Cisplatin-induced Anorexia Research Articles

Effects of a histamine H4 receptor antagonist on cisplatin-induced anorexia in mice

Cancer chemotherapy often induces gastrointestinal symptoms such as anorexia, nausea, and vomiting. Antiemetic agents are effective in inhibiting nausea and vomiting, but patients still experience anorexia. We previously reported that chemotherapeutic agent-induced anorexia is associated with an increase of inflammatory cytokines. Other studies also reported that antagonism of the histamine H4 receptor is anti-inflammatory. In this study, we investigated the involvement of the H4 receptor in the development of chemotherapy-induced anorexia in mice. Cisplatin-induced anorexia occurred within 24 h of its administration and continued for 3 days. The early phase (day 1), but not the delayed phase (days 2 and 3), of anorexia was inhibited by the daily injection of a 5-HT3 receptor antagonist (granisetron). However, a corticosteroid (dexamethasone) or selective H4 receptor antagonist (JNJ7777120) abolished the delayed phases of anorexia. Cisplatin significantly increased TNF-α mRNA expression in the hypothalamus and spleen, and the period of expression increase paralleled the onset period of anorexia. In addition, pretreatment with JNJ7777120 completely inhibited the increased expression. These results suggest that TNF-α mRNA expression via H4 receptors may contribute to the development of cisplatin-induced anorexia, and that H4 receptor antagonists are potentially useful treatments.

Protective Effect of D-Methionine on Body Weight Loss, Anorexia, and Nephrotoxicity in Cisplatin-Induced Chronic Toxicity in Rats.

D-methionine is a sulfur-containing amino acid that can act as a potent antioxidant. Anorexia and nephrotoxicity are side effects of cisplatin. The protective effects of D-methionine on cisplatin-induced anorexia and renal injury were investigated. The model of chronic cisplatin administration (5 mg/kg body weight) involved intraperitoneal injection on days 1, 8, and 15 and oral D-methionine (300 mg/kg body weight) coadministration daily for 20 days. On the 21st day of treatment, food intake and body weight in the cisplatin-treated group significantly decreased by 52% and 31%, respectively, when compared with a control group. D-methionine coadministration with cisplatin decreased food intake and body weight by 29% and 8%, respectively. In cisplatin-treated rats, white blood cell, mean corpuscular volume, and platelet values significantly decreased, while mean corpuscular hemoglobin concentration significantly increased by 8.6% when compared with control rats. Cisplatin administration resulted in significantly decreased feeding efficiency, elevated renal oxidative stress, and reduced antioxidative activity. Leukocyte infiltration, tubule vacuolization, tubular expansion, and swelling were observed in the kidneys of cisplatin-treated rats. Oral D-methionine exhibited an antianorexic effect, with improvement in food intake, feeding efficiency, and hematological toxicities, as well as a protective effect against nephrotoxicity by elevated antioxidative activity. D-methionine may serve as a chemoprotectant in patients receiving cisplatin as part of a chemotherapy regimen.

Z-505 hydrochloride ameliorates chemotherapy-induced anorexia in rodents via activation of the ghrelin receptor, GHSR1a

Despite its therapeutic advantages, chemotherapy with anti-cancer drugs can cause adverse effects, including anorexia and weight loss. Although most patients with cancer suffer from anorexia during chemotherapy, resulting in the need to suspend or cease treatment and thereby worsening prognosis, treatment options for anorexia remain limited. Ghrelin is an orexigenic hormone that has been proposed to prevent anorexia. To investigate the potential of ghrelin receptor agonists, synthetic small-molecule compounds, as preventive therapies for chemotherapy-induced anorexia, we studied the effects of Z-505 hydrochloride (Z-505), a new oral growth hormone secretagogue receptor 1a (GHSR1a) agonist, in cisplatin- and 5-fluorouracil (5-FU)-induced anorexia animal models. The agonistic activity of Z-505 was examined using calcium flux assays in Chinese hamster ovary (CHO-K1) cells stably expressing rat or mouse GHSR1a. Z-505 showed agonistic activity for rat GHSR1a and mouse GHSR1a, with a half maximal effective concentration (EC50) of 2.08nM and 5.46nM, respectively. In a cisplatin-induced anorexia rat model, administration of Z-505 (30, 100 or 300mg/kg, p.o., once daily) significantly improved the cisplatin-induced reduction in food intake and body weight. In addition, treatment with Z-505 (100 or 300mg/kg, p.o., once daily) prevented the 5-FU-induced decrease in food intake and body weight in the 5-FU-induced mouse model. Our results demonstrate that Z-505 ameliorates cisplatin- and 5-FU-induced anorexia through the activation of the ghrelin receptor, GHSR1a, suggesting its usefulness in the preventive treatment of anorexia during chemotherapy.

Possible involvement of central oxytocin in cisplatin-induced anorexia in rats.

During cancer chemotherapy, drugs such as 5-HT3 receptor antagonists have typically been used to control vomiting and anorexia. We examined the effects of oxytocin (OXT), which has been linked to appetite, on cisplatin-induced anorexia in rats. Fos-like immunoreactivity (Fos-LI) expressed in the supraoptic nucleus (SON), the paraventricular nucleus (PVN), the area postrema and the nucleus of the solitary tract (NTS) after intraperitoneal (ip) administration of cisplatin. We also examined the fluorescence intensity of OXT-mRFP1 after ip administration of cisplatin in OXT-mRFP1 transgenic rats. The mRFP1 fluorescence intensity was significantly increased in the SON, the PVN, and the NTS after administration of cisplatin. The cisplatin-induced anorexia was abolished by OXT receptor antagonist (OXTR-A) pretreatment. In the OXT-LI cells, cisplatin-induced Fos expression in the SON and the PVN was also suppressed by OXTR-A pretreatment. These results suggested that central OXT may be involved in cisplatin-induced anorexia in rats.

Excitatory Hindbrain–Forebrain Communication Is Required for Cisplatin-Induced Anorexia and Weight Loss

Cisplatin chemotherapy is commonly used to treat cancer despite severe energy balance side effects. In rats, cisplatin activates nucleus tractus solitarius (NTS) projections to the lateral parabrachial nucleus (lPBN) and calcitonin-gene related peptide (CGRP) projections from the lPBN to the central nucleus of the amygdala (CeA). We demonstrated previously that CeA glutamate receptor signaling mediates cisplatin-induced anorexia and body weight loss. Here, we used neuroanatomical tracing, immunofluorescence, and confocal imaging to demonstrate that virtually all NTS→lPBN and lPBN→CeA CGRP projections coexpress vesicular glutamate transporter 2 (VGLUT2), providing evidence that excitatory projections mediate cisplatin-induced energy balance dysregulation. To test whether lPBN→CeA projection neurons are required for cisplatin-induced anorexia and weight loss, we inhibited these neurons chemogenetically using a retrograde Cre-recombinase-expressing canine adenovirus-2 in combination with Cre-dependent inhibitory Designer Receptors Exclusive Activated by Designer Drugs (DREADDs) before cisplatin treatment. Inhibition of lPBN→CeA neurons attenuated cisplatin-induced anorexia and body weight loss significantly. Using a similar approach, we additionally demonstrated that inhibition of NTS→lPBN neurons attenuated cisplatin-induced anorexia and body weight loss significantly. Together, our data support the view that excitatory hindbrain–forebrain projections are necessary for cisplatin9s untoward effects on energy intake, elucidating a key neuroanatomical circuit driving pathological anorexia and weight loss that accompanies chemotherapy treatment. <b>SIGNIFICANCE STATEMENT</b> Chemotherapy treatments are commonly used to treat cancers despite accompanying anorexia and weight loss that may limit treatment adherence and reduce patient quality of life. Strikingly, we lack a neural understanding of, and effective treatments for, chemotherapy-induced anorexia and weight loss. The current data characterize the excitatory nature of neural projections activated by cisplatin in rats and reveal the necessity of specific hindbrain–forebrain projections for cisplatin-induced anorexia and weight loss. Together, these findings help to characterize the neural mechanisms mediating cisplatin-induced anorexia, advancing opportunities to develop better-tolerated chemotherapies and adjuvant therapies to prevent anorexia and concurrent nutritional deficiencies during cancer treatment.

Excitatory Hindbrain-Forebrain Communication Is Required for Cisplatin-Induced Anorexia and Weight Loss.

Chemotherapy treatments are commonly used to treat cancers despite accompanying anorexia and weight loss that may limit treatment adherence and reduce patient quality of life. Strikingly, we lack a neural understanding of, and effective treatments for, chemotherapy-induced anorexia and weight loss. The current data characterize the excitatory nature of neural projections activated by cisplatin in rats and reveal the necessity of specific hindbrain-forebrain projections for cisplatin-induced anorexia and weight loss. Together, these findings help to characterize the neural mechanisms mediating cisplatin-induced anorexia, advancing opportunities to develop better-tolerated chemotherapies and adjuvant therapies to prevent anorexia and concurrent nutritional deficiencies during cancer treatment.

Sip-jeon-dea-bo-tang, a traditional herbal medicine, ameliorates cisplatin-induced anorexia via the activation of JAK1/STAT3-mediated leptin and IL-6 production in the fat tissue of mice.

Despite its therapeutic advantages, chemotherapy can also cause adverse effects, including anorexia and loss of appetite. Although numerous patients with cancer have been reported to suffer from anorexia during or following chemotherapy, treatment options for anorexia remain to be determined. In Asian countries, traditional medicines are widely used to treat problems with appetite; sip-jeon-dea-bo-tang (SJDBT) is one of those medicines used for the treatment of anorexia. The present study demonstrated that SJDBT ameliorated cisplatin-induced anorexia. In a mouse model of chemotherapy-induced anorexia, oral administration of SJDBT prevented the cisplatin-induced reduction of food intake, inhibiting weight loss. The results of multiplex assays showed that SJDBT only altered the levels of interleukin (IL)-6 and leptin in the serum and fat tissue. In addition, SJDBT maintained the serum leptin level and increased the serum IL-6 level, whereas cisplatin reduced the levels of both serum leptin and IL-6. Furthermore, SJDBT was revealed to increase the levels of leptin and IL-6 in the fat tissue by activating the JAK1/STAT3 signaling pathway. In conclusion, the present results revealed that SJDBT ameliorated cisplatin-induced anorexia, suggesting its usefulness in the prevention of anorexia during chemotherapy.

Hindbrain GLP-1 receptor mediation of cisplatin-induced anorexia and nausea

While chemotherapy-induced nausea and vomiting are clinically controlled in the acute (<24h) phase following treatment, the anorexia, nausea, fatigue, and other illness-type behaviors during the delayed phase (>24h) of chemotherapy are largely uncontrolled. As the hindbrain glucagon-like peptide-1 (GLP-1) system contributes to energy balance and mediates aversive and stressful stimuli, here we examine the hypothesis that hindbrain GLP-1 signaling mediates aspects of chemotherapy-induced nausea and reductions in feeding behavior in rats. Specifically, hindbrain GLP-1 receptor (GLP-1R) blockade, via 4th intracerebroventricular (ICV) exendin-(9-39) injections, attenuates the anorexia, body weight reduction, and pica (nausea-induced ingestion of kaolin clay) elicited by cisplatin chemotherapy during the delayed phase (48h) of chemotherapy-induced nausea. Additionally, the present data provide evidence that the central GLP-1-producing preproglucagon neurons in the nucleus tractus solitarius (NTS) of the caudal brainstem are activated by cisplatin during the delayed phase of chemotherapy-induced nausea, as cisplatin led to a significant increase in c-Fos immunoreactivity in NTS GLP-1-immunoreactive neurons. These data support a growing body of literature suggesting that the central GLP-1 system may be a potential pharmaceutical target for adjunct anti-emetics used to treat the delayed-phase of nausea and emesis, anorexia, and body weight loss that accompany chemotherapy treatments.

Glutamate Receptors in the Central Nucleus of the Amygdala Mediate Cisplatin-Induced Malaise and Energy Balance Dysregulation through Direct Hindbrain Projections.

To treat cancer effectively, patients must follow prescribed chemotherapy treatments without interruption, yet most cancer treatments produce side effects that devastate quality of life (e.g., nausea, vomiting, anorexia, weight loss). Although hundreds of thousands of patients undergo chemotherapies each year, the neural mechanisms mediating their side effects are unknown. The current data outline a neural circuit activated by cisplatin chemotherapy and demonstrate that glutamate signaling in the amygdala, arising from hindbrain projections, is required for the full expression of cisplatin-induced malaise, anorexia, and body weight loss. Together, these data help to characterize the neural circuits and neurotransmitters mediating chemotherapy-induced energy balance dysregulation, which will ultimately provide an opportunity for the development of well tolerated cancer and anti-emetic treatments.

Anorexia in human and experimental animal models: physiological aspects related to neuropeptides.

Anorexia, a loss of appetite for food, can be caused by various physiological and pathophysiological conditions. In this review, firstly, clinical aspects of anorexia nervosa are summarized in brief. Secondly, hypothalamic neuropeptides responsible for feeding regulation in each hypothalamic nucleus are discussed. Finally, three different types of anorexigenic animal models; dehydration-induced anorexia, cisplatin-induced anorexia and cancer anorexia-cachexia, are introduced. In conclusion, hypothalamic neuropeptides may give us novel insight to understand and find effective therapeutics strategy essential for various kinds of anorexia.

Herbal medicines for the treatment of cancer chemotherapy-induced side effects.

Accumulating evidence suggests that Japanese herbal medicines, called Kampo, have beneficial effects on cancer chemotherapy-induced side effects. Rikkunshito ameliorates cisplatin-induced anorexia through an antagonistic effect on the 5-HT receptors and by increasing the serum ghrelin levels. Hangeshashinto improves irinotecan-induced diarrhea and chemotherapy-induced mucositis by inhibiting the activity of β-glucuronidase as well as the synthesis of prostaglandin E2. Goshajinkigan prevents oxaliplatin-induced neurotoxicity, possibly through suppressing functional alterations of the transient receptor potential channels. In this review, we will summarize the currently available literature regarding the clinical efficacy and potential mechanisms of Kampo medicines in the treatment of cancer chemotherapy-induced side effects.

Preventive effect of rikkunshito, traditional Japanese medicine, for chemotherapy-induced nausea and vomiting.

131 Background: Supportive therapies are being developed for chemotherapy-induced nausea and vomiting (CINV). Rikkunshito is a Kanpo medicine, which is a part of traditionally practiced Japanese-based ancient Chinese medicine. It has been reported to be effective against cisplatin-induced anorexia in rats. In the present study, we evaluated the preventive effect of Rikkunshito for CINV in patients receiving high-dose cisplatin. Methods: We selected subjects who received chemotherapy including cisplatin (≥60mg/m2) for gastric or esophageal cancer between April 2010 and August 2012 at our institution. We targeted 20 cases treated without a reduction in the anti-cancer medication in the second course and added 7.5g/day of Rikkunshito, orally administered for seven days, to their second course treatment regimen. All cases were treated with 5-HT3 receptor antagonist and steroid, and palonosetron for the prevention of CINV in their first and second courses. We evaluated the complete response (CR, defined as no emesis and no rescue medication) rate and other toxicity, according to CTCAE v4.0, of the first and second courses. Results: The median age of the patients was 63 years (range, 49–77 years). The chemotherapy regimens were cisplatin + 5-FU in 15 cases with esophageal cancer, cisplatin + S-1 in five cases with gastric cancer. Anorexia in the first course was grade 0/1/2 = 5/11/4, but had been mitigated in the second course to grade 0/1/2 = 12/6/2 (P = 0.042). CR rate was 75.0% in the first course (95% CI, 56.0%–94.0%) and by the second course had improved to 95.0% (95% CI, 85.4%–100%). And about the other major toxicity, there was no significant difference between first and second courses. Conclusions: These results suggest that Rikkunshito has the potential to improve CINV in patients receiving high-dose cisplatin.

Pathophysiologic Basis of Anorexia: Focus on the Interaction between Ghrelin Dynamics and the Serotonergic System

Anorexia is an important issue in the management of elderly patients with cancer because it contributes to the development of malnutrition, increases morbidity and mortality, and negatively affects patients' quality of life. This review summarizes the potential mechanisms of the development of anorexia in three animal models that mimic the situations commonly seen in elderly patients receiving chemotherapy. Cisplatin-induced anorexia is attributable to a decrease in peripheral and central ghrelin secretion caused by the stimulation of serotonin (5-hydroxytryptamine; 5-HT)2B and 5-HT2C receptors via 5-HT secretion. Age-associated anorexia is caused by an increase in plasma leptin, which results from disturbed reactivity of ghrelin in the hypothalamus and regulation of ghrelin secretion. Environmental change causes the activation of central 5-HT1B and 5-HT2C receptors and the melanocortin-4 receptor system, resulting in a decrease in circulating ghrelin levels which lowers food intake. New therapeutic approaches based on these pathophysiological mechanisms are warranted for the treatment of anorexia in cancer patients, especially elderly ones.

Preventive effect of rikkunshito, traditional Japanese medicine, for chemotherapy-induced nausea and vomiting.

135 Background: Supportive therapies are being developed for chemotherapy-induced nausea and vomiting (CINV). Rikkunshito is a Kanpo medicine, which is a part of traditionally practiced Japanese-based ancient Chinese medicine. It has been reported to be effective against cisplatin-induced anorexia in rats. In the present study, we evaluated the preventive effect of rikkunshito for CINV in patients receiving high-dose cisplatin. Methods: We selected subjects who received chemotherapy including cisplatin (≥60mg/m2) for gastric or esophageal cancer between April 2008 and July 2011 at our institution. We targeted 26 cases treated without a reduction in the anti-cancer medication in the second course and added 7.5g/day of rikkunshito, orally administered for seven days, to their second course treatment regimen. All cases were treated with 5-HT3 receptor antagonist and steroid, and 12 cases were treated with palonosetron for the prevention of CINV in their first and second courses. We evaluated the complete response (CR, defined as no emesis and no rescue medication) rate and other toxicity, according to CTCAE v4.0, of the first and second courses. Results: The median age of the patients was 67 years (range, 49–77 years). There were nine cases of gastric cancer and 17 cases of esophageal cancer. The chemotherapy regimens were cisplatin + irinotecan in two cases, cisplatin + 5-FU in 15 cases, cisplatin + S-1 in seven cases and cisplatin + 5-FU + docetaxel in two cases. Six cases received concomitant radiation therapy. Anorexia in the first course was grade 0/1/2 = 4/12/10, but had been mitigated in the second course to grade 0/1/2 = 11/11/4 (P = 0.020). CR rate was 69.3% in the first course (95% CI, 51.6%–87.0%) and by the second course had improved to 88.5% (95% CI, 76.2%–100%) (P = 0.089). And about the other major toxicity, there was no significant difference between first and second courses. Conclusions: These results suggest that rikkunshito has the potential to improve CINV in patients receiving high-dose cisplatin.

Rikkunshito, a traditional Japanese medicine, suppresses cisplatin-induced anorexia in humans

BackgroundThe aim of this study was to investigate the effects of Rikkunshito on ghrelin secretion and on cisplatin-induced anorexia in humans.MethodsThe study was performed as a crossover design, and ten unresectable or relapsed gastric cancer patients were randomly divided into two groups. Group A (n = 5) was started on Rikkunshito (2.5 g three times daily, orally) from the first course of chemotherapy and followed by a second course without Rikkunshito. A treatment with reversed order was performed for Group B (n = 5). All patients received combined chemotherapy with S-1 plus cisplatin. The primary endpoint was the amount of oral intake, and the categories of scales of anorexia, nausea, and vomiting; secondary endpoints included the plasma concentration of acylated ghrelin.ResultsIn the Rikkunshito-on period, no decrease of the plasma concentration of acylated ghrelin induced by cisplatin was observed. The average oral intake in the Rikkunshito-on period was significantly larger than that in the Rikkunshito-off period, and the grade of anorexia was significantly lower in the Rikkunshito-on period than in the Rikkunshito-off period.ConclusionRikkunshito appeared to prevent anorexia induced by cisplatin, resulting in effective prophylactic administration of chemotherapy with cisplatin, and patients could continue their treatments on schedule.

10-Gingerol, a component of rikkunshito, improves cisplatin-induced anorexia by inhibiting acylated ghrelin degradation

Rikkunshito (RKT), a Japanese traditional medicine, has been shown to stimulate food intake in rats with cisplatin-induced anorexia; however, the underlying mechanisms remain unknown. In this study, we investigated whether RKT is involved in the degradation of peripheral ghrelin. RKT inhibited decreases in plasma ghrelin level and enhanced acyl- to desacyl-ghrelin (A/D) ratio in cisplatin-treated rats. Several components of RKT demonstrated inhibitory activity against ghrelin deacylating enzymes. In addition, 10-gingerol, a component of RKT, inhibited exogenous ghrelin deacylation. Therefore, RKT may enhance plasma acyl-ghrelin level, at least in part, by inhibiting the circulating ghrelin degrading enzyme.

The effect of traditional Japanese medicine (Kampo) on gastrointestinal function

Traditional Japanese medicine (Kampo) is used to treat various disorders of the gastrointestinal tract in Japan, where it is fully integrated into the modern healthcare system. Recently, scientific research on herbal medicine in Japan has been reported in English journals. The objective of the current review is to introduce two traditional Japanese medicines and to provide evidenced-based information regarding their use. Daikenchuto, which consists of three different herbs, is the most frequently prescribed traditional Japanese medicine in Japan. Daikenchuto stimulates gastrointestinal motility though a neural reflex involving presynaptic cholinergic and 5-HT3 receptors. Daikenchuto improves postoperative bowel motility and postoperative ileus. Furthermore, it is reported to cause an increase in gastrointestinal hormones (motilin, vasoactive intestinal peptide, and calcitonin gene-related peptide) and intestinal blood flow. Rikkunshito, a traditional Japanese medicine consisting of eight herbs, is thought to stimulate gastrointestinal motility and ghrelin secretion. Rikkunshito is effective for improving the symptoms of functional dyspepsia, gastroesophageal reflux disease, and cisplatin-induced anorexia and vomiting. Traditional Japanese medicine has the potential to be used successfully in the treatment of gastrointestinal disorders. Details regarding the physiological and clinical effects of traditional Japanese medicine must be further examined in order to become more widely accepted in other countries.

Reduced Ghrelin Secretion in the Hypothalamus of Rats due to Cisplatin-Induced Anorexia

Although chemotherapy with cisplatin is a widely used and effective cancer treatment, the undesirable gastrointestinal side effects associated with it, such as nausea, vomiting, and anorexia, markedly decrease patients' quality of life. To elucidate the mechanism underlying chemotherapy-induced anorexia, focusing on the hypothalamic ghrelin secretion-anorexia association, we measured hypothalamic ghrelin secretion in fasted and cisplatin-treated rats. Hypothalamic ghrelin secretion changes after vagotomy or administration of cisplatin. Cisplatin + rikkunshito, a serotonin 2C receptor antagonist or serotonin 3 receptor antagonist, was investigated. The effects of intracerebroventricular (icv) administration of ghrelin or the serotonin 2C receptor antagonist SB242084 on food intake were also evaluated in cisplatin-treated rats. Hypothalamic ghrelin secretion significantly increased in 24-h-fasted rats compared to freely fed rats and was markedly reduced 24 and 48 h after cisplatin treatment in cisplatin-treated rats compared to saline-treated rats, although their plasma ghrelin levels were comparable. In cisplatin-treated rats, icv ghrelin administration reversed the decrease in food intake, vagotomy partially restored hypothalamic ghrelin secretion, and hypothalamic serotonin 2C receptor mRNA expression increased significantly. Administration of rikkunshito (an endogenous ghrelin enhancer) or a serotonin 2C receptor antagonist reversed the decrease in hypothalamic ghrelin secretion and food intake 24 h after cisplatin treatment. Cisplatin-induced anorexia is mediated through reduced hypothalamic ghrelin secretion. Cerebral serotonin 2C receptor activation partially induces decrease in hypothalamic ghrelin secretion, and rikkunshito suppresses cisplatin-induced anorexia by enhancing this secretion.

W1364 Role of Hypothalamic Ghs-R1a on Appetite Loss During Chemotherapy

Background/Aim: Because ghrelin is a strong orexigenic peptide, targeted depletion of the ghrelin receptor is expected to have a significant effect on feeding behavior. Although recent loss-of-function studies using GHS-R1a knockout animals have raised questions regarding the physiological significance of ghrelin on feeding, the roles of central GHS-R1a in anorexia models have not been investigated. To clarify that the gut-brain axis is associated with the regulation of appetite and the hypothalamic ghrelin signal, we investigated hypothalamic GHS-R1a gene expression and studied chemotherapy-induced dyspepsia in rats. Methods: We first examined the effects of an intracerebroventricular (ICV) injection of exogenous ghrelin on food intake with or without cisplatin treatment, as well as those of 48-h fasting and cisplatin or a 5-HT receptor agonist treatment on hypothalamic GHS-R1a mRNA expression. To identify the mechanism of the cisplatin-induced decrease in hypothalamic GHSR1a mRNA expression, we evaluated the effects of SB242084, a 5-HT2C receptor antagonist, and Rikkunshito (RKT), a ghrelin receptor activator (Endocrinology, 151, 2009) on hypothalamic GHS-R1a gene expression, as well as the effect of coadministration of a GHS-R1a antagonist on decreased food intake. Results: Compared to vehicle controls, ICV ghrelininjected rats (2 nmol/head) that were treated with cisplatin failed to reduce the decrease in food intake. Hypothalamic GHS-R1a gene expression was significantly enhanced during the 48-h fasting but was reduced after treatment with cisplatin or mCPP, a 5-HT2C receptor agonist (saline; 1.0 ± 0.08 vs. mCPP; 0.77 ± 0.06 relative mRNA, p = 0.0157, Steel's test), but not with 1B/2B receptor agonist treatment. The induced decrease was reversed by a 5HT2C receptor antagonist (cisplatin plus saline; 0.83 ± 0.06, and vs. relative mRNA level in cisplatin plus SB242084HCl, 1.2 ± 0.06, p = 0.026) or RKT (0.71 ± 0.06; cisplatin plus 500 mg/kg, 1.12 ± 0.09, p = 0.009; cisplatin plus 1000 mg/kg, 1.06 ± 0.09, p = 0.03), but not by granisetron or ondansetron, which are 5-HT3 receptor antagonists. The suppressive effect of cisplatin and mCPP on the decrease in food intake was abolished by coadministration of the GHS-R1a antagonist. Conclusion: Cisplatin-induced anorexia may worsen because of decreased hypothalamic GHS-R1a gene expression. Activation of the cerebral 5-HT2C receptor partially contributed to the decrease in GHS-R1a gene expression after cisplatin treatment.

W1363 Contribution of Serotonin 2C Receptor Activation to “Ghrelin Resistance” and Possible Therapy for Cisplatin-Induced Anorexia

W1363 Contribution of Serotonin 2C Receptor Activation to “Ghrelin Resistance” and Possible Therapy for Cisplatin-Induced Anorexia