Background Alcohol dependence is a complex psychiatric disorder demanding development of novel pharmacotherapies. Since the cyclic AMP (cAMP) signaling cascade has been implicated in mediating behavioral responses to alcohol, key components in this cascade may serve as potential treatment targets. Phosphodiesterase 4 (PDE4), an enzyme that specifically catalyzes the hydrolysis of cAMP, represents as a key point in regulating intracellular cAMP levels. Thus, it was of interest to determine whether PDE4 was involved in the regulation of alcohol use and abuse. Methods Male Fawn-Hooded (FH/Wjd) rats were tested for 5% (v/v) ethanol and 10% (w/v) sucrose operant oral self-administration following treatment with the selective PDE4 inhibitor rolipram (0.0125, 0.025, or 0.05 mg/kg, s.c.); rolipram at higher doses (0.05, 0.1, and 0.2 mg/kg, s.c.) was tested to determine its impact on the intake of ethanol, sucrose, or water using the two-bottle choice drinking paradigm. Subsequent open-field testing was performed to evaluate the influence of higher doses of rolipram on locomotor activity. Results Acute administration of rolipram dose-dependently reduced operant self-administration of 5% ethanol, but had no effect on 10% sucrose responding. Time-course assessment revealed significant decreases in ethanol consumption after rolipram (0.1, 0.2 mg/kg) treatment in continuous- and intermittent-access to ethanol at 5% or 10%, respectively. Moreover, chronic rolipram treatment time-dependently decreased 5% ethanol consumption and preference during treatment days and after the termination of rolipram administration. Rolipram at the highest doses (0.1 and 0.2 mg/kg) did decrease locomotor activity, but the effect lasted only 10 and 20 min, respectively, which did not likely alter long-term ethanol drinking. Conclusions These results suggest that PDE4 plays a role in alcohol seeking and consumption behavior. Drugs interfering with PDE4 may be a potential pharmacotherapy for alcohol dependence.

Purpose: Intrathecal morphine infusion therapy via a percutaneous port (IMITPP) has been used widely for its relatively low initial cost. However, there is scarce knowledge about IMITPP. In this study, we sought to evaluate efficacy, complications, and the interval required to achieve the cost equivalence of IMITPP in patients with refractory cancer pain in China. Patients and Methods: A retrospective chart review was conducted on cancer patients who had received IMITPP at our hospital between April 2017 and April 2019. Data from the numeric pain rating scale and Karnofsky performance scores, and complications and costs related to IMITPP were collected from medical records. Daily analgesic costs before and after IMITPP were calculated based on the doses of opioids on admission and at discharge, respectively. The doses of systemic opioids before IMITPP were stratified into very high doses [VHD, oral morphine equivalent dose (OMED) >599 mg/day], high doses (HD, 300 mg/day ≤ OMED ≤ 599 mg/day), and regular doses (RD, OMED < 300 mg/day). Results: Intrathecal morphine infusion therapy via a percutaneous port provided significant pain relief, but impaired activities of daily living in patients with refractory cancer pain. The commonly reported complications included nausea/vomiting and urinary retention, most of which were managed with symptomatic therapies. The median interval required to achieve cost equivalence was 11.44 months. The median intervals of VHD group and HD group were significantly shorter than that of RD group. Conclusion: Intrathecal morphine infusion therapy via a percutaneous port provided effective cancer pain management without causing serious complications. Patients with higher doses of systemic opioids would economically benefit from IMITPP in a shorter time.

No abstract

New protein synthesis has been implicated as necessary for long-lasting changes in neuronal function. Behavioural sensitization to a single exposure to addictive drugs is a form of neuroplasticity, but little is known about the importance of new protein synthesis in the underlying mechanism. This study was designed to investigate the effects of the transcription inhibitor actinomycin D (AD) and the protein synthesis inhibitor cycloheximide (CHX) on induction of behavioural sensitization to a single morphine exposure in mice. In combination with behavioural experiments, changes in gene and protein expression in the mouse nucleus accumbens (NAc) were analysed by RT-PCR array and Western blot respectively. Behavioural sensitization was evident in mice pretreated only once with morphine at the doses of 20 and 40 mg/kg, but not 5 and 10 mg/kg. Mice pretreated with morphine (20 mg/kg) and challenged with a lower dose (5 mg/kg) after a period of 4-21 d washout showed sensitized locomotion. At the doses that did not affect locomotion in mice, AD or CHX significantly suppressed hyperactivity induced by acute treatment, but not challenge with morphine, and blocked induction of behavioural sensitization to a single morphine exposure in a dose-related manner. The results from RT-PCR array and Western blot indicated that the changes of Hsp70 expression in the NAc of mice were associated with behavioural sensitization induced by a single morphine exposure. Together, these findings suggest that induction of behavioural sensitization to a single morphine exposure requires new protein synthesis, potentially involving Hsp70 expression in the NAc of mice.

No abstract

De-novo protein synthesis is required in the development of behavioural sensitization. A prior screening test from our laboratory has implicated heat shock protein 70 (Hsp70) as one of the proteins required in this behavioural plasticity. Thus, this study was designed to extend our understanding of the role of Hsp70 in the development of behavioural sensitization induced by a single morphine exposure in mice. First, by employing transcription inhibitor actinomycin D (AD) and protein synthesis inhibitor cycloheximide (CHX), we identified a protein synthesis-dependent labile phase (within 4 h after the first morphine injection) in the development of behavioural sensitization to a single morphine exposure. Second, Hsp70 protein expression in the nucleus accumbens correlated positively with locomotor responses of sensitized mice and, more importantly, the expression of Hsp70 increased within 1 h after the first morphine injection. Third, AD and CHX both prevented expression of Hsp70 and disrupted the development of the single morphine induced behavioural sensitization, which further implied Hsp70 was highly associated with behavioural sensitization. Finally, the selective Hsp70 inhibitor pifithrin-μ (PES) i.c.v. injected in mice prevented the development of behavioural sensitization and, critically, this inhibitory effect occurred only when PES was given within 1 h after the first morphine injection, which was within the labile phase of the development period. Taken together, we draw the conclusion that Hsp70 is crucially involved in the labile phase of the development of behavioural sensitization induced by a single morphine exposure, probably functioning as a molecular chaperone.

Drug addiction is a major public health issue, yet the underlying adaptation of neural networks by drugs of abuse is not fully understood. We have previously linked chaperone heat shock protein 70 (Hsp70) to drug-induced adaptations. Focusing on the NAc core and shell, the present study aims to provide further findings for our understanding of the relation between behavioural sensitization to morphine and Hsp70 at transcriptional and functional levels in rats. Firstly, we delineated the characteristics of behavioural sensitization induced by a single morphine exposure (1-10 mg/kg, s.c.). Secondly, Hsp70 protein expression in the NAc core was time- and dose-relatedly induced during the development of behavioural sensitization to a single morphine exposure in rats, and Pearson analysis indicated a positive correlation between behavioural sensitization and Hsp70 expression in NAc core. Thirdly, at the transcriptional level, intra-NAc core injection of the specific heat shock factor-I (HSF-I) inhibitor N-Formyl-3,4-methylenedioxy-benzylidine-γ-butyrolactam (KNK437) suppressed Hsp70 expression and the development of behavioural sensitization, while the HSF-I specific inducer geranylgeranylacetone (GGA) promoted both of them. Interestingly, intra-NAc shell injection of KNK437 or GGA did not affect the development of behavioural sensitization. Finally, both the functional inhibition of Hsp70 ATPase activity by methylene blue (MB), and the antagonism of Hsp70 substrate binding site (SBD) activity by pifithrin-μ (PES) impaired the development of behavioural sensitization when they were microinjected into the NAc core. Taken together, the critical involvement of chaperone Hsp70 in behavioural sensitization to morphine identifies a biological target for long-lasting adaptations with relevance to addiction.

Ginsenoside Re, an active ingredient in Panax ginseng, is widely used as a therapeutic and nutriment. The intestinal microbiota plays crucial roles in modulating the pharmacokinetics and pharmacological actions of ginsenoside Re. The aim of this study was to explore the relationship between bacterial community variety and the metabolic profiles of ginsenoside Re. We developed two models with intestinal dysbacteriosis: a pseudo-germ-free model induced by a nonabsorbable antimicrobial mixture (ATM), and Qi-deficiency model established via over-fatigue and acute cold stress (OACS). First, the bacterial community structures in control, ATM and OACS rats were compared via 16S ribosomal RNA amplicon sequencing. Then, the gut microbial metabolism of ginsenoside Re was assessed qualitatively and quantitatively in the three groups by UPLC-Q-TOF/MS and HPLC-TQ-MS, respectively. Ten metabolites of ginsenoside Re were detected and tentatively identified, three of which were novel. Moreover, owing to significant differences in bacterial communities, deglycosylated products, as the main metabolites of ginsenoside Re, were produced at lower levels in ATM and OACS models. Importantly, the levels of these deglycosylated metabolites correlated with alterations in Prevotella, Lactobacillus and Bacteroides populations, as well as glycosidase activities. Collectively, biotransformation of ginsenoside Re is potentially influenced by regulation of the composition of intestinal microbiota and glycosidase activities.