Levo-tetrahydropalmatine attenuates the acquisition of fentanyl-induced conditioned place preference and the changes in ERK and CREB phosphorylation expression in mice

Oxycodone, an opioid like the others?

The over-prescription of opioid analgesics is a growing problem in the field of addiction, which has reached epidemic-like proportions in North America. Over the past decade, oxycodone has gained attention as the leading opioid responsible for the North America opioid crisis. Oxycodone is the most incriminated drug in the early years of the epidemic of opioid use disorder in USA (roughly 1999-2016). The number of preclinical articles on oxycodone is rapidly increasing. Several publications have already compared oxycodone with other opioids, focusing mainly on their analgesic properties. The aim of this review is to focus on the genomic and epigenetic regulatory features of oxycodone compared with other opioid agonists. Our aim is to initiate a discussion of perceptible differences in the pharmacological response observed with these various opioids, particularly after repeated administration in preclinical models commonly used to study drug dependence potential.

Xylazine potentiates the lethal but not the rewarding effects of fentanyl in mice

BACKGROUND

Fentanyl is commonly laced with xylazine. People who use this combination report heightened effects, but it also increases death risk. Although no medication has been approved to counteract overdoses produced by fentanyl and xylazine, naloxone is frequently used. This paper studies the preclinical rewarding and lethal effects of fentanyl combined with xylazine and the efficacy of yohimbine or naloxone to prevent death.

METHODS

Male Swiss Webster mice were treated with (in mg/kg, i.p.) xylazine (0.3, 1, 3, or 5.6), fentanyl (0.01, 0.3, or 0.1), or 1 xylazine plus 0.01 (non-effective) or 0.1 (effective) fentanyl doses during the conditioned-place preference (CPP) test. In addition, independent groups received (in mg/kg, i.p.): xylazine (31.6, 60, 74.2, or 100), fentanyl (3.1 or 10), or both substances at two doses: 31.6 xylazine + 3.1 fentanyl, or 60 xylazine + 10 fentanyl to analyze lethal effects. We determined whether yohimbine or naloxone (each medication tested at 10 or 30mg/kg) could prevent the lethality produced by fentanyl/xylazine combinations. Female mice were also tested in key experiments.

RESULTS

Xylazine neither induced CPP nor altered fentanyl's rewarding effects. In contrast, lethality was potentiated when fentanyl was combined with xylazine. Naloxone, but not yohimbine, effectively prevented the lethality of the fentanyl/xylazine combinations.

CONCLUSIONS

At the doses tested, xylazine does not increase the rewarding effect of fentanyl on the CPP in male mice but potentiates the risk of fatal overdose in male and female mice. A high naloxone dose prevents death induced by coadministration of fentanyl and xylazine in both sexes.

The composition, pharmacological effects, related mechanisms and drug delivery of alkaloids from Corydalis yanhusuo

Corydalis yanhusuo W. T. Wang, also known as yanhusuo, yuanhu, yanhu and xuanhu, is one of the herb components of many Chinese Traditional Medicine prescriptions such as Jin Ling Zi San and Yuanhu-Zhitong priscription. C. yanhusuo was traditionally used to relieve pain and motivate blood and Qi circulation. Now there has been growing interest in pharmacological effects of alkaloids, the main bioactive components of C. yanhusuo. Eighty-four alkaloids isolated from C. yanhusuo are its important bioactive components and can be characterized into protoberberine alkaloids, aporphine alkaloids, opiate alkaloids and others and proper extraction or co-administration methods modulate their contents and efficacy. Alkaloids from C. yanhusuo have various pharmacological effects on the nervous system, cardiovascular system, cancer and others through multiple molecular mechanisms such as modulating neurotransmitters, ion channels, gut microbiota, HPA axis and signaling pathways and are potential treatments for many diseases. Plenty of novel drug delivery methods such as autologous red blood cells, self-microemulsifying drug delivery systems, nanoparticles and others have also been investigated to better exert the effects of alkaloids from C. yanhusuo. This review summarized the alkaloid components of C. yanhusuo, their pharmacological effects and mechanisms, and methods of drug delivery to lay a foundation for future investigations.

Chronic inflammatory pain promotes place preference for fentanyl in male rats but does not change fentanyl self-administration in male and female rats

The current opioid epidemic is a national health crisis marked by skyrocketing reports of opioid misuse and overdose deaths. Despite the risks involved, prescription opioid analgesics are the most powerful and effective medications for treating pain. There is a clear need to investigate the risk of opioid misuse liability in male and female adults experiencing chronic pain. In the present study, we tested the hypothesis that chronic inflammatory pain would increase fentanyl intake, motivation to acquire fentanyl, and drug seeking in the absence of fentanyl in rats. Fentanyl intake, motivation for fentanyl, and drug seeking were tested under limited and extended access conditions using intravenous fentanyl self-administration. Fos activity in ventral tegmental area (VTA) dopamine neurons following intravenous fentanyl challenge (35 μg/kg) was examined using immunohistochemistry. Finally, we tested whether low-dose fentanyl supports development of conditioned place preference under an inflammatory pain state in rats. Contrary to our hypothesis, fentanyl self-administration and VTA Fos activity were unaffected by inflammatory pain status. During acquisition, males exhibited increased fentanyl intake compared to females. Animals given extended access to fentanyl escalated fentanyl intake over time, while animals given limited access did not. Males given extended access to fentanyl demonstrated a greater increase in fentanyl intake over time compared to females. During the dose-response test, females given limited access to fentanyl demonstrated increased motivation to acquire fentanyl compared to males. Both sexes displayed significant increases in responding for fentanyl as unit fentanyl doses were lowered. Following fentanyl challenge, females exhibited higher numbers of Fos-positive non-dopaminergic VTA neurons compared to males. Using conditioned place preference, we found that chronic inflammatory pain promotes fentanyl preference in males, but not females. These findings suggest that established fentanyl self-administration is resistant to change by inflammatory pain manipulation in both sexes, but chronic inflammatory pain increases the rewarding properties of low-dose fentanyl in males.

Morphine Withdrawal-Induced Hyperalgesia in Models of Acute and Extended Withdrawal Is Attenuated by l-Tetrahydropalmatine

Effective pain control is an underappreciated aspect of managing opioid withdrawal, and its absence presents a significant barrier to successful opioid detoxification. Accordingly, there is an urgent need for effective non-opioid treatments to facilitate opioid detoxification. l-Tetrahydropalmatine (l-THP) possesses powerful analgesic properties and is an active ingredient in botanical formulations used in Vietnam for the treatment of opioid withdrawal syndrome. In this study, rats receiving morphine (15 mg/kg, i.p.) for 5 days per week displayed a progressive increase in pain thresholds during acute 23 h withdrawal as assessed by an automated Von Frey test. A single dose of l-THP (5 or 7.5 mg/kg, p.o.) administered during the 4th and 5th weeks of morphine treatment significantly improves pain tolerance scores. A 7-day course of l-THP treatment in animals experiencing extended withdrawal significantly attenuates hyperalgesia and reduces the number of days to recovery to baseline pain thresholds by 61% when compared to vehicle-treated controls. This indicates that the efficacy of l-THP on pain perception extends beyond its half-life. As a non-opioid treatment for reversing a significant hyperalgesic state during withdrawal, l-THP may be a valuable addition to the currently limited arsenal of opioid detoxification treatments.

High-Throughput Sequencing Reveals That Rotundine Inhibits Colorectal Cancer by Regulating Prognosis-Related Genes

Background: Rotundine is an herbal medicine with anti-cancer effects. However, little is known about the anti-cancer effect of rotundine on colorectal cancer. Therefore, our study aimed to investigate the specific molecular mechanism of rotundine inhibition of colorectal cancer. Methods: MTT and cell scratch assay were performed to investigate the effects of rotundine on the viability, migration, and invasion ability of SW480 cells. Changes in cell apoptosis were analyzed by flow cytometry. DEGs were detected by high-throughput sequencing after the action of rotundine on SW480 cells, and the DEGs were subjected to function enrichment analysis. Bioinformatics analyses were performed to screen out prognosis-related DEGs of COAD. Followed by enrichment analysis of prognosis-related DEGs. Furthermore, prognostic models were constructed, including ROC analysis, risk curve analysis, PCA and t-SNE, Nomo analysis, and Kaplan–Meier prognostic analysis. Results: In this study, we showed that rotundine concentrations of 50 μM, 100 μM, 150 μM, and 200 μM inhibited the proliferation, migration, and invasion of SW480 cells in a time- and concentration-dependent manner. Rotundine does not induce SW480 cell apoptosis. Compared to the control group, high-throughput results showed that there were 385 DEGs in the SW480 group. And DEGs were associated with the Hippo signaling pathway. In addition, 16 of the DEGs were significantly associated with poorer prognosis in COAD, with MEF2B, CCDC187, PSD2, RGS16, PLXDC1, HELB, ASIC3, PLCH2, IGF2BP3, CLHC1, DNHD1, SACS, H1-4, ANKRD36, and ZNF117 being highly expressed in COAD and ARV1 being lowly expressed. Prognosis-related DEGs were mainly enriched in cancer-related pathways and biological functions, such as inositol phosphate metabolism, enterobactin transmembrane transporter activity, and enterobactin transport. Prognostic modeling also showed that these 16 DEGs could be used as predictors of overall survival prognosis in COAD patients. Conclusions: Rotundine inhibits the development and progression of colorectal cancer by regulating the expression of these prognosis-related genes. Our findings could further provide new directions for the treatment of colorectal cancer.

Unique Pharmacology, Brain Dysfunction, and Therapeutic Advancements for Fentanyl Misuse and Abuse

Fentanyl is a fully synthetic opioid with analgesic and anesthetic properties. It has become a primary driver of the deadliest opioid crisis in the United States and elsewhere, consequently imposing devastating social, economic, and health burdens worldwide. However, the neural mechanisms that underlie the behavioral effects of fentanyl and its analogs are largely unknown, and approaches to prevent fentanyl abuse and fentanyl-related overdose deaths are scarce. This review presents the abuse potential and unique pharmacology of fentanyl and elucidates its potential mechanisms of action, including neural circuit dysfunction and neuroinflammation. We discuss recent progress in the development of pharmacological interventions, anti-fentanyl vaccines, anti-fentanyl/heroin conjugate vaccines, and monoclonal antibodies to attenuate fentanyl-seeking and prevent fentanyl-induced respiratory depression. However, translational studies and clinical trials are still lacking. Considering the present opioid crisis, the development of effective pharmacological and immunological strategies to prevent fentanyl abuse and overdose are urgently needed.

A Comprehensive Review on the Chemical Properties, Plant Sources, Pharmacological Activities, Pharmacokinetic and Toxicological Characteristics of Tetrahydropalmatine

Tetrahydropalmatine (THP), a tetrahydroproberine isoquinoline alkaloid, is widely present in some botanical drugs, such as Stephania epigaea H.S. Lo (Menispermaceae; Radix stephaniae epigaeae), Corydalis yanhusuo (Y.H.Chou & Chun C.Hsu) W.T. Wang ex Z.Y. Su and C.Y. Wu (Papaveraceae; Corydalis rhizoma), and Phellodendron chinense C.K.Schneid (Berberidaceae; Phellodendri chinensis cortex). THP has attracted considerable attention because of its diverse pharmacological activities. In this review, the chemical properties, plant sources, pharmacological activities, pharmacokinetic and toxicological characteristics of THP were systematically summarized for the first time. The results indicated that THP mainly existed in Papaveraceae and Menispermaceae families. Its pharmacological activities include anti-addiction, anti-inflammatory, analgesic, neuroprotective, and antitumor effects. Pharmacokinetic studies showed that THP was inadequately absorbed in the intestine and had rapid clearance and low bioavailability in vivo, as well as self-microemulsifying drug delivery systems, which could increase the absorption level and absorption rate of THP and improve its bioavailability. In addition, THP may have potential cardiac and neurological toxicity, but toxicity studies of THP are limited, especially its long-duration and acute toxicity tests. In summary, THP, as a natural alkaloid, has application prospects and potential development value, which is promising to be a novel drug for the treatment of pain, inflammation, and other related diseases. Further research on its potential target, molecular mechanism, toxicity, and oral utilization should need to be strengthened in the future.