Application of dopamine D2 receptor G protein antagonist in preparation of medicine for treating drug addiction

Abstract

The invention belongs to the technical field of neurobiology, and particularly relates to application of a dopamine D2 receptor G protein antagonist in preparation of a drug for treating drug addiction. Researches show that the dopamine D2 receptor G protein antagonist can inhibit recurrence after drug addiction fading induced by ignition of small-dose drugs. A mouse cocaine self-administration addiction model is adopted, a small dose of cocaine is given after model mice are subjected to regression training, and the recurrence behavior of the mouse cocaine addiction after regression is induced. A signal channel dependent on dopamine D2 receptor downstream G protein is inhibited before addiction recurrence is induced by a small dose of cocaine, and recurrence after drug-induced cocaine fading can be inhibited; however, the signal pathway for inhibiting the dependence of beta-arretin on the downstream of the dopamine D2 receptor cannot inhibit the recurrence after drug-induced cocaine fading. The invention discloses the effect of the G protein biased antagonist of the dopamine D2 receptor in treatment of drug addiction, and provides a new thought and a drug intervention target for treatment of drug addiction of cocaine and the like.

Description

Technical Field

[0001] This invention belongs to the field of neurobiology, specifically relating to the use of dopamine D2 receptor G protein signaling pathway antagonists in the preparation of drugs for treating drug addiction. Background Technology

[0002] Drug addiction is a chronic, relapsing brain disorder characterized by compulsive drug use and a high relapse rate. The development from drug use to addiction progresses through four stages: occasional drug use, recreational drug use, regular drug use, and drug addiction. Once addiction is established, even after long-term withdrawal or regression training, relapse can occur when the addict returns to a similar drug-using environment, experiences a stressful event, or is exposed to small doses of the drug, leading to intense cravings and relapse behavior. Despite extensive research on the treatment of relapse, the high relapse rate remains a major challenge in treating drug addiction. As early as the 1860s, specific brain region lesions were clinically used, which to some extent suppressed relapse, but produced unbearable sequelae such as cognitive impairment and mood disorders. In the last century, psychotherapy and pharmacology were widely used to treat drug addiction, but even after treatment, the relapse rate remained as high as 50-70%. Therefore, it is still necessary to explore the neurobiological mechanisms behind addiction relapse in order to provide new ideas for the development of drugs to treat cocaine addiction.

[0003] The mesolimbic dopamine system is mainly composed of the ventral tegmental area (VTA) and the nucleus accumbens (NAc). Addictive drugs act on the mesolimbic dopamine system, leading to abnormal release of dopamine (DA) from the NAc; this is a common characteristic of all addictive drugs. For example, cocaine competitively inhibits dopamine transporters, thus blocking dopamine reuptake; amphetamine increases intersynaptic dopamine levels by promoting vesicle release; and opioids inhibit γ-aminobutyric acid (GABA) interneurons in the VTA by activating μ-opioid receptors, thus disinhibiting VTA dopaminergic neurons. Addictive drugs cause an increase in NAc dopamine concentration, activating dopamine D1 receptors (D1R), inducing euphoria and reinforcing behavior, while simultaneously inhibiting dopamine D2 receptors (D2R) and maximizing the reward effect. Long-term use of addictive drugs can lead to an imbalance in the neurotransmitter system, such as dopamine, causing addicts to have a strong craving for the drug and compulsive use behavior. This is the basis for relapse after drug withdrawal and extinction training.

[0004] Among drug addicts, cocaine addicts exhibit strong psychological dependence and a high relapse rate. Animal models of cocaine self-administration are the most commonly used to study cocaine addiction relapse. Experimental animals, such as mice, acquire the drug through a conditioned performance (nasal contact with an effective orifice), thus associating the conditioned performance with cocaine. The number of conditioned performances reflects the degree of cocaine craving. Repeated conditioned performances without drug stimulation lead to extinction of cocaine self-administration. After extinction training, small doses of cocaine can induce cocaine cravings in mice, thus simulating the post-expiration relapse phenomenon in humans. Using the post-expiration relapse model of cocaine self-administration, it was found that tyrosine hydroxylase inhibitors inhibit low-dose cocaine-induced post-expiration relapse by blocking dopamine synthesis. Pharmacological interventions activating D2R can induce cocaine addiction relapse in mice, while inhibiting D2R can inhibit cocaine addiction relapse. Dopamine receptors belong to the G protein-coupled receptor (GPCR) family. When ligands act on dopamine, they induce conformational changes in the dopamine receptor by coupling with heterotrimeric G proteins, promoting the activation of adenylate cyclase (AC), thereby increasing or decreasing the level of cyclic adenosine monophosphate (cAMP). Then, GPCR kinases (GRKs) recognize and phosphorylate the receptor, triggering the recruitment of β-arrestin, thereby blocking receptor-coupled G proteins and terminating G protein-dependent signaling pathway activation. Simultaneously, β-arrestin, as a multifunctional scaffold protein, interacts with various protein chaperones and kinases, inducing β-arrestin-dependent intracellular signaling pathway activation. The roles of downstream G proteins and β-arrestin-mediated signaling pathways in cocaine remodeling remain unclear. Summary of the Invention

[0005] The purpose of this invention is to provide the use of dopamine D2 receptor G protein signaling pathway antagonists in the preparation of drugs for treating drug addiction.

[0006] This invention explores the roles of downstream G proteins of the D2R pathway and the β-arrestin receptor signaling pathway in the relapse of cocaine addiction induced by low-dose cocaine ignition through pharmacological intervention. This provides new insights into the mechanism of cocaine addiction relapse and, consequently, offers targets and directions for the development of therapeutic drugs for cocaine addiction. Therefore:

[0007] This invention provides the use of a dopamine D2R G protein signaling pathway antagonist in the preparation of a drug addiction treatment drug. The drug addiction treatment addresses the relapse of drug addiction after its initial resolution by administering a small dose of the drug to ignite drug cravings, thereby inducing drug-seeking behavior. The dopamine D2R G protein antagonist can inhibit the relapse of drug addiction induced by a small dose of the drug after its resolution. Specifically:

[0008] This invention employs a mouse model of cocaine self-administration followed by relapse. In this model, mice acquire the drug through a conditioned performance (nasal touch of the effective orifice), thus associating nasal touch behavior with cocaine. Repeated nasal touch without drug stimulation leads to the extinction of cocaine self-administration and a decrease in the frequency of nasal touches. After extinction, stress or a small dose of cocaine can induce a craving for cocaine (relapse).

[0009] This invention found that administering the D2R agonist quinpirole before injecting a small dose of cocaine did not affect the enhanced cocaine craving induced by the burning of a small dose of cocaine, while the D2R complete antagonist racloprid significantly inhibited the enhanced cocaine craving induced by the burning of a small dose of cocaine (generally below 7.5 mg / kg, the same below), suggesting that inhibiting the D2R signaling pathway can inhibit relapse after the expiration of cocaine addiction induced by the burning of a small dose of cocaine. UNC9994, UNC9975, and UNC0006 are D2R G protein antagonists and β-arrestin agonists, which can significantly inhibit relapse after the expiration of cocaine addiction induced by a small dose of cocaine. However, the D2R G protein agonist and β-arrestin antagonist MLS1547 did not affect the enhanced cocaine craving induced by a small dose of cocaine. Furthermore, UNC9994, UNC9975, and UNC0006 had no significant effect on motor performance or anxiety levels. These results suggest that D2R primarily participates in the reconstitution of low-dose cocaine addiction induced by ignition through downstream G protein-dependent signaling pathways.

[0010] This invention reveals that inhibiting the downstream G protein signaling pathway of D2R can reduce the increase in c-Fos expression in NAc neurons induced by low-dose cocaine ignition. Pre-administration of D2R G protein antagonists UNC9994, UNC9975, and UNC0006 can inhibit the increase in c-Fos expression in NAc neurons induced by cocaine, while the D2R β-arrestin antagonist MLS1547 has no effect on the increase in c-Fos expression in NAc neurons induced by cocaine. These results suggest that the D2R G protein-dependent signaling pathway mediates cocaine-induced activation of NAc neurons.

[0011] In this invention, the therapeutic agent also includes any pharmaceutically acceptable salt, solvate, or prodrug formulation of a dopamine D2R G protein antagonist.

[0012] The present invention also provides a pharmaceutical composition for the treatment of drug addiction relapse, comprising a dopamine D2R G protein antagonist or a pharmaceutically acceptable salt, solvate or prodrug thereof.

[0013] In this invention, the drug can be used in the form of a sterile injection or an intravenous drip.

[0014] Advantages of this invention: Racloprid is a first-generation clinical antipsychotic drug, a complete D2R antagonist that inhibits the D2R G protein and β-arrestin signaling pathway. UNC9994, UNC9975, and UNC0006 are derivatives of the third-generation antipsychotic drug aripiprazole, which antagonize the D2R G protein and activate the β-arrestin signaling pathway, and are biased antagonists of the dopamine D2 receptor. Therefore, these derivatives have fewer side effects, a higher safety profile, and the potential to become clinical drugs. We found that racloprid and UNC9994, UNC9975, and UNC0006 can significantly inhibit relapse after the expiration of low-dose cocaine addiction induced by cocaine ignition. Racloprid is already a clinical drug and has the potential to become an effective treatment for drug addiction; however, its inhibition of the β-arrestin signaling pathway may produce certain side effects. UNC9994, UNC9975, UNC0006, and future D2R-biased G protein inhibitors may become a new generation of effective drugs for treating drug addiction, and could also be used to formulate drug preparations for treating mental disorders without significant side effects such as anxiety. Attached Figure Description

[0015] Figure 1 Intraperitoneal injection of a low dose of cocaine (7.5 mg / kg) induced an increased craving for cocaine in mice, and the dopamine D2R complete antagonist Raclopride inhibited the increased craving induced by the low dose of cocaine, while the dopamine D2R complete agonist Quinpirole had no significant effect.

[0016] Figure 2 The dopamine D2R G protein antagonists / β-arrestin agonists UNC9994, UNC9975, and UNC0006 can inhibit the increase in craving induced by low doses of cocaine.

[0017] Figure 3 UNC9994, UNC9975, and UNC0006 did not affect the activity and anxiety levels of mice.

[0018] Figure 4The MLS1547 dopamine D2R G protein agonist / β-arrestin antagonist had no significant effect on the increase in craving induced by low doses of cocaine.

[0019] Figure 5 MLS1547 did not affect the activity and anxiety levels of mice.

[0020] Figure 6 UNC9994, UNC9975, and UNC0006 can inhibit the increase in NAc neuron activity induced by cocaine, while MLS1547 has no significant effect.

[0021] Figure 7 To summarize: UNC9994, UNC9975, and UNC0006 inhibit drug-ignition-induced cocaine addiction relapse by suppressing the downstream G protein signaling pathway of D2R, while MLS1547 does not affect drug-ignition-induced cocaine addiction relapse by inhibiting the downstream β-arrestin signaling pathway of D2R. Detailed Implementation

[0022] Experimental Materials and Methods

[0023] 1. Laboratory animals

[0024] Clean-grade adult male C57BL / 6J mice were purchased from Shanghai Slack Laboratory Animal Co., Ltd. At the time of the animal experiments, the mice were 8-10 weeks old and weighed approximately 25-28g. Prior to self-administered intravenous catheterization, they were housed in the laboratory's animal facility in a room with reversed day-night cycles, with 12 hours of light and 12 hours of darkness (8:00-20:00 at night and 20:00-8:00 the next day). They were allowed free access to food, and the room temperature was 20-22℃ with a humidity of 55±5%. All animal husbandry and procedures during the experiments strictly adhered to the regulations for the management of laboratory animals.

[0025] 2. Model for reconstructing cocaine autodrug administration after drug ignition-induced extinction.

[0026] 2.1 Cocaine Autodrug Training

[0027] First, mice were placed in a training box for self-feeding training. Each mouse received a sugar pill (FR1) by touching the effective orifice with its nose. Training sessions lasted one hour each time for one week to ensure the mice learned to distinguish between effective and ineffective orifices. After training, the mice underwent jugular vein cannulation under isoflurane anesthesia. Post-operatively, the cannula was flushed daily with heparin solution (30 IU) containing gentamicin sulfate (0.33 mg / ml) to prevent blockage. After a one-week recovery period, self-administration training was initiated.

[0028] Mice were trained to self-administer cocaine in a self-dosing box for 2 hours daily, with the implanted tube flushed with heparin before and after each training session. During training days 1-5, mice received an intravenous injection of cocaine solution with each nasal touch of an effective orifice (FR1). From days 6-10, mice received an intravenous injection of cocaine with every three nasal touches of effective orifices (FR3). Each administration volume was 0.1 ml, lasting for two seconds, with a final training dose of 0.5 mg / kg. Each administration was accompanied by light and sound cues: the self-dosing box light went out, an indicator light above the nasal touch orifice illuminated, and a 2.9 kHz sound was emitted. These cues lasted for 10 seconds. During these 10 seconds, nasal touches of effective orifices did not elicit any response, but the number of touches was recorded. No cocaine or light / sound cues were administered to ineffective orifices. To prevent cocaine overdose and death, each mouse was given a maximum of 50 administrations, after which training was terminated prematurely.

[0029] 2.2 Cocaine Extinction Training and Extinction Testing

[0030] After auto-administration training, nasal puncture extinction training was conducted from days 11 to 20. During nasal puncture extinction training, touching either the effective or ineffective puncture with the nose did not elicit drug administration or light and sound stimulation. Each training session lasted 1 hour and was conducted twice daily. On day 21, light and sound cue extinction was conducted. The mice were placed in a training box, and after 2 minutes of adaptation, light and sound cues were induced for 10 seconds every 30 seconds, for a total of 60 cycles. On day 22, a 1-hour extinction test was conducted. During the test, touching the effective puncture with the nose elicited light and sound stimulation but did not elicit drug administration, while touching the ineffective puncture did not elicit any response. The number of times the effective puncture was touched during the test was recorded to determine the cocaine extinction status of the mice.

[0031] 2.3 Reconstruction Test

[0032] Twenty-four hours after the extinction test, a cocaine-induced reactivation test was conducted. Mice were moved to the test room for at least 60 minutes to acclimatize before the reactivation test. After an intraperitoneal injection of cocaine solution (7.5 mg / kg), the mice were placed in the training device, and the reactivation test began immediately. During the reactivation test, the mice were stimulated with light and sound cues via effective nostril contact, but no cocaine was administered. The reactivation test lasted for one hour, and the number of effective nostril contacts was recorded. The number of effective nostril contacts was used to determine whether the mice exhibited cocaine relapse.

[0033] 3. Open fieldtest (OFT)

[0034] For three consecutive days prior to the test, mice were placed in the test room for at least 60 minutes to acclimatize. On the day of the test, the mice were placed in the test room after acclimatization before the test began. The open field box measured 40cm × 40cm × 40cm, with a light intensity of 25 lux. Mice were placed in the central area of ​​the open field box, and a camera on the ceiling recorded the mice's movement within the box for 30 minutes. Noduls software was used to analyze the data, calculating the distances and dwell times of the mice in the edge and central areas of the open field box. The central area was defined as 25% of the area in the center of the open field box.

[0035] 4. Elevated plus maze test (EPM)

[0036] For three consecutive days prior to the test, mice were placed in the test room for at least 60 minutes to acclimatize. On the day of the test, after acclimatization, the mice were placed in the test room and the test began. The elevated cross maze used in the test had two open arms and two closed arms, with a light intensity of 25 lux in the open arms. During the test, the mice were placed in the central area of ​​the cross, with their heads facing the open arms, and allowed to explore freely in the device for 6 minutes. A camera on the ceiling of the room recorded the movement of the mice in the elevated cross maze. Noduls software was used to analyze and calculate the time the mice spent in the open and closed arms.

[0037] 5. Immunohistochemistry

[0038] Mice were anesthetized with isoflurane gas and perfused with physiological saline and 4% paraformaldehyde (PFA) to remove their brains. The brains were fixed in 4% PFA at 4°C for 4 hours, then transferred to 30% sucrose / PBS solution for dehydration for 3 days. Brain slices were prepared to a thickness of 30 μm using frozen cuts, washed three times with PBS, and incubated overnight at 4°C with primary antibody (anti-c-Fos, 1:500). After rinsing with PBS, the slices were incubated at room temperature with the fluorescently conjugated secondary antibody Alexa-488 for 2 hours. Anti-quenching mounting medium was added to the slices, and covers with a coverslip.

[0039] Example:

[0040] 1. Establish a relapse model after cocaine self-administration induced by low-dose ignition.

[0041] We used C57BL / 6J mice to establish a low-dose cocaine ignition-induced cocaine self-administration regression and relapse model. The self-administration and regression training were as described above. Twenty-four hours after the regression test, the experimental group received an intraperitoneal injection of 7.5 mg / kg cocaine solution, while the control group received an equal volume of physiological saline. Relapse testing was then performed. Figure 1 a).

[0042] During training, mice were able to distinguish between effective and ineffective pores. After extinction training, the number of effective nose touches during the extinction test was significantly reduced. Figure 1 bc). The test results showed that intraperitoneal injection of a small dose of cocaine significantly increased the number of nasal touches to the effective orifice in mice, while injection of physiological saline did not significantly increase the number of nasal touches to the effective orifice in mice. Figure 1 d: Scheiger-Ray-Hare test, H groups×session(1,23) =8.985, P=0.003). This demonstrates that low-dose cocaine can effectively induce cocaine cravings in mice after remission.

[0043] 2. Dopamine D2 receptors are involved in drug-induced relapse after cocaine withdrawal.

[0044] Racloprid is a complete antagonist of D2R, and quinpirole is a complete agonist of D2R. We tested their effects on relapse after low-dose cocaine clearance. Figure 1 e). Using the above model, the first group of experimental mice (Raclopride group) were subcutaneously injected with 0.3 mg / kg Raclopride, and the control group mice (Saline group) were subcutaneously injected with 0.1 ml of physiological saline. Thirty minutes later, 7.5 mg / kg cocaine was injected intraperitoneally, and the test began. The results showed that compared with the control group, the number of effective nostril touches was significantly reduced in mice subcutaneously injected with Raclopride, indicating that Raclopride can inhibit the increase in the number of effective nostril touches and the enhancement of craving after cocaine administration-induced cocaine decay. Figure 1 f:Two-way RMANOVAtest,F groups×session(1,19) =22.944, P<0.001). The second group of mice (Quinpirole group) received an intraperitoneal injection of 0.5 mg / kg Quinpirole, while the control group (Saline group) received an intraperitoneal injection of 0.1 ml saline. Ten minutes later, mice received an intraperitoneal injection of 7.5 mg / kg cocaine and the test began. The results showed that intraperitoneal injection of Quinpirole did not affect the increase in effective nostril touch frequency or drug craving induced by cocaine administration in mice, indicating that Quinpirole did not affect drug-induced relapse after cocaine regression. Figure 1 g: Scheiger-Ray-Hare test, H groups×session(1,20) =1.038, P=0.309). The above results show that blocking the D2R receptor signaling pathway can inhibit cocaine-induced relapse after cocaine elimination induced by cocaine administration, suggesting that the D2R-mediated signaling pathway is involved in cocaine-induced relapse after cocaine elimination induced by low-dose cocaine ignition.

[0045] 3. Downstream G protein-dependent signaling pathways of dopamine D2 receptor are involved in relapse after cocaine withdrawal induced by low-dose cocaine.

[0046] UNC9994, UNC9975, and UNC0006 are derivatives of the third-generation antipsychotic drug aripiprazole, exhibiting D2R G protein antagonism and β-arrestin agonism. We tested the effects of UNC9994, UNC9975, and UNC0006 on cocaine-induced relapse after cocaine administration. One hour before the relapse test, experimental mice (UNC9994, UNC9975, and UNC0006 groups) were intraperitoneally injected with 0.5 mg / kg of UNC9994, UNC9975, or UNC0006, while control mice (Saline group) were intraperitoneally injected with an equal volume of saline. One hour later, mice were intraperitoneally injected with 7.5 mg / kg of cocaine, and the test began. Figure 2 a). Test results showed that, compared with the control group, UNC9994, UNC9975, and UNC0006 all significantly inhibited the number of effective nostril-to-mouth contacts induced by cocaine. Figure 2 bd, UNC9994 group: Scheiger-Ray-Hare test, H groups×session(1,19) =3.909, P=0.048; UNC9975 group: Scheiger-Ray-Hare test, H groups×session(1,19) =10.538, P=0.001; UNC0006 group: Scheiger-Ray-Hare test, H groups×session(1,18) =4.761, P=0.029). This indicates that UNC9994, UNC9975 and UNC0006 can inhibit relapse after cocaine withdrawal induced by low doses of cocaine.

[0047] Next, we investigated the effects of UNC9994, UNC9975, and UNC0006 on spontaneous movement and anxiety levels in mice using open field and elevated cross maze tests. Figure 3 a). Mice in the experimental group were intraperitoneally injected with 0.5 mg / kg UNC9994, UNC9975, or UNC0006, while the control group was injected with an equal volume of saline. One hour later, open field or elevated cross maze tests were performed. The results showed that UNC9994, UNC9975, and UNC0006 did not affect the distance traveled in the peripheral and central regions or the time spent in the central region in the open field test, nor did they affect the time spent in the open and closed arms of the mice in the elevated cross maze test. Figure 3 bc,UNC9994 group: OFT left:t (30)=1.373,p=0.180,Two-tailed Student's t-test,medium:t (30) =0.711, p=0.483, right:t (30) =1.603, p=0.119; EPM left: Two-tailed unpaired t-test, t (30) =-0.543, P=0.591; EPM right: Two-tailed unpaired t-test, t(30)=0.432, P=0.669; Figure 3 de, UNC9975 group: OFT left: Z = -1.922, p = 0.056, Mann-Whitney U test, middle: t (23.431) =1.172, p=0.253, Two-tailed unpaired t-test with Welch's correction, right: t (30) =0.802, p=0.429; EPM left: Mann-Whitney, Z=-0.245, P=0.809; EPM right: Two-tailed unpaired t-test, t(30)=0.021, P=0.983; Figure 3 fg:UNC0006 group:OFT left:t (30) =1.866, p=0.072, in:t (23.932) =1.620, p=0.118, right side: t (25.300) =0.123, p=0.903; EPM left: Two-tailed unpairedt-test with Welch's correction,t (25.59) =0.646, P = 0.524; EPM right: Two-tailed unpaired t-test, t (30) =0.642, P=0.526), ​​indicating that UNC9994, UNC9975 and UNC0006 did not affect spontaneous movement and anxiety levels in mice.

[0048] The above results suggest that inhibiting the downstream G protein signaling pathway of D2R or activating the β-arrestin signaling pathway can inhibit drug-induced post-collapse reconstitution of cocaine. Combined with the results of non-biased agonists of quetiapine D2R, we speculate that D2R may mainly participate in drug-induced post-collapse reconstitution of cocaine through downstream G protein-dependent signaling pathways.

[0049] 4. Inhibition of the downstream β-arrestin signaling pathway of dopamine D2 receptor does not affect relapse after cocaine clearance induced by low-dose cocaine ignition.

[0050] MLS1547 is a D2R G protein agonist and β-arrestin antagonist. Thirty minutes before the relapse test, mice in the experimental group were intraperitoneally injected with MLS1547 (0.5 mg / kg), while the control group received an equal volume of saline intraperitoneally. One hour later, mice were intraperitoneally injected with 7.5 mg / kg cocaine, and the relapse test began. Figure 4 a). Test results showed that, compared with the control group, intraperitoneal injection of MLS1547 did not affect the increase in the number of effective nostril touches induced by cocaine. Figure 4 b: Scheiger-Ray-Hare test, H groups×session(1,18) =0.976, P=0.323).

[0051] Next, the effects of MLS1547 on spontaneous movement and anxiety levels in mice were investigated using open field and elevated cross maze tests. Figure 5 a). The experimental group received an intraperitoneal injection of MLS1547 (0.5 mg / kg), while the control group received an equal volume of physiological saline. Sixty minutes later, either the open field test or the elevated cross maze test was performed. Results showed that MLS1547 did not affect the distance traveled or the time spent in the central region during the open field test, nor did it affect the time spent in the open and closed arms during the elevated cross maze test. Figure 5 bc:OFTleft:t (30) =-0.133, p=0.895, middle: Z=-1.771, p=0.080, right: t (30) =-0.044, p=0.945; EPM left: Two-tailed unpaired t-test, t (30) =0.431, P=0.670; EPM right: Z=-0.151, P=0.897), indicating that MLS1547 does not affect spontaneous movement and anxiety levels in mice.

[0052] The above results suggest that inhibition of the downstream β-arrestin signaling pathway of D2R does not affect drug-induced cocaine reconstitution and does not affect spontaneous movement and anxiety levels in mice.

[0053] 5. Inhibition of the downstream G protein signaling pathway of dopamine D2 receptor can reduce cocaine-induced activation of neurons in the nucleus accumbens.

[0054] To investigate the effect of the D2R G protein signaling pathway on NAc neuron activity, we administered the aforementioned D2R ligand compound after cocaine auto-administration extinction training and observed its effect on low-dose cocaine ignition-induced NAc neuron activation. Figure 6 a). The results showed that low-dose cocaine significantly increased the number of c-Fos-positive neurons in the NAc (a). Figure 6 bc:Two-tailed unpaired t-test withWelch's correction,t (5.168) =9.508, P<0.001). This suggests that low-dose cocaine ignition can activate NAc neurons. Intraperitoneal injection of UNC9994, UNC9975, or UNC0006 (0.5 mg / kg) can significantly inhibit the increase in the number of c-Fos positive neurons in NAc induced by cocaine. Figure 6 df: OnewayANOVAtest,F (3,28) =9.866, P<0.001). Furthermore, MLS1547 did not affect the cocaine-induced increase in the number of c-Fos-positive neurons in the NAc ( ). Figure 6 gi: Mann-Whitney, Z=-1.890, P=0.065).

[0055] The above results indicate that inhibiting the downstream G protein-dependent signaling pathway of dopamine D2 receptor can reduce the activation of neurons in the nucleus accumbens induced by low-dose cocaine ignition.

[0056] The above results suggest that UNC9994, UNC9975, and UNC0006 inhibit drug-ignition-induced cocaine addiction relapse by suppressing the downstream G protein signaling pathway of the dopamine D2 receptor, while MLS1547's inhibition of the downstream β-arrestin signaling pathway of the dopamine D2 receptor does not affect drug-ignition-induced cocaine addiction relapse. Figure 7 ).

Claims

1. The use of dopamine D2 receptor G protein antagonists in the preparation of drugs for treating drug addiction, wherein the drug addiction treatment is aimed at the relapse of drug addiction after the drug addiction has subsided by administering a small dose of drug to ignite drug cravings, thereby generating drug-seeking behavior; dopamine D2 receptor G protein antagonists can inhibit the relapse of drug addiction induced by a small dose of drug after the drug addiction has subsided.

2. The use according to claim 1, characterized in that, The dopamine D2 receptor G protein signaling pathway antagonist is selected from the D2 receptor complete antagonist racloprid, D2 receptor G protein antagonists and β-arrestin agonists UNC9994, UNC9975 and UNC0006.

3. The use according to claim 2, characterized in that, The therapeutic agent is any formulation containing a dopamine D2 receptor G protein antagonist or a pharmaceutically acceptable salt, solvate, or prodrug thereof.

4. The use according to any one of claims 1-4, characterized in that, The therapeutic agent is administered in the form of a sterile injection or infusion.

5. A pharmaceutical composition for the treatment of drug addiction relapse, characterized in that, Contains a dopamine D2 receptor G protein antagonist or a pharmaceutically acceptable salt, solvate or prodrug thereof.

6. The pharmaceutical composition according to claim 4, characterized in that, The dopamine D2 receptor G protein antagonist is selected from the D2 complete antagonist racloprid, D2 G protein antagonists and β-arrestin agonists UNC9994, UNC9975 and UNC0006.

Images