Ethanol Is a Fast Channel Inhibitor of P2X4 Receptors

Ostrovskaya, Olga; Asatryan, Liana; Wyatt, Letisha R.; Popova, Maya; Li, Kaixun; Peoples, Robert W.; Alkana, Ronald L.; Davies, Daryl L.

doi:10.1124/jpet.110.176990

Cited by 39 publications

(47 citation statements)

References 43 publications

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“…Furthermore, these receptors are localized in key brain regions associated with alcohol consumption and reinforcement, such as the ventral tegmental area (VTA) and nucleus accumbens (NAc); i.e., the mesolimbic reward pathway (Pierce et al, 2006; Xiao et al, 2008). Findings indicate that intoxicating and anesthetic ethanol (EtOH) doses desensitize the response of P2X4R-expressing cell lines to ATP exposure (Li et al, 1993; Xiong et al, 2000; Davies et al, 2005; Ostrovskaya et al, 2011), suggesting EtOH alters the effects of these receptors on modulating neurotransmission. This effect likely occurs in part at P2X4R ectodomain-transmembrane segment interfaces (Lalo et al 2007; Asatryan et al, 2008), as the inhibitory effect of EtOH on P2X4Rs may be reversed by point mutations in these areas (Popova et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Involvement of Purinergic P2X4 Receptors in Alcohol Intake of High-Alcohol-Drinking (HAD) Rats

Franklin

Hauser

Lasek

et al. 2015

Alcohol Clin Exp Res

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Background The P2X4 receptor is thought to be involved in regulating alcohol-consuming behaviors and ethanol (EtOH) has been reported to inhibit P2X4 receptors. Ivermectin is an anti-parasitic agent that acts as a positive allosteric modulator of the P2X4 receptor. The current study examined the effects of systemically- and centrally-administered ivermectin on alcohol drinking of replicate lines of high-alcohol-drinking (HAD-1/HAD-2) rats, and the effects of lentiviral-delivered short-hairpin RNAs (shRNAs) targeting P2rx4 on EtOH intake of female HAD2 rats. Method For the 1st experiment, adult male HAD-1 & HAD-2 rats were given 24-hr free-choice access to 15% EtOH vs. water. Dose-response effects of ivermectin (1.5 to 7.5 mg/kg i.p.) on EtOH intake were determined; the effects of ivermectin were then examined for 2% w/v sucrose intake over 5 consecutive days. In the 2nd experiment, female HAD-2 rats were trained to consume 15% EtOH under 2-hr limited access conditions, and dose-response effects of intracerebroventricular (ICV) administration of ivermectin (0.5 to 2.0 μg) were determined over 5 consecutive days. The 3rd experiment determined the effects of microinfusion of a lentivirus expressing P2rx4 shRNAs into the posterior ventral tegmental area (VTA) on 24-hr EtOH free-choice drinking of female HAD-2 rats. Results The highest i.p. dose of ivermectin reduced alcohol drinking (30-45%) in both rat lines, but did not alter sucrose intake. HAD-2 rats appeared to be more sensitive than HAD1 rats to the effects of ivermectin. ICV administration of ivermectin reduced 2-hr limited access intake (∼35%) of female HAD-2 rats; knockdown of P2rx4 expression in the posterior VTA reduced 24-hr free choice EtOH intake (∼20%). Conclusion Overall, the results of the current study support a role for P2X4 receptors within the mesolimbic system in mediating alcohol drinking behavior.

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Section: Introductionmentioning

confidence: 99%

Involvement of Purinergic P2X4 Receptors in Alcohol Intake of High-Alcohol-Drinking (HAD) Rats

Franklin

Hauser

Lasek

et al. 2015

Alcohol Clin Exp Res

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“…P2X receptors are ubiquitously expressed ligand-gated cation channels that mediate a remarkable variety of physiological and pathophysiological reactions, especially in microglia 16-20, 26 . More recently, purinergic receptors have been implicated in alcohol abuse disorders, affecting signaling in the CNS 27, 28 . Studies have shown that alcohol acts as an allosteric regulator inhibiting P2X4R function most likely operating through interactions with the TM domains or hydrophobic regions within the channel structure 29 .…”

Section: Introductionmentioning

confidence: 99%

“…Ethanol inhibits ATP-activated currents in rat and mouse neurons, suggesting a role for P2X4R in ethanol-related behaviors. While building evidence supports a role for P2X4R in the action of alcohol 28 , their role in modulating the functional activities of microglia is unknown.…”

Section: Introductionmentioning

confidence: 99%

P2X4 Receptor Regulates Alcohol-Induced Responses in Microglia

Gofman

Cenna

Potula

2014

J Neuroimmune Pharmacol

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Mounting evidence indicates that alcohol-induced neuropathology may result from multicellular responses in which microglia cells play a prominent role. Purinergic receptor signaling plays a key role in regulating microglial function and, more importantly, mediates alcohol-induced effects. Our findings demonstrate that alcohol increases expression of P2X4 receptor (P2X4R), which alters the function of microglia, including calcium mobilization, migration and phagocytosis. Our results show a significant up-regulation of P2X4 gene expression as analyzed by real-time qPCR (***p<0.002) and protein expression as analyzed by flow cytometry (**p<0.004) in embryonic stem cell-derived microglial cells (ESdM) after 48 hours of alcohol treatment, as compared to untreated controls. Calcium mobilization in ethanol treated ESdM cells was found to be P2X4R dependent using 5-BDBD, a P2X4R selective antagonist. Alcohol decreased migration of microglia towards fractalkine (CX3CL1) by 75% following 48 hours of treatment compared to control (***p<0.001). CX3CL1-dependent migration was confirmed to be P2X4 receptor-dependent using the antagonist 5-BDBD, which reversed the effects as compared to alcohol alone (***p<0.001). Similarly, 48 hours of alcohol treatment significantly decreased phagocytosis of microglia by 15% compared to control (*p<0.05). 5-BDBD pre-treatment prior to alcohol treatment significantly increased microglial phagocytosis (***p<0.001). Blocking P2X4R signaling with 5-BDBD decreased the level of calcium mobilization compared to ethanol treatment alone. These findings demonstrate that P2X4 receptor may play a role in modulating microglial function in the context of alcohol abuse.

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“…The P2X4R and to some extent also the P2X2R are positively modulated by high concentrations of ethanol (ca. 100 mM) (Yi et al, 2009; Ostrovskaya et al, 2011). …”

Section: P2xr Modulatorsmentioning

confidence: 99%

Medicinal chemistry of adenosine, P2Y and P2X receptors

2016

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Pharmacological tool compounds are now available to define action at the adenosine (ARs), P2Y and P2X receptors. We present a selection of the most commonly used agents to study purines in the nervous system. Some of these compounds, including A1 and A3 AR agonists, P2Y1R and P2Y12R antagonists, and P2X3, P2X4 and P2X7 antagonists, are potentially of clinical use in treatment of disorders of the nervous system, such as chronic pain, neurodegeneration and brain injury. Agonists of the A2AAR and P2Y2R are already used clinically, P2Y12R antagonists are widely used antithrombotics and an antagonist of the A2AAR is approved in Japan for treating Parkinson’s disease. The selectivity defined for some of the previously introduced compounds has been revised with updated pharmacological characterization, for example, various AR agonists and antagonists were deemed A1AR or A3AR selective based on human data, but species differences indicated a reduction in selectivity ratios in other species. Also, many of the P2R ligands still lack bioavailability due to charged groups or hydrolytic (either enzymatic or chemical) instability. X-ray crystallographic structures of AR and P2YRs have shifted the mode of ligand discovery to structure-based approaches rather than previous empirical approaches. The X-ray structures can be utilized either for in silico screening of chemically diverse libraries for the discovery of novel ligands or for enhancement of the properties of known ligands by chemical modification. Although X-ray structures of the zebrafish P2X4R have been reported, there is scant structural information about ligand recognition in these trimeric ion channels. In summary, there are definitive, selective agonists and antagonists for all of the ARs and some of the P2YRs; while the pharmacochemistry of P2XRs is still in nascent stages. The therapeutic potential of selectively modulating these receptors is continuing to gain interest in such fields as cancer, inflammation, pain, diabetes, ischemic protection and many other conditions. Reported potencies refer to the human receptors unless otherwise noted. Additional affinity data can be found in recent review papers (Müller and Jacobson, 2011; Jacobson et al., 2015; Coddou et al., 2011a).

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Ethanol Is a Fast Channel Inhibitor of P2X4 Receptors

Cited by 39 publications

References 43 publications

Involvement of Purinergic P2X4 Receptors in Alcohol Intake of High-Alcohol-Drinking (HAD) Rats

Involvement of Purinergic P2X4 Receptors in Alcohol Intake of High-Alcohol-Drinking (HAD) Rats

P2X4 Receptor Regulates Alcohol-Induced Responses in Microglia

Medicinal chemistry of adenosine, P2Y and P2X receptors

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