Pemirolast reduces cisplatin-induced kaolin intake in rats

Ondansetron attenuates cisplatin-induced behavioral and cognitive impairment through downregulation of NOD-like receptor inflammasome pathway

Cisplatin is an effective and commonly used chemotherapeutic drug; however, its use is accompanied by several adverse effects, including chemobrain. Ondansetron is a 5-HT3 antagonist, commonly used in prophylactic against chemotherapy-induced nausea and vomiting. Moreover, it has been identified as a novel neuroprotective agent in different animal models. However, its protective role against chemotherapy-induced chemobrain has not been investigated. The current study was the first study that explored the potential neuroprotective effect of ondansetron against cisplatin-induced chemobrain in rats. Cisplatin (5 mg/Kg) was injected intraperitoneally, once weekly, for 4 weeks with the daily administration of ondansetron (0.5 and 1 mg/Kg). Compared to the cisplatin-treated group, ondansetron administration showed a significant decrease in the latency time and a significant increase in ambulation, rearing, and grooming frequency in the open field test (OFT). Moreover, a significant improvement in the latency time in the rotarod and passive avoidance tests, following ondansetron administration. In addition, ondansetron treatment increased the percentage of alternation in the Y-maze test. Also, ondansetron showed a remarkable enhancement in the biochemical parameters in the hippocampus. It increased the acetylcholine (Ach) level and decreased the level of the acetylcholine esterase enzyme (AchE). Ondansetron significantly decreased interleukin-1β (Il-1β), tumor necrosis factor-alpha (TNF-α), toll-like receptor-4 (TLR-4), NOD-like receptor-3 (NLRP3) inflammasome as well as caspase-1 and caspase-3 levels. Furthermore, ondansetron significantly decreased the levels of copper transporter-1(CTR1) expression in the hippocampus. Collectively, these findings suggest that ondansetron may exhibit a neuroprotective and therapeutic activity against cisplatin-induced chemobrain.

Substance P Increases the Excitability of Dorsal Motor Nucleus of the Vagus Nerve via Inhibition of Potassium Channels

Increases in the substance P (SP) concentration in the medial portion of the dorsal motor nucleus of the vagus nerve (mDMV) in the brainstem are closely associated with chemotherapy induced nausea and vomiting (CINV). However, the underlying cellular and molecular mechanisms of action are not well understood. In this study, we investigated the effects of SP on mDMV neurons using whole-cell patch-clamp recordings from rat brainstem slices. Application of different concentrations of SP induced tonic and phasic responses. Submicromolar concentrations of induced an inward shift of the holding current by increasing membrane input resistance. The response was mimicked by acidification of the extracellular solution and inhibited by a neurokinin type 1 receptor antagonist. These responses have equilibrium potentials close to the K⁺ equilibrium potential. In addition, a TWIK-related acid-sensitive K⁺ channel 3 (TASK-3) inhibitor, PK-THPP, induced responses similar to those produced by submicromolar SP concentrations. Micromolar concentrations of SP facilitated γ-aminobutyric acid (GABA) release but diminished glutamate release; these changes were blocked by a GABA_B receptor antagonist and a neurokinin type 3 receptor antagonist, respectively. In current-clamp recordings, submicromolar SP concentrations increased neuronal excitability by depolarizing membrane potentials. However, neither the increase in SP concentration to the micromolar range nor the addition of GABA_A and ionotropic glutamate receptor antagonists affected neuronal excitability. Thus, SP increases the excitability of mDMV neurons by inhibiting K⁺ conductance.

A novel effect of Aprepitant: Protection for cisplatin-induced nephrotoxicity and hepatotoxicity

Cisplatin is widely used chemotherapeutic drug and have some serious side effects as tissue toxicity and nausea and vomiting. Aprepitant is used in clinic as an anti-emetic drug for cisplatin treated patient to prevent nausea and vomiting. We aimed to investigate the protective effects of Aprepitant on cisplatin-induced nephrotoxicity and hepatotoxicity. In total 42 male rats were separated into six groups (n = 7). A single dose of cisplatin (10 mg/kg i.p.) was administered to induce toxicity on first day. Different doses of Aprepitant (5, 10 and 20 mg/kg, p.o.) were given to treatment groups during 3 days. After the experimental procedures serum enzymes (ALT, AST, ALP, BUN and Creatinin), kidney and liver oxidative parameters (SOD, GSH and MDA), inflammatory cytokines (TNF-α and NF-κB) and Cyp2e1 expressions analyzed. Histopathological investigations also performed for all groups. Cisplatin caused tissue toxicity in both kidney and liver. Serum enzymes, tissue cytokines and oxidative stress were increased after the Cis treatment. Aprepitant treatment normalized all parameters compared to cisplatin treated group. Cisplatin significantly increased the Cyp2e1 expression in the kidney while significantly decreased in the liver compared to Healthy group. Histopathologically, it was shown that cisplatin causes a lot of abnormal structures as inflammatory infiltration and necrosis on the liver and kidney. Similar the biochemical and molecular results, aprepitant showed positive effects on tissue pathological parameters. With its main anti-emetic effect, Aprepitant treatment may be an effective option for cancer patients if they have additional injury as nephrotoxicity and hepatotoxicity due to cisplatin.

Synthesis, Characterization and Biocompatibility of N-palmitoyl L-alanine-based Organogels as Sustained Implants of Granisetron and Evaluation of thier Antiemetic Effect

PURPOSE

To assess the gelation power of N-palmitoyl L-alanine derivatives in injectable oils and to use the best chosen organogel as parenteral implant of granisetron for the treatment of emesis.

METHODS

Twelve N-palmitoyl L-alanine derived organogels were developed and evaluated in terms of morphology, thermal properties and in vivo performance. The ability of the selected formula to form in situ gel upon subcutaneous injection in rats and its biocompatibility were monitored over 2 weeks by histopathological examination of the injection site.

RESULTS

The acid derivative (N-palmitoyl L-alanine; PA) was superior to ester derivatives. The chosen formula (PA/safflower oil 10% w/v) was successful in forming an in situ gel of granisetron when subcutaneously injected in rats, lasting for 2 weeks and proved to be biocompatible by histopathological examination. Moreover, it exerted an extended antiemetic activity by decreasing the cisplatin-induced pica for a duration of 96 h and reduced preprotachykinin A mRNA expression and Substance P level for up to 4 days (gastric tissue) or 5 days (medulla oblongata) in rats.

CONCLUSION

Granisetron organogel could be considered as a safe, sustained-release and supportive anticancer treatment in both acute and chronic emesis as well as an accompanying treatment with chemotherapeutics in cancer cases.

One-pot synthesis of novel 1-(1H-tetrazol-5-yl)-1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine derivatives via an Ugi-azide 4CR process

A facile one-pot method has been developed for the synthesis of novel pyrrolo[2,1-a]pyrazine scaffolds. A variety of 1-(1H-tetrazol-5-yl)-1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine derivatives were obtained in moderate to high yields in methanol using a one-pot four-component condensation of 1-(2-bromoethyl)-1H-pyrrole-2-carbaldehyde, amine, isocyanide and sodium azide at room temperature. These reactions presumably proceed via a domino imine formation, intramolecular annulation and Ugi-azide reaction. Unambiguous assignment of the molecular structures was carried out by single-crystal X-ray diffraction.

Ghrelin fibers from lateral hypothalamus project to nucleus tractus solitaries and are involved in gastric motility regulation in cisplatin-treated rats

Ghrelin can alleviate cancer chemotherapy-induced dyspepsia in rodents, though the neural mechanisms involved are not known. Therefore, ghrelin projections from the lateral hypothalamus (LH) and its involvement in the regulation of gastric motility in cisplatin-treated rats were investigated with a multi-disciplined approach. Retrograde tracing combined with fluoro-immunohistochemical staining were used to investigate ghrelin fiber projections arising from LH and projecting to nucleus tractus solitaries (NTS). Results revealed that ghrelin fibers originating in LH project to NTS. Expression of ghrelin and its receptor growth hormone secretagogue receptor (GHS-R1a) in LH and NTS were detected by Western Blot. 2days after cisplatin dosing, expression of ghrelin in LH decreased while GHS-R1a in both LH and NTS increased. In electrophysiological experiments, the effects of N-methyl-d-aspartate (NMDA) microinjection in LH on neuronal discharge of gastric distension-responsive neurons in NTS and gastric motility were assessed. NMDA in LH excited most of ghrelin-responsive gastric distension (GD)-sensitive neurons in NTS and promoted gastric motility. This effect was partially blocked by ghrelin antibody in NTS. Furthermore, the excitatory effects of NMDA in cisplatin-treated rats were weaker than those in saline-treated rats. Behaviorally, cisplatin induced a significant increase of kaolin consumption and decrease of food intake. These studies reveal a decreased expression of ghrelin in LH and up-regulation of GHS-R1a in LH and NTS, which are involved in the regulation of GD neuronal discharge in NTS and gastric motility.

Cannabinoid 2 (CB2) receptor agonism reduces lithium chloride-induced vomiting in Suncus murinus and nausea-induced conditioned gaping in rats

We aimed to investigate the potential anti-emetic and anti-nausea properties of targeting the cannabinoid 2 (CB2) receptor. We investigated the effect of the selective CB2 agonist, HU-308, on lithium chloride- (LiCl) induced vomiting in Suncus murinus (S. murinus) and conditioned gaping (nausea-induced behaviour) in rats. Additionally, we determined whether these effects could be prevented by pretreatment with AM630 (a selective CB2 receptor antagonist/inverse agonist). In S. murinus, HU-308 (2.5, 5mg/kg, i.p.) reduced, but did not completely block, LiCl-induced vomiting; an effect that was prevented with AM630. In rats, HU-308 (5mg/kg, i.p.) suppressed, but did not completely block, LiCl-induced conditioned gaping to a flavour; an effect that was prevented by AM630. These findings are the first to demonstrate the ability of a selective CB2 receptor agonist to reduce nausea in animal models, indicating that targeting the CB2 receptor may be an effective strategy, devoid of psychoactive effects, for managing toxin-induced nausea and vomiting.

Administration of olanzapine as an antiemetic agent changes glucose homeostasis in cisplatin-treated rats

We investigated the effects of olanzapine on cisplatin-induced pica (the consumption of non-nutrient materials such as kaolin) and glucose homeostasis in rats to clarify the effects of olanzapine when used as an anti-emetic drug. Rats were injected intraperitoneally (i.p.) with either 5 mg/kg cisplatin or saline. Additionally, 2 or 10 mg/kg olanzapine were administered i.p. to the rats 10 min before the administration of cisplatin and subsequently administered every 24 h for 3 d. Kaolin and food intake was measured using an automatic monitoring apparatus. Plasma glucose levels were measured by an enzyme electrode method. The plasma levels of insulin and intact proinsulin were measured by enzyme-linked immunosorbent assay (ELISA). The proinsulin-to-insulin (P/I) ratio was calculated. Cisplatin significantly increased kaolin intake, but decreased food intake and body weight up to 72 h. Olanzapine had no effect on these parameters. Neither olanzapine nor cisplatin alone had a significant effect on the plasma levels of glucose, insulin, or proinsulin. However, a combination of olanzapine and cisplatin significantly decreased plasma insulin levels, but increased plasma intact proinsulin levels and the P/I ratio. Our results suggest that an additive deterioration of insulin-secreting beta-cell function and disturbance of glucose homeostasis should be considered during treatment of patients with olanzapine for cisplatin-induced nausea and vomiting.

Electroacupuncture alleviates cisplatin-induced nausea in rats

Objective

Acupuncture has been shown to be effective for the treatment of chemotherapy-related nausea and vomiting. The aim of this study was to explore the mechanisms of action underlying the anti-emetic effect of electroacupuncture (EA).

Design

Forty-eight rats received saline (n=12) or 6 mg/kg cisplatin (n=36) to establish a chemotherapy-induced nausea and vomiting model. EA was performed at CV12 (n=12), bilateral PC6 (n=12), or sham points (n=12) 3 days before and 1–2 days after cisplatin administration (4–5 times in total), at 0.5–1 mA intensity and 2/15 Hz frequency for 10 min. Kaolin intake, food intake and bodyweight change were evaluated as markers of nausea and vomiting severity. Concentrations of serotonin (5-hydroxytryptamine, 5-HT) in the duodenum and c-Fos expression in the nucleus of the solitary tract (NTS) were measured using high performance liquid chromatography and immunohistochemistry, respectively.

Results

Cisplatin administration led to increased kaolin intake and reduced food intake and bodyweight over the following 2 days. EA at CV12 significantly reversed the cisplatin-induced change in kaolin intake (on days 1 and 2) and food intake and bodyweight (on day 1). EA at CV12 also attenuated the cisplatin-induced increase in 5-HT in the duodenum and suppressed c-Fos expression in the NTS. EA at PC6 influenced kaolin intake (on day 1 only) and c-Fos expression, but had no statistically significant effect on food intake, bodyweight or 5-HT expression.

Conclusions

This study demonstrated beneficial effects of EA on chemotherapy-induced nausea and vomiting in a rat model. The anti-emetic effect of EA may be mediated through inhibition of 5-HT secretion in the duodenum and activity of the NTS.

Involvement of substance P in the development of cisplatin-induced acute and delayed pica in rats

BACKGROUND AND PURPOSE

Although substance P (SP) and neurokinin NK1 receptors have been reported to be involved in cisplatin-induced acute and delayed emesis, their precise roles remain unclear. Pica, the consumption of non-nutrient materials such as kaolin in rats, can be used as a model of nausea in humans. We investigated the time-dependent changes in cisplatin-induced pica and the involvement of SP and NK1 receptors in this behaviour.

EXPERIMENTAL APPROACH

Rats were administered cisplatin with or without a daily injection of a 5-HT3 receptor antagonist (granisetron) or an NK1 receptor antagonist (aprepitant), and kaolin intake was then monitored for 5 days. The effects of granisetron on the cisplatin-induced expression of preprotachykinin-A (PPT-A) mRNA, which encodes mainly for SP, and on SP release in the medulla, measured by in vivo brain microdialysis, were also investigated.

KEY RESULTS

Cisplatin induced pica within 8 h of its administration that continued for 5 days. Granisetron inhibited the acute phase (day 1), but not the delayed phase (days 2-5), of pica, whereas aprepitant abolished both phases. Within 24 h of the injection of cisplatin, PPT-A mRNA expression and SP release in the medulla were significantly increased; these findings lasted during the observation period and were inhibited by granisetron for up to 24 h.

CONCLUSIONS AND IMPLICATIONS

The profiles of cisplatin-induced pica in rats are similar to clinical findings for cisplatin-induced emesis in humans, and we showed that SP production in the medulla and activation of NK1 receptors are involved in this cisplatin-induced pica.

Evaluating the various phases of cisplatin-induced emesis in rats

Use of cisplatin as a chemotherapeutic agent causes acute and delayed emesis. Kaolin, saccharin solution and normal feed consumption have been evaluated as an index of cisplatin-induced emesis in rats; however, the most preferable of these methods for evaluating the various phases of emesis remains unclear. In the current study, kaolin, saccharin solution and normal feed consumption following cisplatin administration (6 mg/kg intraperitoneally) were simultaneously investigated in rats. Kaolin consumption increased significantly following cisplatin administration and was attenuated by granisetron administration 0-24 h following the injection. Saccharin solution consumption, however, decreased significantly 0-48 h following cisplatin administration, however, was attenuated by administration of granisetron within 0-24 h only. A reduced intake of normal feed was observed in the control group and was reversed by granisetron within the 0-72 h period. The present study indicates that kaolin consumption may be evaluated as an index of cisplatin-induced acute emesis and saccharin solution consumption may be evaluated as an index of delayed emesis, while normal feed consumption as an indicator of anorexia nervosa may be suitable to evaluate all phases of emesis and serve as an indicator of quality of life.

The influence of pemirolast on autonomic imbalance in rat cystitis model

Cyclophosphamide (CP) treatment is associated with the risk of haemorrhagic cystitis (HC). Moreover, CP-induced HC is complicated by autonomic nervous system (ANS) dysfunction. Pemirolast is thought to be a mast cell stabiliser that inhibits the release of many inflammatory mediators and sensory neuropeptides, and thus, it may be considered a potential chemoprotective HC agent. The aim of the study was to indirectly estimate the effect of pemirolast in experimental HC by measuring ANS activity with the heart rate variability (HRV) method. In CP-treated rats, we found a decreasing trend of overall autonomic activity, together with an imbalance between the main components, and a dominant very low frequency (VLF) power component. Pemirolast treatment did not improve the total HRV power value or the main non-normalized HRV components. Moreover, CP-HC animals treated with pemirolast displayed a different disproportion of normalized spectral components as compared to both control and CP-HC animals without pemirolast treatment, with the balance between normalized low frequency (nLF) and normalized high frequency (nHF) shifted towards nLF. This finding, together with a relatively high VLF tension, indicates that the pemirolast treatment resulted in high sympathetic activity that may contribute to HC exacerbation; thus, this agent seems to be ineffective in CP-induced HC.