The influence of a new derivate of kisspeptin-10 - Kissorphin (KSO) on the rewarding effects of morphine in the conditioned place preference (CPP) test in male rats

Susceptibility to arecoline in male C57BL/6J mice correlates with age factor

Epidemiological investigations and clinical studies have confirmed that human chewing of betel nut is an addictive behavior, and the proportion of teenagers chewing betel nut is increasing. Previous studies have shown that adolescence shows higher sensitivity to many addictive substances compared with adulthood, and that adult susceptibility to addictive substances is usually changed after exposure to addictive substances during adolescence. However, there are no reports of age-related animal experiments on betel nut or dependence to its active ingredients. Therefore, the two-bottle choice (TBC) (experiment 1 and 2) and conditioned place preference (CPP) (experiment 3 and 4) models with mice were used in this study to explore age-related differences in intake and preference of arecoline, the alkaloid in betel nut with highest content, and to explore the effect of arecoline exposure during adolescence on the re-exposure of arecoline in adulthood in mice. The results of experiment 1 showed that the intake of 80μg/ml arecoline in adolescent mice was significantly higher than that in adult mice. However, there was no significant difference between adult and adolescent mice in preference for arecoline at any tested concentration (5-80μg/ml), which may be due to the significantly higher intake of total fluid in adolescent mice compared to adult mice. The preference of arecoline in adolescent mice peaked at 20μg/ml, and in adult mice peaked at 40μg/ml. The results of experiment 2 showed that oral arecoline (5-80μg/ml) in mice during adolescence caused a significant increase in the intake (days 3-16) and preference (days 5-8) for 40μg/ml arecoline in adulthood. The results of experiment 3 showed that the doses of 0.03 or 0.1mg/kg of arecoline produced the highest CPP response in adolescent or adult mice, respectively. The results of experiment 4 showed that mice exposed to arecoline in adolescence had significantly increased the CPP scores induced by arecoline in adulthood compared to mice that were not exposed. These data suggested that adolescent mice were more sensitive to arecoline, and exposure of mice to arecoline during adolescence increased the susceptibility to arecoline in adulthood.

Selective Modulation of Hippocampal Theta Oscillations in Response to Morphine versus Natural Reward

Despite the overlapping neural circuits underlying natural and drug rewards, several studies have suggested different behavioral and neurochemical mechanisms in response to drug vs. natural rewards. The strong link between hippocampal theta oscillations (4-12 Hz) and reward-associated learning and memory has raised the hypothesis that this rhythm in hippocampal CA1 might be differently modulated by drug- and natural-conditioned place preference (CPP). Time-frequency analysis of recorded local field potentials (LFPs) from the CA1 of freely moving male rats previously exposed to a natural (in this case, food), drug (in this case, morphine), or saline (control) reward cue in the CPP paradigm showed that the hippocampal CA1 theta activity represents a different pattern for entrance to the rewarded compared to unrewarded compartment during the post-test session of morphine- and natural-CPP. Comparing LFP activity in the CA1 between the saline and morphine/natural groups showed that the maximum theta power occurred before entering the unrewarded compartment and after the entrance to the rewarded compartment in morphine and natural groups, respectively. In conclusion, our findings suggest that drug and natural rewards could differently affect the theta dynamic in the hippocampal CA1 region during reward-associated learning and contextual cueing in the CPP paradigm.

Ovarian cancer and KiSS-1 gene expression: A consideration of the use of Kisspeptin plus Kisspeptin aptamers in diagnostics and therapy

Gynaecological cancers continue to present a significant health burden upon the health of the global female population. This deficit is most prominent with ovarian cancer which possesses the lowest survival rate compared to all other cancers occurring within this anatomical region, with an annual UK-mortality of 7,300. The poor tolerability and selectively of the treatment options that are currently available is likely to have contributed to this high mortality rate thus, demonstrating the need for the development of enhanced therapeutic approaches. Aptamer technology would involve the engineering of specifically sequenced oligonucleotide chains, which bind to macromolecular targets with a high degree of affinity and selectively. Recent in-vitro studies conducted upon the clinical utility of this technique have supported its superiority in targeting individual therapeutic drug targets compared to various other targeting moieties currently within therapeutic use such as, monoclonal antibodies. For this reason, the employment of this technique is likely to be favourable in reducing the incidence of non-specific, chemotherapy-associated adverse effects. Kisspeptin is a naturally expressed polypeptide with an established role in the development of the reproductive system and other proposed roles in influencing the ability of ovarian cancer growths to exhibit the metastasis hallmark. This distinctive feature would indicate the potential for the manipulation of this pathway through the application of aptamer structures in developing a novel prophylactic strategy and improve the long-term outcome for ovarian cancer patients.

The IntelliCage System: A Review of Its Utility as a Novel Behavioral Platform for a Rodent Model of Substance Use Disorder

The use of animal models for substance use disorder (SUD) has made an important contribution in the investigation of the behavioral and molecular mechanisms underlying substance abuse and addiction. Here, we review a novel and comprehensive behavioral platform to characterize addiction-like traits in rodents using a fully automated learning system, the IntelliCage. This system simultaneously captures the basic behavioral navigation, reward preference, and aversion, as well as the multi-dimensional complex behaviors and cognitive functions of group-housed rodents. It can reliably capture and track locomotor and cognitive pattern alterations associated with the development of substance addiction. Thus, the IntelliCage learning system offers a potentially efficient, flexible, and sensitive tool for the high-throughput screening of the rodent SUD model.

Crosstalk between Opioid and Anti-Opioid Systems: An Overview and Its Possible Therapeutic Significance

Opioid peptides and receptors are broadly expressed throughout peripheral and central nervous systems and have been the subject of intense long-term investigations. Such studies indicate that some endogenous neuropeptides, called anti-opioids, participate in a homeostatic system that tends to reduce the effects of endogenous and exogenous opioids. Anti-opioid properties have been attributed to various peptides, including melanocyte inhibiting factor (MIF)-related peptides, cholecystokinin (CCK), nociceptin/orphanin FQ (N/OFQ), and neuropeptide FF (NPFF). These peptides counteract some of the acute effects of opioids, and therefore, they are involved in the development of opioid tolerance and addiction. In this work, the anti-opioid profile of endogenous peptides was described, mainly taking into account their inhibitory influence on opioid-induced effects. However, the anti-opioid peptides demonstrated complex properties and could show opioid-like as well as anti-opioid effects. The aim of this review is to detail the phenomenon of crosstalk taking place between opioid and anti-opioid systems at the in vivo pharmacological level and to propose a cellular and molecular basis for these interactions. A better knowledge of these mechanisms has potential therapeutic interest for the control of opioid functions, notably for alleviating pain and/or for the treatment of opioid abuse.

KISS1 in metastatic cancer research and treatment: potential and paradoxes

The significance of KISS1 goes beyond its original discovery as a metastasis suppressor. Its function as a neuropeptide involved in diverse physiologic processes is more well studied. Enthusiasm regarding KISS1 has cumulated in clinical trials in multiple fields related to reproduction and metabolism. But its cancer therapeutic space is unsettled. This review focuses on collating data from cancer and non-cancer fields in order to understand shared and disparate signaling that might inform clinical development in the cancer therapeutic and biomarker space. Research has focused on amino acid residues 68-121 (kisspeptin 54), binding to the KISS1 receptor and cellular responses. Evidence and counterevidence regarding this canonical pathway require closer look at the covariates so that the incredible potential of KISS1 can be realized.