Electroacupuncture reverses ethanol-induced locomotor sensitization and subsequent pERK expression in mice

Inhibition of FGF Receptor-1 Suppresses Alcohol Consumption: Role of PI3 Kinase Signaling in Dorsomedial Striatum

Excessive alcohol intake leads to mesostriatal neuroadaptations, and to addiction phenotypes. We recently found in rodents that alcohol increases fibroblast growth factor 2 (FGF2) expression in the dorsomedial striatum (DMS), which promotes alcohol consumption. Here, we show that systemic or intra-DMS blockade of the FGF2 receptor, FGF receptor-1 (FGFR1), suppresses alcohol consumption, and that the effects of FGF2-FGFR1 on alcohol drinking are mediated via the phosphoinositide 3 kinase (PI3K) signaling pathway. Specifically, we found that sub-chronic alcohol treatment (7 d × 2.5 g/kg, i.p.) increased Fgfr1 mRNA expression in the dorsal hippocampus and dorsal striatum. However, prolonged and excessive voluntary alcohol consumption in a two-bottle choice procedure increased Fgfr1 expression selectively in DMS. Importantly, systemic administration of the FGFR1 inhibitor PD173074 to mice, as well as its infusion into the DMS of rats, decreased alcohol consumption and preference, with no effects on natural reward consumption. Finally, inhibition of the PI3K, but not of the mitogen-activated protein kinase (MAPK) signaling pathway, blocked the effects of FGF2 on alcohol intake and preference. Our results suggest that activation of FGFR1 by FGF2 in the DMS leads to activation of the PI3K signaling pathway, which promotes excessive alcohol consumption, and that inhibition of FGFR1 may provide a novel therapeutic target for alcohol use disorder.SIGNIFICANCE STATEMENT Long-term alcohol consumption causes neuroadaptations in the mesostriatal reward system, leading to addiction-related behaviors. We recently showed that alcohol upregulates the expression of fibroblast growth factor 2 (FGF2) in dorsomedial striatum (DMS) or rats and mice, and in turn, FGF2 increases alcohol consumption. Here, we show that long-term alcohol intake also increases the expression of the FGF2 receptor, FGFR1 in the DMS. Importantly, inhibition of FGFR1 activity by a selective receptor antagonist reduces alcohol drinking, when given systemically or directly into the DMS. We further show that the effects of FGF2-FGFR1 on alcohol drinking are mediated via activation of the PI3K intracellular signaling pathway, providing an insight on the mechanism for this effect.

Acupuncture therapy for drug addiction

Acupuncture therapy has been used to treat substance abuse. This study aims to review experimental studies examining the effects of acupuncture on addiction. Research and review articles on acupuncture treatment of substance abuse published between January 2000 and September 2014 were searched using the databases ISI Web of Science Core Collection and EBSCO’s MEDLINE Complete. Clinical trial studies on the efficacy of acupuncture therapy for substance abuse were classified according to substance (cocaine, opioid, nicotine, and alcohol), and their treatment protocols, assessments, and findings were examined. A total of 119 studies were identified, of which 85 research articles addressed the efficacy of acupuncture for treating addiction. There were substantial variations in study protocols, particularly regarding treatment duration, frequency of electroacupuncture, duration of stimulation, and choice of acupoints. Contradictory results, intergroup differences, variation in sample sizes, and acupuncture placebo effects made it difficult to evaluate acupuncture effectiveness in drug addiction treatment. This review also identified a lack of rigorous study design, such as control of confounding variables by incorporating sham controls, sufficient sample sizes, reliable assessments, and adequately replicated experiments.

Temporal and behavioral variability in cannabinoid receptor expression in outbred mice submitted to ethanol-induced locomotor sensitization paradigm

BACKGROUND

There is a close relationship between the endocannabinoid system and alcoholism. This study investigated possible differential expression of cannabinoid receptors CB1 (CB1R) and CB2 (CB2R) in an outbred mice strain displaying behavioral variability to ethanol (EtOH)-induced locomotor sensitization.

METHODS

Male adult Swiss mice treated chronically with EtOH (2 g/kg, i.p., daily for 21 days) were classified as "EtOH_High" or "EtOH_Low" according to their locomotor activity after the 21st EtOH injection. A control group was similarly injected with saline. Temporal analysis of CB1R and CB2R immunoreactivity was performed in 3 different occasions: (i) at the end of chronic EtOH treatment, (ii) on the fifth day of EtOH withdrawal, and (iii) after EtOH challenge.

RESULTS

Overall, no differences were seen between experimental groups regarding the CB1R at the end of acquisition. However, there were decreases in CB2R in the prefrontal cortex and the hippocampus in EtOH_Low mice. On the fifth day of withdrawal, only EtOH_High mice presented increase in CB1R. Nonetheless, CB2R up-regulation was observed in both EtOH_High and EtOH_Low mice. EtOH challenge counteracted CB1R and CBR2 up-regulation, mainly in the EtOH_High, in structures related to emotionality, such as prefrontal cortex, ventral tegmental area, amygdala, striatum, and hippocampus.

CONCLUSIONS

There are different patterns of cannabinoid receptor expression during locomotor sensitization paradigm, at both temporal and behavioral perspectives. We hypothesize that CB2R down-regulation might be related to resilience to develop locomotor sensitization, while CB1R up-regulation relates to withdrawal aspects in sensitized mice.

Electroacupuncture reduces cocaine-induced seizures and mortality in mice

The aims of this study were to characterize the protective profile of electroacupuncture (EA) on cocaine-induced seizures and mortality in mice. Mice were treated with EA (2 Hz, 50 Hz, and 100 Hz), or they underwent needle insertion without anesthesia at the Dazhui (GV14) and Baihui (GV20) acupoints before cocaine administration. EA at 50 Hz applied to GV14 and GV20 significantly reduced the seizure severity induced by a single dose of cocaine (75 mg/kg; i.p.). Furthermore, needle insertion into GV14 and GV20 and EA at 2 Hz and 50 Hz at both acupoints significantly reduced the mortality rate induced by a single lethal dose of cocaine (125 mg/kg; i.p.). In the sham control group, EA at 50 Hz applied to bilateral Tianzong (SI11) acupoints had no protective effects against cocaine. In addition, EA at 50 Hz applied to GV14 and GV20 failed to reduce the incidence of seizures and mortality induced by the local anesthetic procaine. In an immunohistochemistry study, EA (50 Hz) pretreatment at GV14 and GV20 decreased cocaine (75 mg/kg; i.p.)-induced c-Fos expression in the paraventricular thalamus. While the dopamine D₃ receptor antagonist, SB-277011-A (30 mg/kg; s.c), did not by itself affect cocaine-induced seizure severity, it prevented the effects of EA on cocaine-induced seizures. These results suggest that EA alleviates cocaine-induced seizures and mortality and that the dopamine D₃ receptor is involved, at least in part, in the anticonvulsant effects of EA in mice.

Blockade of ethanol-induced behavioral sensitization by sodium butyrate: descriptive analysis of gene regulations in the striatum

BACKGROUND

Behavioral sensitization induced by repeated ethanol (EtOH) exposure may play a critical role in the development of alcohol dependence. Because recent data demonstrate that histone deacetylase inhibitor (HDACi) may be of interest in the treatment of addiction, we explored the effect of the HDACi sodium butyrate (NaB) on EtOH-induced behavioral sensitization (EIBS) in DBA/2J mice. We also investigated gene regulations in the striatum of sensitized mice using epigenetic- and signal transduction-related PCR arrays.

METHODS

Mice were injected with saline or EtOH (0.5 to 2.5 g/kg) once a day for 10 days. Mice received NaB (200 to 600 mg/kg) 30 minutes before each injection (prevention protocol) or once daily between days 11 and 16 (reversal protocol). At day 17, brains were removed 30 minutes after a saline or EtOH challenge to assess gene and proteins levels.

RESULTS

Only the intermediate EtOH doses (1.0 and 2.0 g/kg) were effective in inducing EIBS, and both doses were associated with specific gene regulations in the striatum. The induction of sensitization by 1.0 g/kg (but not 2.0 g/kg) EtOH was dose-dependently prevented or reversed by NaB. Among the 168 studied genes, EIBS blockade was associated with specific gene regulations (bcl-2, bdnf, hdac4, pak1, penk, tacr1, vip…) and changes in brain-derived neurotrophic factor in both striatum and prefrontal cortex.

CONCLUSIONS

These results indicate that EIBS is associated with specific gene regulations in the striatum depending on the EtOH dose and that NaB can be useful in blocking some long-lasting neuro-adaptations to repeated EtOH administrations.