[N-methyl-3H3]AZ10419369 Binding to the 5-HT1BReceptor: In Vitro Characterization and in Vivo Receptor Occupancy

Maier, Donna L.; Sobotka-Briner, Cindy; Ding, Min; Powell, Mark; Jiang, Qiongqiong; Hill, Geraldine; Heys, J. Richard; Elmore, Charles S.; Pierson, M. Edward; Mrzljak, Ladislav

doi:10.1124/jpet.109.150722

Cited by 30 publications

(29 citation statements)

References 29 publications

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“…First, postmortem autoradiography studies have showed that the 5-HT 1B receptor density is negligible in the CB of the primate brain (Varnäs et al, 2001(Varnäs et al, , 2004. Second, pretreatment studies with 5-HT 1B receptor antagonists have shown no evident effect on [ 11 C]AZ10419369 binding in the CB of guinea-pig and monkey (Maier et al, 2009;Pierson et al, 2008). Third, the cerebellar distribution volume (V ND ) did not decrease after oral administration of the 5-HT 1B receptor antagonist AZD3783 in man (Varnäs et al, 2011b).…”

Section: Discussionmentioning

confidence: 99%

Confirmation of Fenfluramine Effect on 5-HT_1B Receptor Binding of [¹¹C]AZ10419369 using an Equilibrium Approach

Finnema

Varrone

Hwang

et al. 2011

J Cereb Blood Flow Metab

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Assessment of serotonin release in the living brain with positron emission tomography (PET) may have been hampered by the lack of suitable radioligands. We previously reported that fenfluramine caused a dose-dependent reduction in specific binding in monkeys using a classical displacement paradigm with bolus administration of [11 C]AZ10419369. The aim of this study was to confirm our previous findings using an equilibrium approach in monkey. A total of 24 PET measurements were conducted using a bolus infusion protocol of [11 C]AZ10419369 in three cynomolgus monkeys. Initial PET measurements were performed to assess suitable K bol values. The fenfluramine effect on [ 11 C]AZ10419369 binding was evaluated in a displacement and pretreatment paradigm. The effect of fenfluramine on [11 C]AZ10419369 binding potential (BP ND ) was dose-dependent in the displacement paradigm and confirmed in the pretreatment paradigm. After pretreatment administration of fenfluramine (5.0 mg/kg), the mean BP ND of the occipital cortex decreased by 39%, from 1.38 ± 0.04 to 0.84 ± 0.09. This study confirms that the new 5-HT 1B receptor radioligand [11 C]AZ10419369 is sensitive to fenfluramine-induced changes in endogenous serotonin levels in vivo. The more advanced methodology is suitable for exploring the sensitivity limit to serotonin release as measured using [11 C]AZ10419369 and PET.

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Section: Discussionmentioning

confidence: 99%

Confirmation of Fenfluramine Effect on 5-HT_1B Receptor Binding of [¹¹C]AZ10419369 using an Equilibrium Approach

Finnema

Varrone

Hwang

et al. 2011

J Cereb Blood Flow Metab

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“…Our previous results demonstrated that [N-methyl-3 H 3 ]AZ10419369 was a selective 5-HT 1B receptor ligand (Maier et al, 2009). Predose of AZD3783 reduced specific binding of [N-methyl-3 H 3 ]AZ10419369 in guinea pig brain in a dose-dependent manner (Fig.…”

Section: Pharmacologymentioning

confidence: 99%

“…The pharmacology of AZD1134 was well defined, and it demonstrated structurally diversity from AZD3783 (Maier et al, 2009). The assay plates were incubated for 1 h at room temperature with shaking.…”

Section: Pharmacologymentioning

confidence: 99%

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Preclinical Pharmacology and Pharmacokinetics of AZD3783, a Selective 5-Hydroxytryptamine 1B Receptor Antagonist

Zhang¹,

Zhou²,

Wang³

et al. 2011

J Pharmacol Exp Ther

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The preclinical pharmacology and pharmacokinetic properties of (2R)-6-methoxy-8-(4-methylpiperazin-1-yl)-N-(4-morpholin-4-ylphenyl)chromane-2-carboxamide (AZD3783), a potent 5-hydroxytryptamine 1B (5-HT 1B ) receptor antagonist, were characterized as part of translational pharmacokinetic/pharmacodynamic hypothesis testing in human clinical trials. The affinity of AZD3783 to the 5-HT 1B receptor was measured in vitro by using membrane preparations containing recombinant human or guinea pig 5-HT 1B receptors and in native guinea pig brain tissue. In vivo antagonist potency of AZD3783 for the 5HT 1B receptor was investigated by measuring the blockade of 5-HT 1B agonist-induced guinea pig hypothermia. The anxiolytic-like potency was assessed using the suppression of separation-induced vocalization in guinea pig pups. The affinity of AZD3783 for human and guinea pig 5-HT 1B receptor (K i , 12.5 and 11.1 nM, respectively) was similar to unbound plasma EC 50 values for guinea pig receptor occupancy (11 nM) and reduction of agonist-induced hypothermia (18 nM) in guinea pig. Active doses of AZD3783 in the hypothermia assay were similar to doses that reduced separation-induced vocalization in guinea pig pups. AZD3783 demonstrated favorable pharmacokinetic properties. The predicted pharmacokinetic parameters (total plasma clearance, 6.5 ml/min/kg; steady-state volume of distribution, 6.4 l/kg) were within 2-fold of the values observed in healthy male volunteers after a single 20-mg oral dose. This investigation presents a direct link between AZD3783 in vitro affinity and in vivo receptor occupancy to preclinical disease model efficacy. Together with predicted human pharmacokinetic properties, we have provided a model for the quantitative translational pharmacology of AZD3783 that increases confidence in the optimal human receptor occupancy required for antidepressant and anxiolytic effects in patients.

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“…For studies of 5-HT 1B receptor binding, we performed incubations with the radioligand [ 3 H]AZ10419369 (Maier et al, 2009) at concentration 0.3 nM and increasing concentrations (0.01 nM-1 mM) of AZD3676 in 50 mM Tris-HCl buffer, pH 7.4, containing 4 mM CaCl 2 , 4 mM MgCl 2 , and 1 mM EDTA. Nonspecific binding was determined in the presence of 1 mM methiothepin.…”

Section: In Vitro Pharmacologic Characterizationmentioning

confidence: 99%

Integrated Strategy for Use of Positron Emission Tomography in Nonhuman Primates to Confirm Multitarget Occupancy of Novel Psychotropic Drugs: An Example with AZD3676

Varnäs

Johnström

Ahlgren

et al. 2016

Journal of Pharmacology and Experimental Therapeutics

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Positron emission tomography (PET) is widely applied in central nervous system (CNS) drug development for assessment of target engagement in vivo. As the majority of PET investigations have addressed drug interaction at a single binding site, findings of multitarget engagement have been less frequently reported and have often been inconsistent with results obtained in vitro. AZD3676 [N,N-dimethyl-7-(4-(2-(pyridin-2-yl)ethyl)piperazin-1-yl) benzofuran-2-carboxamide] is a novel combined serotonin (5-hydroxytryptamine) 5-HT 1A and 5-HT 1B receptor antagonist that was developed for the treatment of cognitive impairment in Alzheimer's disease. Here, we evaluated the properties of AZD3676 as a CNS drug by combining in vitro and ex vivo radioligand binding techniques, behavioral pharmacology in rodents, and PET imaging in nonhuman primates. Target engagement in the nonhuman primate brain was assessed in PET studies by determination of drug-induced occupancy using receptorselective radioligands. AZD3676 showed preclinical properties consistent with CNS drug potential, including nanomolar receptor affinity and efficacy in rodent models of learning and memory. In PET studies of the monkey brain, AZD3676 inhibited radioligand binding in a dose-dependent manner with similar affinity at both receptors. The equally high affinity at 5-HT 1A and 5-HT 1B receptors as determined in vivo was not predicted from corresponding estimates obtained in vitro, suggesting more than 10-fold selectivity for 5-HT 1A versus 5-HT 1B receptors. These findings support the further integrated use of PET for confirmation of multitarget occupancy of CNS drugs. Importantly, earlier introduction of PET studies in nonhuman primates may reduce future development costs and the requirement for animal experiments in preclinical CNS drug development programs.

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[N-methyl-³H₃]AZ10419369 Binding to the 5-HT_1BReceptor: In Vitro Characterization and in Vivo Receptor Occupancy

Cited by 30 publications

References 29 publications

Confirmation of Fenfluramine Effect on 5-HT_1B Receptor Binding of [¹¹C]AZ10419369 using an Equilibrium Approach

Confirmation of Fenfluramine Effect on 5-HT_1B Receptor Binding of [¹¹C]AZ10419369 using an Equilibrium Approach

Preclinical Pharmacology and Pharmacokinetics of AZD3783, a Selective 5-Hydroxytryptamine 1B Receptor Antagonist

Integrated Strategy for Use of Positron Emission Tomography in Nonhuman Primates to Confirm Multitarget Occupancy of Novel Psychotropic Drugs: An Example with AZD3676

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[N-methyl-3H3]AZ10419369 Binding to the 5-HT1BReceptor: In Vitro Characterization and in Vivo Receptor Occupancy

Cited by 30 publications

References 29 publications

Confirmation of Fenfluramine Effect on 5-HT1B Receptor Binding of [11C]AZ10419369 using an Equilibrium Approach

Confirmation of Fenfluramine Effect on 5-HT1B Receptor Binding of [11C]AZ10419369 using an Equilibrium Approach

Preclinical Pharmacology and Pharmacokinetics of AZD3783, a Selective 5-Hydroxytryptamine 1B Receptor Antagonist

Integrated Strategy for Use of Positron Emission Tomography in Nonhuman Primates to Confirm Multitarget Occupancy of Novel Psychotropic Drugs: An Example with AZD3676

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[N-methyl-³H₃]AZ10419369 Binding to the 5-HT_1BReceptor: In Vitro Characterization and in Vivo Receptor Occupancy

Confirmation of Fenfluramine Effect on 5-HT_1B Receptor Binding of [¹¹C]AZ10419369 using an Equilibrium Approach

Confirmation of Fenfluramine Effect on 5-HT_1B Receptor Binding of [¹¹C]AZ10419369 using an Equilibrium Approach