QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Data Supplement All Versions of this Article: jpet.107.130344v1 324/2/416    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Salvatore, C. A. Articles by Kane, S. A. Search for Related Content PubMed PubMed Citation Articles by Salvatore, C. A. Articles by Kane, S. A.

NEUROPHARMACOLOGY

Pharmacological Characterization of MK-0974 [N-[(3R,6S)-6-(2,3-Difluorophenyl)-2-oxo-1-(2,2,2-trifluoroethyl)azepan-3-yl]-4-(2-oxo-2,3-dihydro-1H-imidazo[4,5-b]pyridin-1-yl)piperidine-1-carboxamide], a Potent and Orally Active Calcitonin Gene-Related Peptide Receptor Antagonist for the Treatment of Migraine

Departments of Pain Research (C.A.S., E.L.M., S.A.K.), Molecular Endocrinology (J.C.H., H.A.C.), Medicinal Chemistry (J.F.F., S.D.M., C.S.B., D.V.P., A.W.S., S.L.G., J.P.V., T.M.W.), and Worldwide Product Safety & Epidemiology (V.K.J.), Merck Research Laboratories, West Point, Pennsylvania; and Basic Research Administration (K.S.K.), Merck Research Laboratories, Rahway, New Jersey

Received August 16, 2007; accepted November 21, 2007.

	Abstract

Top Abstract Materials and Methods Results Discussion References

 
Calcitonin gene-related peptide (CGRP) is a potent neuropeptide that plays a key role in the pathophysiology of migraine headache. CGRP levels in the cranial circulation are increased during a migraine attack, and CGRP itself has been shown to trigger migraine-like headache. The correlation between CGRP release and migraine headache points to the potential utility of CGRP receptor antagonists as novel therapeutics in the treatment of migraine. Indeed, clinical proof-of-concept in the acute treatment of migraine was demonstrated with an intravenous formulation of the CGRP receptor antagonist BIBN4096BS (olcegepant). Here we report on the pharmacological characterization of the first orally bioavailable CGRP receptor antagonist in clinical development, MK-0974 [N-[(3R,6S)-6-(2,3-difluorophenyl)-2-oxo-1-(2,2,2-trifluoroethyl)azepan-3-yl]-4-(2-oxo-2,3-dihydro-1H-imidazo[4,5-b]pyridin-1-yl)piperidine-1-carboxamide]. In vitro, MK-0974 is a potent antagonist of the human (K_i = 0.77 nM) and rhesus (K_i = 1.2 nM) CGRP receptors but displays >1500-fold lower affinity for the canine and rat receptors as determined via ¹²⁵I-human CGRP competition binding assays. A rhesus pharmacodynamic assay measuring capsaicin-induced changes in forearm dermal blood flow via laser Doppler imaging was utilized to determine the in vivo activity of CGRP receptor antagonism. MK-0974 produced a concentration-dependent inhibition of dermal vasodilation, generated by capsaicin-induced release of endogenous CGRP, with plasma concentrations of 127 and 994 nM required to block 50 and 90% of the blood flow increase, respectively. In conclusion, MK-0974 is a highly potent, selective, and orally bioavailable CGRP receptor antagonist, which may be valuable in the acute treatment of migraine.

Although a complete understanding of the pathogenesis of migraine is not clear, several lines of evidence in migraineurs support a role of CGRP as a key mediator in the pathophysiology of migraine. CGRP levels in the cranial circulation are increased during a migraine attack (Goadsby et al., 1990), and intravenous administration of CGRP to migraineurs induced a delayed migrainous headache in some patients (Lassen et al., 1998). Nitroglycerine-induced migraine, which is clinically very similar to spontaneous attacks, is also characterized by increased levels of CGRP in plasma (Juhasz et al., 2003). Furthermore, successful treatment of migraine headache pain with the 5-hydroxytryptamine_1B/1D agonist sumatriptan resulted in the normalization of CGRP levels (Goadsby and Edvinsson, 1993). Finally, compelling evidence for a role of CGRP in migraine was obtained with the demonstration that intravenous administration of the potent CGRP receptor antagonist olcegepant (BIBN4096BS) was effective in the acute treatment of migraine (Olesen et al., 2004).

CGRP is widely distributed in the central and peripheral nervous system (van Rossum et al., 1997) where it is found within C and A nerve fibers (Hargreaves, 2007). Current hypotheses indicate that migraine is a neurological disorder and that the brainstem is pivotal to the pathophysiology. It has recently been shown that application of CGRP caused an increase in dural blood flow in rats but did not cause sensitization of meningeal nociceptors (Levy et al., 2005). Additionally, intravenous administration of the CGRP receptor antagonist BIBN4096BS reduced spontaneous and thermally evoked activity in the spinal trigeminal nucleus of rats (Fischer et al., 2005) and inhibited trigeminocervical superior sagittal sinus-evoked activity in the cat (Storer et al., 2004). Taken together this information lends support to the hypothesis that a site of action of CGRP in the pathogenesis of migraine may reside within the brainstem.

The overwhelming body of evidence supporting the involvement of CGRP in the pathogenesis of migraine led us to undertake a research program aimed at identifying orally bioavailable CGRP receptor antagonists that would be suitable for the treatment of migraine. Such compounds would provide a new option for migraine treatment with the potential for a differentiated profile relative to the standard of care, the 5-hydroxytryptamine_1B/1D receptor agonists, which form the triptan class of antimigraine drugs. Whereas triptans are adequately safe when used appropriately (Dodick et al., 2004), these compounds are contraindicated for patients with cardiovascular disease because they are potent vasoconstrictors (Goadsby et al., 2002). A CGRP receptor antagonist is expected to be devoid of direct vasoconstrictor activity (Doods, 2001; Edvinsson, 2003; Petersen et al., 2003) and would be a significant advance in the current standard of migraine care.

We have previously described the identification of a novel benzodiazepine CGRP receptor antagonist by high-throughput screening (Williams et al., 2006). Subsequent lead optimization led to the identification of the potent and orally bioavailable CGRP receptor antagonist MK-0974 (Paone et al., 2007). MK-0974 displayed good oral bioavailability in rats (20%) and dogs (35%). In rats, clearance was low (9.4 ml/min/kg) with a moderate i.v. half-life (1.6 h) and a short oral T_max (0.67 h). In dogs, clearance was moderate at 17 ml/min/kg. Recent clinical results from a Phase 2 study showed that MK-0974 significantly improved migraine pain relief 2 h after dosing compared to placebo, and the relief was sustained throughout 24 h (Ho et al., 2007). The present study examines the in vitro and in vivo pharmacological profile of MK-0974.

	Materials and Methods

Top Abstract Materials and Methods Results Discussion References

 
Expression Vector Constructs. Human cDNA for CLR was provided by Dr. Douglas MacNeil (Merck Research Laboratories, Rahway, NJ) and subcloned as a NheI-PmeI fragment into pIREShyg2 (Clontech, Mountain View, CA), which had been digested with NheI and EcoRV. Human RAMP1, RAMP2, and RAMP3 cDNAs were provided by Dr. Bruce Dougherty (Merck Research Laboratories, Rahway, NJ) and subcloned as NheI-NotI fragments into pIRE-Spuro2 (Clontech, Mountain View, CA).

Cell Culture and Generation of Recombinant Cell Lines. HEK293 cells were cultured in Dulbecco's modified Eagle's medium with 4.5 g/l glucose, 1 mM sodium pyruvate, and 2 mM glutamine supplemented with 10% fetal bovine serum, 100 units/ml penicillin, and 100 µg/ml streptomycin and maintained at 37°C, 5% CO₂, and 95% humidity. Cells were subcultured by treatment with 0.25% trypsin with 0.1% EDTA in Hanks' balanced salt solution.

For stable transfections 24 h before transfection cells were seeded at 3 x 10⁶/T75 flask. Transfections were performed by combining 5 µg of human CLR and 5 µg of human RAMP with 30 µg of Lipofectamine 2000 (Invitrogen, Carlsbad, CA). The transfection cocktail was added directly to the medium. Twenty-four hours later, the cells were passaged into fresh medium, and growth medium plus 300 µg/ml hygromycin and 1.0 µg/ml puromycin was added the following day. Clonal cell populations were generated via single cell sorting and maintained in growth medium containing 150 µg/ml hygromycin and 0.5 µg/ml puromycin.

Membrane Preparation and Radioligand Binding Studies. Stably transfected HEK293 cells were washed once with PBS and harvested in harvest buffer containing 50 mM HEPES, 1 mM EDTA, and Complete protease inhibitors (Roche Diagnostics, Indianapolis, IN). The cell suspension was disrupted with a laboratory homogenizer and centrifuged at 48,000g to isolate membranes. The pellets were resuspended in harvest buffer plus 250 mM sucrose. Membranes were stored at –70°C as aliquots. Membranes from rat and dog brains were prepared similarly. SK-N-MC membranes were purchased from Receptor Biology, Inc. (Beltsville, MD). Rhesus cerebellum was disrupted using a laboratory homogenizer in 10 mM HEPES and 5 mM MgCl₂ and used directly in binding experiments.

Competition binding assays were conducted by combining antagonist and 500 nM Compound 3 (Hershey et al., 2005) or 100 nM unlabeled CGRP for nonspecific binding, 10 pM ¹²⁵I-hCGRP (GE Healthcare, Piscataway, NJ), followed by 10 µg of CLR/RAMP1, 25 µg of SK-N-MC, 100 µg of brain, or 1 mg of rhesus cerebellum membranes and incubated for 3 h at room temperature in binding buffer (10 mM HEPES, 5 mM MgCl₂, and 0.2% bovine serum albumin) in a total volume of 1 ml. Adrenomedullin binding assays were set up as above but with 7.5 µg of CLR/RAMP2 or 5 µg of CLR/RAMP3 membranes, 10 pM ¹²⁵I-human adrenomedullin (GE Healthcare) as the radioligand, and 10 nM unlabeled human adrenomedullin for nonspecific binding. Incubations were terminated by filtration through GF/B 96-well filter plates that had been blocked with 0.5% polyethylenimine. Data were analyzed using GraphPad Prism (GraphPad Software, Inc., San Diego, CA), and the K_i was determined using the equation K_i = IC₅₀/1 + ([ligand]/K_d). The K_d values for the CGRP and adrenomedullin receptors were determined by saturation binding experiments (data not shown).

Functional Studies. HEK293 cells stably transfected with CLR/RAMP1 were plated in complete growth medium at 85,000 cells/well in 96-well poly-D-lysine-coated plates and cultured for 19 h before assay. Cells were washed with PBS and then incubated with inhibitor in the presence or absence of 50% human serum (SeraCare, Inc., Oceanside, CA) for 30 min at 37°C and 95% humidity in Cellgro Complete Serum-Free/Low-Protein medium (Mediatech, Inc., Herndon, VA) with L-glutamine and 1 g/l bovine serum albumin. Isobutylmethylxanthine was added to the cells at a concentration of 300 µM and incubated for 30 min at 37°C. Human -CGRP was added to the cells at a concentration of 0.3 nM and allowed to incubate at 37°C for 5 min. After -CGRP stimulation, the cells were washed with PBS and processed for cAMP determination using the two-stage assay procedure according to the manufacturer's recommended protocol (cAMP SPA direct screening assay system; RPA 559; GE Healthcare). Dose-response curves were plotted, and IC₅₀ values were determined. Schild analysis was used as a measure of competitive antagonism by plotting log (DR-1) versus log [B], where DR is the ratio of the EC₅₀ values in the presence and absence antagonist and [B] is the antagonist concentration. The X-intercept is equal to the pA₂, and the K_B was calculated using the formula pA₂ = –log K_B.

Rhesus Pharmacodynamic Assay. All procedures related to the use of animals were approved by the Institutional Animal Care and Use Committee at Merck Research Laboratories (West Point, PA) and conform with the Guide for the Care and Use of Laboratory Animals (Institute of Laboratory Animal Resources, 1996). Rhesus monkeys (male and female) weighing between 4 and 10 kg were anesthetized initially with ketamine (0.1 ml/kg i.m.) and then placed in the supine position on a temperature-controlled water circulating blanket and intubated with a 3-mm tracheal tube connected to 1-liter oxygen/1 to 2% isoflurane gas anesthesia. The right saphenous vein was cannulated for intravenous drug delivery, and blood samples were obtained from the left saphenous artery. Four rubber O-rings (8 mm inner diameter) were placed on the ventral side of the forearm without directly being positioned over a visible vessel.

A laser Doppler imager (Moor Instruments, Ltd., Millwey, Axminster, Devon, UK) was used to generate a color-coded image of dermal blood flow and quantitate the vasodilatory response to topically applied capsaicin. Using the manufacturer supplied software, average blood flow, expressed as perfusion units, was determined within the specified region of interest. After a baseline scan, a capsaicin solution (2 mg in 30% ethanol/20% Tween 20) was added inside one of the rings to obtain a control response. The O-rings served both as a well to contain the topically applied solution and also standardized the region of interest during data analysis. The capsaicin-induced changes in dermal blood flow were monitored by obtaining laser Doppler scans at 5, 10, and 20 min post-capsaicin. After obtaining the control capsaicin response, MK-0974 was administered intravenously using a dose-escalating protocol, including a bolus dose delivered in a volume of 500 µl (0.03 to 3.7 mg/kg i.v.) followed by a 25-min continuous infusion (0.13 to 20 µg/kg/min i.v.) at a rate of 0.025 ml/min to target plasma concentrations ranging from 31 nM to 5 µM. Five minutes after the start of each infusion, capsaicin was applied to an unused ring, and the vasodilatory response was measured after 5, 10, and 20 min. The blood flow response at 20 min post-capsaicin was compared to the control response (i.e., before administration of antagonist) to determine the percentage inhibition. Plasma samples were obtained at the 20-min time point to correlate the pharmacodynamic effect to the plasma concentration of MK-0974.

	Results

Top Abstract Materials and Methods Results Discussion References

 
Binding Studies on CGRP Receptors. Competitive binding experiments were carried out to determine the relative affinity of MK-0974 (Fig. 1) for human, rhesus, rat, and dog CGRP receptors. MK-0974 displayed high affinity for the native human CGRP receptor in SK-N-MC cells and for the recombinant human receptor, as measured by the ability to compete with ¹²⁵I-hCGRP binding with K_i values of 0.78 ± 0.05 (n = 10) and 0.77 ± 0.07 nM (n = 13), respectively. MK-0974 displayed a similar affinity (K_i) for the rhesus receptor (1.2 ± 0.08 nM; n = 10) as that for human, but it displayed >1500-fold lower affinity for the canine and rat receptors, with values of 1204 ± 38 (n = 10) and 1192 ± 56 nM (n = 10), respectively (Fig. 2).

View larger version (12K): [in this window] [in a new window]   Fig. 1. Chemical structure of MK-0974.

View larger version (21K): [in this window] [in a new window]   Fig. 2. Concentration-dependent inhibition of 125I-hCGRP binding by MK-0974 from SK-N-MC, CLR/RAMP1, rhesus cerebellum, dog brain, and rat brain membranes. Mean values ± S.E.M.

Binding Studies on Human Adrenomedullin Receptors. Competitive binding experiments were carried out to determine the selectivity of MK-0974 for the human CGRP receptor versus the related human adrenomedullin receptors. MK-0974 displayed little to no affinity for the human adrenomedullin receptors as measured by the ability to compete with ¹²⁵I-human adrenomedullin, with K_i values of >100 and 29 µM on CLR/RAMP2 and CLR/RAMP3, respectively.

Functional Studies on the Human CGRP Receptor. The effect of MK-0974 on CGRP-induced cAMP production in CLR/RAMP1 cells was investigated. Consistent with the binding data, MK-0974 potently blocked human -CGRP-stimulated cAMP responses in human CGRP receptor expressing HEK293 cells with an IC₅₀ of 2.2 ± 0.29 nM (n = 8). The addition of 50% human serum (IC₅₀ = 10.9 ± 2.1 nM; n = 10) reduced the apparent potency of MK-0974 by approximately 5-fold.

Increasing concentrations of MK-0974 caused a dose-dependent rightward shift in the CGRP dose-response curve, with no reduction in the maximal agonist response (Fig. 3A). Schild regression (Fig. 3B) yielded a pA₂ value of 8.9 (n = 4; K_B = 1.1 nM).

View larger version (15K): [in this window] [in a new window]   Fig. 3. Concentration-response curve and Schild plot analysis of MK-0974. A, concentration response curves of CGRP-induced cAMP production in HEK293 cells stably expressing human CLR/RAMP1 in the absence or presence of increasing concentrations of MK-0974 (n = 4). B, Schild plot showing the effect of MK-0974 on cAMP production in HEK293 cells stably expressing human CLR/RAMP1.

Effect of MK-0974 on Capsaicin-Induced Vasodilation in Rhesus. The increase in dermal vasodilation in response to capsaicin was found to be concentration- and time-dependent. A dose of 2 mg of capsaicin caused a 30% increase in dermal blood flow 20 min postapplication. Infusion of increasing doses of MK-0974 resulted in the blockade of the capsaicin-induced vasodilation response, illustrated in Fig. 4, affording EC₅₀ and EC₉₀ values of 127 nM or 71.9 ng/ml (95% confidence interval from 56 to 257 nM) and 994 nM or 563 ng/ml (95% confidence interval from 643 to 1600 nM), respectively (Fig. 5A). Further pharmacodynamic studies with MK-0974 (i.v. bolus, 1 mg/kg) demonstrated that the efficacy of this antagonist was time-dependent and correlated with plasma levels (Fig. 5B).

View larger version (26K): [in this window] [in a new window]   Fig. 4. Laser Doppler images of dermal blood flow in the rhesus forearm in response to topical application of capsaicin before and after administration of MK-0974. Dermal blood flow during baseline (A) and 20 min following topical application of capsaicin (B), which produced a 47% increase in blood flow within the highlighted O-ring. After obtaining the control response to capsaicin, MK-0974 was administered intravenously (0.91 mg/kg i.v. bolus, followed by 4.9 µg/kg/min i.v. infusion) and dermal blood flow measured in the highlighted O-ring before (C) and 20 min (D) after capsaicin application. There was only a 3% increase in capsaicin-induced dermal blood flow (D) in the presence of MK-0974 (973 nM plasma).

View larger version (17K): [in this window] [in a new window]   Fig. 5. Effects of MK-0974 on capsaicin-induced dermal vasodilation in rhesus monkey. A, MK-0974 dose-dependently inhibits capsaicin-induced dermal vasodilation in the rhesus forearm. Bar graph depicts the data from several experiments (n = 2–6 per target exposure) in which various plasma concentrations were targeted, actual plasma concentration was measured, and the percentage inhibition of capsaicin-induced vasodilation was determined. The calculated EC50 = 127 nM (95% confidence interval from 56 to 257 nM) and EC90 = 994 nM (95% confidence interval from 643 to 1600 nM). B, MK-0974 inhibits capsaicin-induced dermal vasodilation in a time-dependent manner and correlates with plasma levels. Data represent mean ± S.E.M. (n = 5 animals tested one to two times each).

	Discussion

Top Abstract Materials and Methods Results Discussion References

 
In this report, we detail the pharmacological profile of MK-0974, a structurally novel CGRP receptor antagonist in clinical development for the acute treatment of migraine. Furthermore, a rhesus dermal vasodilation assay, which relies on the CGRP-mediated response to topically applied capsaicin as a pharmacodynamic measure, was employed to assess the in vivo potency of MK-0974. The affinity of MK-0974 for the human CGRP receptor was established for both the recombinant and native receptors. To confirm that the recombinant CGRP receptor stably expressed in HEK293 cells exhibited physiologically relevant pharmacology, comparisons were made to the native human receptor found in SK-N-MC cells (Semark et al., 1992). MK-0974 displayed equal affinity for the native and cloned receptor as determined by radioligand binding experiments. MK-0974 functioned as a competitive antagonist of CGRP-induced cAMP accumulation in cells expressing the recombinant human CGRP receptor.

MK-0974 was highly selective for the CGRP receptor versus the closely related human adrenomedullin receptors, CLR/RAMP2 and CLR/RAMP3, and displayed no significant activity (IC₅₀ > 10 µM) in a screen of 166 enzyme and binding assays, including the human calcitonin receptor (MDS Pharma Services, Taipei, Taiwan; partial list of assays summarized in supplemental data).

It is well documented that small-molecule antagonists of the CGRP receptor exhibit species-selective pharmacology (Doods et al., 2000; Edvinsson et al., 2001; Hasbak et al., 2001; Mallee et al., 2002), and MK-0974 is no exception. MK-0974 displayed marked species-selectivity, exhibiting approximately 1500-fold higher affinity for the human and rhesus CGRP receptors compared to the rat and dog CGRP receptors. We have previously demonstrated that RAMP1 is responsible for the high-affinity binding of the BIBN4096BS class of antagonist (Mallee et al., 2002) via in vitro transient mixed species cotransfections of CLR and RAMP1. MK-0974 was evaluated in a similar manner, and it was determined that RAMP1 governs species selectivity of MK-0974 (data not shown).

The pronounced species-selectivity exhibited by MK-0974 required the utilization of nonhuman primate to assess in vivo pharmacological activity. Thus, pharmacological studies were conducted in rhesus monkey utilizing a capsaicin-induced dermal vasodilation assay (Hershey et al., 2005). Topical application of capsaicin to the rhesus forearm resulted in an increase in dermal blood flow directly measurable via laser Doppler imaging. The increased blood flow in response to the topical application of capsaicin is a direct result of endogenous CGRP release via activation of TRPV1 receptors (Akerman et al., 2003), and the ability of a CGRP receptor antagonist to block capsaicin-induced vasodilation provides pharmacodynamic evidence of in vivo receptor blockade. MK-0974 produced a concentration-dependent inhibition of capsaicin-induced dermal vasodilation in the rhesus forearm. Furthermore, a pharmacokinetic-pharmacodynamic relationship was observed between plasma concentrations of MK-0974 and inhibition of dermal vasodilation, suggesting a predictable pharmacokinetic/pharmacodynamic relationship. The plasma concentration of MK-0974 required to block rhesus dermal vasodilation is higher than anticipated when based solely upon the intrinsic affinity (rhesus K_i = 1.2 nM) of the molecule. When evaluated in the human in vitro functional assay, MK-0974 exhibited a 5-fold reduction in potency in the presence of serum (IC₅₀ = 2.2 and 10.9 nM in the absence and presence of serum, respectively), suggesting a significant degree of associative plasma protein binding. Taking into account the loss in potency in the presence of serum, there is only a 10-fold difference between the human serum-shifted in vitro IC₅₀ and the rhesus in vivo EC₅₀. MK-0974 displayed approximately the same affinity for the rhesus and human receptors; therefore, comparing the human IC₅₀ to the rhesus in vivo EC₅₀ is probably a valid comparison. Additionally, one cannot rule out the potential of a central nervous system mechanism playing a role in the capsaicin response via dorsal root reflexes (Lin et al., 1999). In summary, the rhesus model is nonterminal, noninvasive, rapid, and quantitative, making it an ideal pharmacodynamic model. It is noteworthy that this model was translated to the clinical setting and served as a valuable tool for dose selection for the clinical development of MK-0974 (Sinclair et al., 2007).

In conclusion, we have identified a potent, highly selective, and orally bioavailable small molecule CGRP receptor antagonist. CGRP receptor antagonists offer a novel mechanism of action for the management of migraine. Phase 3 clinical studies are ongoing with MK-0974 to better understand the potential promise of this class of molecules.

	Footnotes

 
Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.

doi:10.1124/jpet.107.130344.

ABBREVIATIONS: CGRP, calcitonin gene-related peptide; CLR, calcitonin receptor-like receptor; hCGRP, human CGRP; MK-0974, N-[(3R,6S)-6-(2,3-difluorophenyl)-2-oxo-1-(2,2,2-trifluoroethyl)azepan-3-yl]-4-(2-oxo-2,3-dihydro-1H-imidazo[4,5-b]pyridin-1-yl)piperidine-1-carboxamide; RAMP, receptor activity-modifying protein; BIBN4096BS, olcegepant; HEK, human embryonic kidney; PBS, phosphate-buffered saline; TRPV1, transient receptor potential vanilloid subfamily member 1.

The online version of this article (available at http://jpet.aspetjournals.org) contains supplemental material.

Address correspondence to: Dr. Christopher A. Salvatore, Merck Research Laboratories, WP26A-2000, West Point, PA 19486. E-mail: christopher_salvatore{at}merck.com

	References

Top Abstract Materials and Methods Results Discussion References

 

Akerman S, Kaube H, and Goadsby PJ (2003) Vanilloid type 1 receptors (VR1) on trigeminal sensory nerve fibres play a minor role in neurogenic dural vasodilatation, and are involved in capsaicin-induced dural dilation. Br J Pharmacol 140: 718–724.[CrossRef][Medline]

Amara SG, Jonas V, Rosenfeld MG, Ong ES, and Evans RM (1982) Alternative RNA processing in calcitonin gene expression generates mRNAs encoding different polypeptide products. Nature 298: 240–244.[CrossRef][Medline]

Dodick D, Lipton RB, Martin V, Papademetriou V, Rosamond W, VanDenBrink AM, Loutfi H, Welch KM, Goadsby PJ, Hahn S, et al. (2004) Consensus statement: cardiovascular safety profile of triptans (5-HT_1B/1D agonists) in the acute treatment of migraine. Headache 44: 414–425.[CrossRef][Medline]

Doods H (2001) Development of CGRP antagonists for the treatment of migraine. Curr Opin Investig Drugs 2: 1261–1268.[Medline]

Doods H, Hallermayer G, Wu D, Entzeroth M, Rudolf K, Engel W, and Eberlein W (2000) Pharmacological profile of BIBN4096BS, the first selective small molecule CGRP antagonist. Br J Pharmacol 129: 420–423.[CrossRef][Medline]

Edvinsson L (2003) New therapeutic target in primary headaches—blocking the CGRP receptor. Expert Opin Ther Targets 7: 377–383.[Medline]

Edvinsson L, Sams A, Jansen-Olesen I, Tajti J, Kane SA, Rutledge RZ, Koblan KS, Hill RG, and Longmore J (2001) Characterisation of the effects of a non-peptide CGRP receptor antagonist in SK-N-MC cells and isolated human cerebral arteries. Eur J Pharmacol 415: 39–44.[CrossRef][Medline]

Evans BN, Rosenblatt MI, Mnayer LO, Oliver KR, and Dickerson IM (2000) CGRP-RCP, a novel protein required for signal transduction at calcitonin gene-related peptide and adrenomedullin receptors. J Biol Chem 275: 31438–31443.[Abstract/Free Full Text]

Fischer MJM, Koulchitsky S, and Messlinger K (2005) The nonpeptide calcitonin gene-related peptide receptor antagonist BIBN4096BS lowers the activity of neurons with meningeal input in the rat spinal trigeminal nucleus. J Neurosci 25: 5877–5883.[Abstract/Free Full Text]

Goadsby PJ and Edvinsson L (1993) The trigeminovascular system and migraine: studies characterizing cerebrovascular and neuropeptide changes seen in humans and cats. Ann Neurol 33: 48–56.[CrossRef][Medline]

Goadsby PJ, Edvinsson L, and Ekman R (1990) Vasoactive peptide release in the extracerebral circulation of humans during migraine headache. Ann Neurol 28: 183–187.[CrossRef][Medline]

Goadsby PJ, Lipton RB, and Ferrari MD (2002) Migraine—current understanding and treatment. N Engl J Med 346: 257–270.[Free Full Text]

Hargreaves R (2007) New migraine and pain research. Headache 47: S26–S43.[CrossRef][Medline]

Hasbak P, Sams A, Schifter S, Longmore J, and Edvinsson L (2001) CGRP receptors mediating CGRP-, adrenomedullin- and amylin-induced relaxation in porcine coronary arteries. Characterization with Compound 1' (W098/11128), a non-peptide antagonist. Br J Pharmacol 133: 1405–1413.[CrossRef][Medline]

Hershey JC, Corcoran HA, Baskin EP, Salvatore CA, Mosser S, Williams TM, Koblan KS, Hargreaves RJ, and Kane SA (2005) Investigation of the species selectivity of a nonpeptide CGRP receptor antagonist using a novel pharmacodynamic assay. Regul Pept 127: 71–77.[CrossRef][Medline]

Ho TW, Mannix LK, Fan X, Assaid C, Furtek C, Jones CJ, Lines CR, and Rapoport AM (2007) Randomized controlled trial of an oral CGRP receptor antagonist, MK-0974, in acute treatment of migraine. Neurology, in press.

Institute of Laboratory Animal Resources (1996) Guide for the Care and Use of Laboratory Animals 7th ed. Institute of Laboratory Animal Resources, Commission on Life Sciences, National Research Council, Washington DC.

Juhasz G, Zsombok T, Modos EA, Olajos S, Jakab B, Nemeth J, Szolcsanyi J, Vitrai J, and Bagdy G (2003) NO-induced migraine attack: strong increase in plasma calcitonin gene-related peptide (CGRP) concentration and negative correlation with platelet serotonin release. Pain 106: 461–470.[CrossRef][Medline]

Lassen LH, Jacobsen VB, Petersen P, Sperling B, Iversen HK, and Olesen J (1998) Human calcitonin gene-related peptide (hCGRP)-induced headache in migraineurs. Eur J Neurol 5: S63.

Levy D, Burstein R, and Strassman AM (2005) Calcitonin gene-related peptide does not excite or sensitize meningeal nociceptors: implications for the pathophysiology of migraine. Ann Neurol 58: 698–705.[CrossRef][Medline]

Lin Q, Wu J, and Willis WD (1999) Dorsal root reflexes and cutaneous neurogenic inflammation after intradermal injection of capsaicin in rats. J Neurophysiol 82: 2602–2611.[Abstract/Free Full Text]

Mallee JJ, Salvatore CA, LeBourdelles B, Oliver KR, Longmore J, Koblan KS, and Kane SA (2002) Receptor activity-modifying protein 1 determines the species selectivity of non-peptide CGRP receptor antagonists. J Biol Chem 277: 14294–14298.[Abstract/Free Full Text]

McLatchie LM, Fraser NJ, Main MJ, Wise A, Brown J, Thompson N, Solari R, Lee MG, and Foord SM (1998). RAMPs regulate the transport and ligand specificity of the calcitonin-receptor-like receptor. Nature 393: 333–339.[CrossRef][Medline]

Olesen J, Diener HC, Husstedt IW, Goadsby PJ, Hall D, Meier U, Pollentier S, and Lesko LM (2004) Calcitonin gene-related peptide receptor antagonist BIBN 4096 BS for the acute treatment of migraine. N Engl J Med 350: 1104–1110.[Abstract/Free Full Text]

Paone DV, Shaw AW, Nguyen DN, Burgey CS, Deng JZ, Kane SA, Koblan KS, Salvatore CA, Mosser SD, Johnston VK, et al. (2007) Potent, orally bioavailable calcitonin gene-related peptide receptor antagonists for the treatment of migraine: discovery of N-[(3R,6S)-6-(2,3-difluorophenyl)-2-oxo-1-(2,2,2-trifluoroethyl)azepan-3-yl]-4-(2-oxo-2,3-dihydro-1H-imidazo[4,5-b]pyridin-1-yl)piperidine-1-carboxamide (MK-0974). J Med Chem 50: 5564–5567.[CrossRef][Medline]

Petersen KA, Birk S, Lassen LH, Kruuse C, Jonassen O, and Olesen J (2003) The novel CGRP-antagonist, BIBN4096BS does not affect the cerebral hemodynamics in healthy volunteers. Cephalalgia 23: 729.

Semark JE, Middlemiss DN, and Hutson PH (1992) Comparison of calcitonin gene-related peptide receptors in rat brain and a human neuroblastoma cell-line SK-N-MC. Mol Neuropharmacol 2: 311–317.

Sinclair SR, Kane SA, Xiao A, Willson KJ, Xu Y, Hickey L, Palcza J, de Lepeleire I, Vanmolkot F, de Hoon J, et al. (2007) MK-0974 oral CGRP antagonist inhibits capsaicin-induced increases in dermal microvascular blood flow. Headache 47: 811.

Storer RJ, Akerman S, and Goadsby PJ (2004) Calcitonin gene-related peptide (CGRP) modulates nociceptive trigeminovascular transmission in the cat. Br J Pharmacol 142: 1171–1181.[CrossRef][Medline]

van Rossum D, Hanisch, U-K, and Quirion R (1997) Neuroanatomical localization, pharmacological characterization and functions of CGRP, related peptides and their receptors. Neurosci Biobehav Rev 21: 649–678.[CrossRef][Medline]

Williams TM, Stump CA, Nguyen DN, Quigley AG, Bell IM, Gallicchio SN, Zartman CB, Wan B-L, Della Penna K, Kunapuli P, et al. (2006) Non-peptide calcitonin gene-related peptide receptor antagonists from a benzodiazepinone lead. Bioorg Med Chem Lett 16: 2595–2598.[CrossRef][Medline]

This article has been cited by other articles:

				C. P. Regan, G. L. Stump, S. A. Kane, and J. J. Lynch Jr. Calcitonin Gene-Related Peptide Receptor Antagonism Does Not Affect the Severity of Myocardial Ischemia during Atrial Pacing in Dogs with Coronary Artery Stenosis J. Pharmacol. Exp. Ther., February 1, 2009; 328(2): 571 - 578. [Abstract] [Full Text] [PDF]

				B. J. Van der Schueren, A. Rogiers, F. H. Vanmolkot, A. Van Hecken, M. Depre, S. A. Kane, I. De Lepeleire, S. R. Sinclair, and J. N. de Hoon Calcitonin Gene-Related Peptide8-37 Antagonizes Capsaicin-Induced Vasodilation in the Skin: Evaluation of a Human in Vivo Pharmacodynamic Model J. Pharmacol. Exp. Ther., April 1, 2008; 325(1): 248 - 255. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Data Supplement All Versions of this Article: jpet.107.130344v1 324/2/416    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Salvatore, C. A. Articles by Kane, S. A. Search for Related Content PubMed PubMed Citation Articles by Salvatore, C. A. Articles by Kane, S. A.