Description
MK-3207 (Hydrochloride) is a potent and orally bioavailable CGRP receptor antagonist with IC50 of 0.12 nM and Ki of 0.024 nM, and is highly selective versus human AM1, AM2, CTR, and AMY3.
Related Catalog
Signaling Pathways >> GPCR/G Protein >> CGRP Receptor
Signaling Pathways >> Neuronal Signaling >> CGRP Receptor
Research Areas >> Neurological Disease
Target
IC50: 0.12 nM (CGRP receptor)
In Vitro
MK-3207 displays a similar affinity (Ki) for the rhesus monkey receptor (0.024±0.001 nM; n=14) as for human, but it displays >400-fold lower affinity for the canine and rat receptors, with values of 10 nM and 10±1.2 nM, respectively. MK-3207 is highly selective versus the human AM1 (CLR/RAMP2) and AM2 (CLR/RAMP3) receptors, with Ki values of 16,500 nM and 156±17 nM, respectively. MK-3207 maintains a high degree of selectivity versus human CTR, with a Ki value of 1.9±0.58 μM. MK-3207 also displays good selectivity versus the AMY3 (CTR/RAMP3) receptor, with a Ki value of 128±25 nM, but it is less selective versus the AMY1 (CTR/RAMP1) receptor, with a Ki value of 0.75±0.13 nM. MK-3207 potently blocks human α-CGRP-stimulated cAMP responses in human CGRP receptor-expressing HEK293 cells, with an IC50 value of 0.12±0.02 nM. MK-3207 displays significantly lower potency for the rat CGRP receptor, with a pIC50=7.31±0.09[1].
In Vivo
MK-3207 is CNS-penetrant and therefore significantly engaging central receptors. After an oral dose of 10 mg/kg MK-3207, the CSF/plasma ratio is 2 to 3%[1].
Kinase Assay
Amylin binding assays are conducted by combining MK-3207 and 40 pM 125I-rat amylin, followed by 25 μg of CTR/RAMP1 or 25 μg of CTR/RAMP3 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. Calcitonin binding assays are with 25 μg of CTR membranes and 30 pM 125I-human calcitonin as the radioligand. Incubations are terminated by filtration through GF/B 96-well filter plates that has been blocked with 0.5% polyethylenimine. Data are analyzed using Prism, and the Ki value is determined using the equation Ki=IC50/1 + ([ligand]/KD). The KD value for each receptor is determined by saturation binding experiments.
Animal Admin
A customized flexible silicone catheter is freely suspended in the cisterna magna, anchored firmly on both sides of the atlanto-occipital membrane, and tunneled subcutaneously to the midscapular region where it is fed into a surgically implanted port body. CSF is accessed by aseptically inserting a needle through the skin and membrane covering the port into the reservoir of the port body; blood samples are collected by peripheral venipuncture. After oral administration of MK-3207 at 10 mg/kg (0.5% methylcellulose, with an adjusted pH appr 3) to cisterna magna catheter and port-implanted rhesus monkeys, CSF and plasma samples are collected at 0.5, 1, 2, 4, 8, and 24 h and analyzed for compound levels.
References
[1]. Salvatore CA, et al. Pharmacological properties of MK-3207, a potent and orally active calcitonin gene-related peptide receptor antagonist. J Pharmacol Exp Ther. 2010 Apr;333(1):152-60.
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