Does nicotine impact tramadol abuse? Insights from neurochemical and neurobehavioral changes in mice

10-dehydrogingerdione amends tramadol-elicited neurotransmitters disturbance and apoptosis in the brain of male rats by repleting non-enzymatic antioxidants

Tramadol is analgesic medication to relief acute and chronic pain, referred to as alternative to opioid drugs however its abuse or overdosage may resulted in neuronal toxicity. This is attributed to severe fluctuations of neurotransmitters pattern along with cerebral inflammation and oxidative damage. Present work was undertaken to illustrate the cytoprotective effect of 10-dehydrogingerdione (10-DHGD) on the brain tissues of experimental rats due to Tramadol intake and its underlying mechanism. 24 male wistar rats were randomized into 4 equal groups. Group (1), received tramadol in a dose level 20 mg/kg intrapertioneal (i.p) daily for 30 days and referred to Tramadol group. Group (2), received both of 10-DHGD (10 mg/kg, orally) one hour before tramadol intake (dose as mentioned before) daily for 30 days. Group (3) received 10-DHGD only (10 mg/kg, orally) and daily for 30 days. Group (4), received no drugs and referred to control group for comparison. Tramadol significantly reduced Norepinephrin (NE), dopamine, serotonin and glutathione (reduced) contents of Cerebral cortex. lipid peroxidation, nuclear factor kappa B (NFkB), inducible nitric oxide synthase (INOS) levels and caspase-3 immunoreactivity showed however significant increase. Of note, 10-DHGD significantly increased neurotransmitters, glutathione contents while Malondialdehyde (MDA), Nitric oxide (NO), NFkB, INOS additionally caspase-3 immunoexpression showed significant decrease i.e counteracted to certain extent tramadol effect. These findings may refer to the cytoprotective potential of 10-DHGD against the neurotoxicity exerted by tramadol intake, most probably mediated via enhancement of endogenous antioxidants system.

Neurological Effects of Combining Low Toxic Dose of Tramadol and Nicotine: An Animal Model Evidence of Endoplasmic Reticulum Stress

Tramadol abuse is a common problem in the Middle East in conjunction with smoking. The current study applied immunohistochemistry, western blot, real-time PCR, and ELISA to test the combination toxicity. Low toxic doses of tramadol induced animal brain cortex inflammation and hippocampus injury. Adding nicotine reverted hippocampus pathological changes without triggering marked brain injury. The expression of CHOP protein with real-time PCR showed mild endoplasmic reticulum stress (ER) in rat's brain. Histological, immunohistochemical, and western blotting analysis of CHOP (CCAAT-enhancer-binding protein homologous protein) and BIP (immunoglobulin heavy chain-binding protein) chaperones demonstrated endoplasmic reticulum stress in the brains of animals. Furthermore, the levels of apoptosis and autophagy markers demonstrated a mild reaction. The blood level of serotonin was high in all study groups, with a marked increase in the combined one. The high serotonin levels in the blood can be critical and associated with a high risk of serious withdrawal and pathological consequences. Serotonin receptor blockers such as olanzapine may increase systemic serotonin levels and need further investigation to utterly pinpoint their roles in managing mood disorders. In conclusion, the combination of tramadol and nicotine is less harmful than expected. However, serious withdrawal effects can occur as a result of high systemic serotonin effects.

Tramadol and Codeine Stacking/Boosting Dose Exposure Induced Neurotoxic Behaviors, Oxidative Stress, Mitochondrial Dysfunction, and Neurotoxic Genes in Adolescent Mice

In spite of the increasing epidemic of pharmaceutical opioids (codeine and tramadol) misuse and abuse among the adolescents, little is known about the neurotoxic consequences of the widespread practice of tramadol and codeine abuse involving increasing multiple doses across days, referred to as stacking and boosting. Hence, in this study, we replicated stacking and boosting doses of tramadol, codeine alone, or in combination on spontaneous motor activity and cognitive function in adolescent mice and adduced a plausible mechanism of possible neurotoxicity. Ninety-six adolescent mice were randomly distributed into 4 groups (n = 24 per group) and treated thrice daily for 9 days with vehicle, tramadol (20, 40, or 80 mg/kg), codeine (40, 80, or 160 mg/kg), or their combinations. Exposure of mice to tramadol induced hyperactivity and stereotypic behavior while codeine exposure caused hypoactivity and nootropic effect but tramadol-codeine cocktail led to marked reduction in spontaneous motor activity and cognitive function. In addition, tramadol, codeine, and their cocktail caused marked induction of nitroso-oxidative stress and inhibition of mitochondrial complex I activity in the prefrontal cortex (PFC) and midbrain (MB). Real-time PCR expression profiling of genes encoding neurotoxicity (RT) showed that tramadol exposure upregulate 57 and downregulate 16 neurotoxic genes, codeine upregulate 45 and downregulate 25 neurotoxic genes while tramadol-codeine cocktail upregulate 52 and downregulate 20 neurotoxic genes in the PFC. Findings from this study demonstrate that the exposure of adolescents mice to multiple and increasing doses of tramadol, codeine, or their cocktail lead to spontaneous motor coordination deficits indicative of neurotoxicity through induction of oxidative stress, inhibition of mitochondrial complex I activity and upregulation of neurotoxicity encoding genes in mice.

Role of cytokine and neurotrophic factors in nicotine addiction in the conditioned place preference paradigm

The mechanisms involved in the maintenance of cigarette smoking and nicotine reward remain unclear. Immune response might play an important role in this context. Nicotine may induce both central and systemic inflammatory responses as well as changes in the regulation of brain-derived neurotrophic factor (BDNF). The conditioned place preference (CPP) is a method used for the evaluation of nicotine-induced reward, reproducing nicotine-seeking behavior in humans. So far, there are no studies investigating the relationship between neuroinflammation and nicotine-induced CPP. This study aimed to evaluate the levels of inflammatory mediators and neurotrophic factors in key areas of the central nervous system (CNS) of mice subject to nicotine-induced CPP. CPP was induced with an intraperitoneal administration of 0.5 mg/kg of nicotine in male Swiss mice, using an unbiased protocol. Control group received vehicle by the same route. The levels of cytokines, chemokines, and neurotrophic factors were measured using Enzyme-Linked Immunosorbent Assay (ELISA) in the brain after CPP test. As expected, nicotine induced place preference behavior. In parallel, we observed increased peripheral levels of IL-6 and IL-10 alongside increased hippocampal levels of NGF but decreased GDNF in mice treated with nicotine compared to controls. In the striatum, nicotine promoted decrease of IL-1ß, IL-10 and GDNF levels, while the levels of all the mediators were similar between groups in the pre-frontal cortex. Our results provide evidence on the role of cytokines and neurotrophic factors in nicotine-induced CPP in mice.

Effects of chronic tramadol administration on cognitive flexibility in mice

RATIONALE

Tramadol is widely used for pain relief especially in seniors. However, long-term use of tramadol has serious adverse effects, including cognitive impairment. Besides its memory effects, already demonstrated in animals, a recent clinical report suggests that tramadol could also affect executive function in seniors. Several studies have hypothesized that the anti-muscarinic properties of tramadol could be responsible for the deleterious effects of tramadol on cognition.

OBJECTIVES

We aimed at investigating the effects of chronic administration of tramadol on cognitive flexibility in adult male mice, as assessed by a visual discrimination reversal task using a touchscreen device. The effects of tramadol were further compared to those of scopolamine, a reference muscarinic antagonist.

RESULTS

We found that, during the early phase of the reversal task, when cognitive flexibility is most in demand, both tramadol-treated mice (20 mg/kg, s.c., twice a day) and scopolamine-treated mice (0.5 mg/kg, s.c., twice a day) needed more correction trials and showed a higher perseveration index than saline-treated mice. Therefore, tramadol affects cognitive flexibility, and its anticholinergic properties could be at least partly involved in these deficits.

CONCLUSIONS

In view of these deleterious cognitive effects of tramadol, physicians should be cautious when prescribing this analgesic, especially in seniors who are more vulnerable to adverse drug events and in which alternative prescription should be preferred whenever possible.

Evaluation of vitamin C protective effect on the cerebrocortical antioxidant defense, histopathological, pro-apoptotic p53 and anti-apoptotic Bcl2 expressions against tramadol neurotoxicity in rats

BACKGROUND

Reported tramadol toxicity emphasizes the necessity to recognize its mechanism of toxicity, particularly to the brain tissue.

AIM

This study aimed to evaluate the protective effect of vitamin C (Vit C) in cerebrocortical toxicity mediated by tramadol in rats using biochemical and histological parameters.

MATERIAL AND METHODS

Forty-eight albino rats were randomly divided into eight groups, (n = 6/group) as follow: the control group received normal saline and vitamin C group received vitamin C (200 mg/kg per oral). Tramadol 50, 100, 150 groups received tramadol in doses of (50, 100 and 150 mg/kg per oral, respectively); Tramadol 50+ Vit C, 100+ Vit C, 150+ Vit C groups received vitamin C (200 mg/kg per oral) plus tramadol in doses of (50, 100 and 150 mg/kg per oral, respectively). Rats had received vitamin C and tramadol daily for 30 days. Blood and brain tissues samples were harvested for biochemical, histopathological, immunohistochemical and electron microscopic examinations.

RESULTS

Tramadol administration leads to a significant elevation of MDA, NO levels and a significant decrease in antioxidants parameters (CAT, SOD and GSH) in the tissues of cerebral cortices in rats which were directly proportional to the dose of tramadol. In histological investigations, tramadol-treated groups showed pyknotic pyramidal cells, multiple red neurons and shrinking red neurons with hallows around it and apoptotic cells were detected. These biochemical abnormalities and histological impairment were ameliorated in groups with tramadol low doses by the co-treatment with vitamin C.

CONCLUSION

vitamin C has antioxidant and anti-apoptotic potentials against tramadol neurotoxicity via suppression of oxidative stress, lipid peroxidation, structural abnormalities, and down-regulation of p53 and overexpression of Bcl2 in the nervous tissues.

Toxicology of tramadol following chronic exposure based on metabolomics of the cerebrum in mice

Tramadol is an opioid used as an analgesic for treating moderate or severe pain. The long-term use of tramadol can induce several adverse effects. The toxicological mechanism of tramadol abuse is unclear. Metabolomics is a very useful method for investigating the toxicology of drug abuse. We investigated the impact of chronic tramadol administration on the cerebrum of mice, focusing on the metabolites after tramadol administration. The mice received 20 or 50 mg/kg body weight tramadol dissolved in physiological saline daily for 5 weeks via oral gavage. Compared with the control group, the low dose tramadol group showed seven potential biomarkers, including gamma-hydroxybutyric acid, succinate semialdehyde, and methylmalonic acid, which were either up- or down-regulated. Compared with the control group, the high dose tramadol group showed ten potential biomarkers, including gamma-hydroxybutyric acid, glutamine, and O-phosphorylethanolamine, which were either up- or down-regulated. The up-regulated gamma-hydroxybutyric acid and the down-regulated succinate semialdehyde revealed that the neurotransmitter system was disrupted after tramadol abuse. Compared with the low dose tramadol group, there were twenty-nine potential biomarkers in the high dose tramadol group, mainly related to the pentose phosphate pathway and glycerophospholipid metabolism. In conclusion, metabolomics in the tramadol abuse group demonstrated that long-term tramadol abuse can result in oxidative damage, inflammation, and disruption of the GABA neurotransmitter system, which will help to elucidate the toxicology of tramadol abuse.

Genotoxicity and repair capability of Mus musculus DNA following the oral exposure to Tramadol

Tramadol is an analgesic and psychoactive drug that acts primarily upon the central nervous system where it alters brain function, resulting in temporary changes in perception, mood, consciousness and behavior. The aim of present study was to analyze the genotoxicity and repair capability of DNA after Tramadol exposure in albino mice (Mus musculus). For this purpose, forty mice were divided equally into four groups as; a control group (without drug) and three treatment groups that were treated with three doses of Tramadol as minimum dose group, Intermediate dose group and maximum dose group, corresponding to 25 mg/kg, 50 mg/kg and 75 mg/kg of body weight respectively. The dose was given orally for 15 days. After 15 days peripheral blood was drawn from half mice of each group and subjected to comet assay. While the remaining half mice were given a recovery period of 15 days and same procedure was used for blood collection and comet assay. Significant difference in various comet parameters was observed among control and exposed groups. Maximum damage was observed at highest concentration 75 mg/kg of Tramadol and minimum damage was observed at dose 25 mg/kg of Tramadol, while results of repaired mice group showed that repair capability of Tramadol was minor and recovery of Tramadol required a lot of time. It can be concluded that Tramadol cause genotoxicity that is dose dependent and has low repair capability.