptor Antagonists; D058286:Calcitonin Receptor-Like Protein; D003331:Coronary Vessels / Q000187:drug effects*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D047908:Intracellular Signaling Peptides and Proteins; D058228:Islet Amyloid Polypeptide; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D010446:Peptide Fragments / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D058261:Receptor Activity-Modifying Proteins; D018003:Receptors, Calcitonin / Q000096:biosynthesis / Q000235:genetics; D018015:Receptors, Calcitonin Gene-Related Peptide / Q000187:drug effects*
C425984:4-(2-oxo-2,3-dihydrobenzimidazol-1-yl)piperidine-1-carboxylic acid (1-(3,5-dibromo-4-hydroxybenzyl)-2-oxo-2-(4-phenylpiperazin-1-yl)ethyl)amide; D000682:Amyloid; C545578:CALCRL protein, human; D000077221:Calcitonin Gene-Related Peptide Receptor Antagonists; D058286:Calcitonin Receptor-Like Protein; D047908:Intracellular Signaling Peptides and Proteins; D058228:Islet Amyloid Polypeptide; D008565:Membrane Proteins; D010446:Peptide Fragments; D010455:Peptides; D010879:Piperazines; D010880:Piperidines; D012333:RNA, Messenger; D058261:Receptor Activity-Modifying Proteins; D018003:Receptors, Calcitonin; D018015:Receptors, Calcitonin Gene-Related Peptide; C104782:adrenomedullin (22-52); C403775:calcitonin gene-related peptide, (acetylmethoxy)cysteinyl(2,7)-; C058636:calcitonin gene-related peptide (8-37); D053607:Adrenomedullin; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D015740:Calcitonin Gene-Related Peptide