A comparison of the actions of BIBN4096BS and CGRP(8-37) on CGRP and adrenomedullin receptors expressed on SK-N-MC, L6, Col 29 and Rat 2 cells.
1. The ability of the CGRP antagonist BIBN4096BS to antagonize CGRP and adrenomedullin has been investigated on cell lines endogenously expressing receptors of known composition. 2. On human SK-N-MC cells (expressing human calcitonin receptor-like receptor (CRLR) and receptor activity modifying protein 1 (RAMP1)), BIBN4096BS had a pA(2) of 9.95 although the slope of the Schild plot (1.37 +/- 0.16) was significantly greater than 1. 3. On rat L6 cells (expressing rat CRLR and RAMP1), BIBN4096BS had a pA(2) of 9.25 and a Schild slope of 0.89 +/- 0.05, significantly less than 1. 4. On human Colony (Col) 29 cells, CGRP(8-37) had a significantly lower pA(2) than on SK-N-MC cells (7.34 +/- 0.19 (n = 7) compared to 8.35 +/- 0.18, (n = 6)). BIBN4096BS had a pA(2) of 9.98 and a Schild plot slope of 0.86 +/- 0.19 that was not significantly different from 1. At concentrations in excess of 3 nM, it was less potent on Col 29 cells than on SK-N-MC cells. 5. On Rat 2 cells, expressing rat CRLR and RAMP2, BIBN4096BS was unable to antagonize adrenomedullin at concentrations up to 10 microM. CGRP(8-37) had a pA(2) of 6.72 against adrenomedullin. 6. BIBN4096BS shows selectivity for the human CRLR/RAMP1 combination compared to the rat counterpart. It can discriminate between the CRLR/RAMP1 receptor expressed on SK-N-MC cells and the CGRP-responsive receptor expressed by the Col 29 cells used in this study. Its slow kinetics may explain its apparent 'non-competitive' behaviour. At concentrations of up to 10 micro M, it has no antagonist actions at the adrenomedullin, CRLR/RAMP2 receptor, unlike CGRP(8-37).
Hay
Debbie L
DL
Pharmaceutical Sciences Research Institute, Aston University, Aston Triangle, Birmingham B4 7ET.
Howitt
Stephen G
SG
Conner
Alex C
AC
Doods
Henri
H
Schindler
Marcus
M
Poyner
David R
DR
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology*; D006801:Humans; D051379:Mice; D010446:Peptide Fragments / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology*; D011799:Quinazolines / Q000494:pharmacology*; D051381:Rats; D058265:Receptors, Adrenomedullin; D018015:Receptors, Calcitonin Gene-Related Peptide / Q000187:drug effects* / Q000378:metabolism; D018000:Receptors, Peptide / Q000037:antagonists & inhibitors / Q000187:drug effects* / Q000378:metabolism; D014407:Tumor Cells, Cultured
D010446:Peptide Fragments; D010879:Piperazines; D011799:Quinazolines; D058265:Receptors, Adrenomedullin; D018015:Receptors, Calcitonin Gene-Related Peptide; D018000:Receptors, Peptide; C058636:calcitonin gene-related peptide (8-37); D015740:Calcitonin Gene-Related Peptide; C406305:olcegepant