作者: Khajehali, Elham ; Belousoff, Matthew J ; Danev, Radostin ; Pham, Vi ; Christopoulos, Arthur ; Glukhova, Alisa ; van der Westhuizen, Emma T ; Thompson, Geoff ; Wootten, Denise ; Mobbs, Jesse I ; Lindsley, Craig W ; Wang, Jinan ; Thal, David M ; Burger, Wessel A C ; Miao, Yinglong ; Nawaratne, Vindhya ; Tobin, Andrew ; Bhattarai, Apurba ; Sexton, Patrick ; Yeasmin, Mahmuda ; Valant, Celine ; Liang, Yi-Lynn ; Leach, Katie ; Vuckovic, Ziva

Allosteric modulation of G protein-coupled receptors (GPCRs) is a major paradigm in drug discovery. Despite decades of research, a molecular-level understanding of the general principles that govern the myriad pharmacological effects exerted by GPCR allosteric modulators remains limited. The M₄ muscarinic acetylcholine receptor (M₄ mAChR) is a validated and clinically relevant allosteric drug target for several major psychiatric and cognitive disorders. In this study, we rigorously quantified the affinity, efficacy, and magnitude of modulation of two different positive allosteric modulators, LY2033298 (LY298) and VU0467154 (VU154), combined with the endogenous agonist acetylcholine (ACh) or the high-affinity agonist iperoxo (Ipx), at the human M₄ mAChR. By determining the cryo-electron microscopy structures of the M₄ mAChR, bound to a cognate G_i1 protein and in complex with ACh, Ipx, LY298-Ipx, and VU154-Ipx, and applying molecular dynamics simulations, we determine key molecular mechanisms underlying allosteric pharmacology. In addition to delineating the contribution of spatially distinct binding sites on observed pharmacology, our findings also revealed a vital role for orthosteric and allosteric ligand-receptor-transducer complex stability, mediated by conformational dynamics between these sites, in the ultimate determination of affinity, efficacy, cooperativity, probe dependence, and species variability. There results provide a holistic framework for further GPCR mechanistic studies and can aid in the discovery and design of future allosteric drugs.

2020-09-01·European Journal of Pharmacology3区 · 医学

M3 but not M4 muscarinic receptors in the rostromedial tegmental nucleus are involved in the acquisition of morphine-induced conditioned place preference

3区 · 医学

Article

作者: Zhou, Pan ; Li, Xuhong ; Li, Xinwang ; Wu, Jing

Opioids strongly inhibit GABAergic neurons in the rostromedial tegmental nucleus (RMTg) that expresses μ-opioid receptors to induce rewarding and psychomotor effects. M₃ and M₄ muscarinic receptors are co-localized with μ-opioid receptors at these GABAergic neurons. This study explored whether RMTg M₃ and M₄ muscarinic receptors are involved in regulating opioid-induced reward and locomotion via a conditioned place preference (CPP) paradigm. Selective muscarinic receptor agonists and antagonists were both singly and combinatorically injected into the RMTg to examine their effects on the acquisition of systemic morphine-induced CPP and locomotor activity. The M₃ muscarinic receptor agonist, pilocarpine, inhibited the acquisition of morphine-induced CPP, whereas its antagonist, 1,1-dimethyl-4-diphenylacetoxypiperidinium iodide (4-DAMP, 1 μg/side), reversed the inhibitory effect of pilocarpine (30 μg/side). Additionally, 4-DAMP increased locomotor activity while pilocarpine (30 μg/side) partially decreased locomotor activity when combined with morphine. In contrast, the M₄ muscarinic receptor agonist, LY2033298 (0.1 and 0.2 μg/side), and antagonist, tropicamide (20 and 40 μM/side), did not affect the acquisition of morphine-induced CPP or locomotor activity. Taken together, our findings suggest that RMTg M₃ muscarinic receptors are involved in opioid-induced rewarding and psychomotor effects. Therefore, RMTg M₃ muscarinic receptors may represent a promising target for the treatment of opioid addiction.

2019-03-01·Behavioural Brain Research3区 · 心理学

Cholinergic M4 receptors are involved in morphine-induced expression of behavioral sensitization by regulating dopamine function in the nucleus accumbens of rats

3区 · 心理学

Article

作者: Sun, Jinling ; Li, Xinwang ; Liu, Liyuan ; Cui, Ruisi ; Ruan, Heng ; Liu, Xinhe

Repeated administration of morphine profoundly influences the dopaminergic and cholinergic systems in the nucleus accumbens [including the shell of the nucleus accumbens (NAcS)]. Further, dopamine release is regulated by the cholinergic system, especially the M₄ receptor. Drug priming is one of the main factors that induces relapse in drug addiction. The present study first investigated how activation of the M₄ receptor in the NAcS affects the expression of morphine-induced behavioral sensitization, through the administration of an M₄ agonist (LY2033298) and antagonist (tropicamide), as well as a combination of an acetylcholinesterase inhibitor and M₄ antagonist (huperzine-A + tropicamide). Additionally, the influence of a dopamine receptor agonist, in conjunction with an M₄ agonist (i.e., SKF38393 + LY2033298), was also examined. Behavioral sensitization was established by exposure to 5 mg/kg morphine once every three days for a total of three exposures. The expression of behavioral sensitization was challenged by 5 mg/kg morphine. Results showed that (1) microinjection of the M₄ receptor agonist LY2033298 (0.2 μg/side), but not the antagonist tropicamide (5, 10, or 20 μM/side) into the NAcS blocked the expression of behavioral sensitization; (2) tropicamide (20 μM/side) reversed the inhibition effect of huperzine-A on this behavior; and (3) SKF38393 (1 μg/side) reversed the inhibitory effect of LY2033298 on the expression of morphine-induced behavioral sensitization. These results suggest that the cholinergic M₄ receptor in the NAcS plays an important role in the morphine-induced expression of behavioral sensitization through the regulation of dopamine function in rats.

100 项与 LY-2033298 相关的药物交易

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