Z-505, an Oral Ghrelin Receptor Agonist, Attenuates Anorexia After Total Gastrectomy in Rats.

BACKGROUND: Anorexia is a serious problem in patients with gastric cancer who have undergone gastrectomy. Ghrelin, an orexigenic hormone primarily secreted from the stomach, has been proposed to prevent anorexia. Significant reduction in plasma ghrelin levels after gastrectomy may contribute to lack of appetite and weight loss. In this study, we investigated the effects of Z-505, a ghrelin receptor agonist, on anorexia after total gastrectomy (TG) in a rat model. METHODS AND MATERIALS: Male Sprague-Dawley rats were used to establish a TG model, and then sham-operated (control) and TG rats were randomly assigned to four subgroups receiving administration of Z-505 (100 mg/kg, p.o., once daily) or vehicle for 14 d from day 14 to day 27 after TG. The food intake, body weight, and fat weight were evaluated during the test period. Moreover, the neuronal activity in the hypothalamus was evaluated on day 21 to investigate the mechanism of action of Z-505. RESULTS: In TG rats, Z-505 significantly improved the decrease in cumulative food intake induced by the surgery over 14 d (TG + vehicle; 213.8 ± 15.3 g, n = 12 versus TG + Z-505; 258.2 ± 13.1 g, n = 14, P < 0.05). Z-505 also significantly increased fat weight and had a milder effect on body weight over 14 d. In addition, Z-505 significantly increased the number of c-Fos-positive cells in the hypothalamic arcuate nucleus (TG + vehicle; 17.8 ± 2.0, n = 12 versus TG + Z-505; 72.2 ± 11.8, n = 12, P < 0.001). CONCLUSIONS: Z-505 may be a useful therapeutic treatment for anorexia after TG.

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.

Acotiamide hydrochloride (Z-338) enhances gastric motility and emptying by inhibiting acetylcholinesterase activity in rats.

In clinical trials, acotiamide hydrochloride (acotiamide: Z-338) has been reported to be useful in the treatment of functional dyspepsia. Here, we investigated the effects of acotiamide on gastric contraction and emptying activities in rats in comparison with itopride hydrochloride (itopride) and mosapride citrate (mosapride). We also examined in vitro the compound's inhibitory effect on acetylcholinesterase (AChE) activity derived from rat stomach. In in vivo studies, acotiamide (30 and 100mg/kg s.c.) and itopride (100mg/kg s.c.) markedly enhanced normal gastric antral motility in rats. In gastric motility dysfunction models, acotiamide (100mg/kg s.c.) and itopride (100mg/kg s.c.) improved both gastric antral hypomotility and the delayed gastric emptying induced by clonidine, an α(2)-adrenoceptor agonist. In contrast, mosapride (10mg/kg s.c.) had no effect on these models. Like the AChE inhibitors itopride (30 mg/kg s.c.) and neostigmine (10 µg/kg s.c.), acotiamide (10mg/kg s.c.) also clearly enhanced gastric body contractions induced by electrical stimulation of the vagus, which were abolished by atropine and hexamethonium, whereas mosapride (3 and 10mg/kg s.c.) did not. In in vitro studies, acotiamide concentration-dependently inhibited rat stomach-derived AChE activity (IC(50)=2.3 µmol/l). In addition, stomach tissue concentrations of acotiamide after administration at 10mg/kg s.c. were sufficient to produce inhibition of AChE activity in rat stomach. These results suggest that acotiamide stimulates gastric motility and improves gastric motility dysfunction in rats by inhibiting AChE activity, and may suggest a role for acotiamide in improving gastric motility dysfunction in patients with functional dyspepsia.

Concentration dependence of 5-aminosalicylic acid pharmacological actions in intestinal mucosa after oral administration of a pH-dependent formulation.

Asacol, a medication that delivers delayed release 5-aminosalicylic acid (5-ASA), is a useful therapeutic agent for inflammatory bowel disease (IBD), but the relationship between its pharmacological actions and intestinal concentrations has not been studied in detail. Therefore, our aim was to assess 5-ASA's pharmacological actions as a function of its concentration at its target site. We first evaluated 5-ASA's release profiles in vitro by the paddle method and found that Asacol starts to release 5-ASA at pH ≥ 7. Orally administered Asacol pharmacokinetic parameters were evaluated in dogs. Asacol's T(max) was much longer than that of the time-dependent release 5-ASA formulation. We also determined 5-ASA's distribution in the intestinal mucosa and found that it is effectively delivered there by Asacol. These results indicated that Asacol released 5-ASA in a pH-dependent manner, resulting in efficient delivery to the large intestine. We also compared the mucosal 5-ASA concentrations with the IC(50) values for scavenging free radicals or suppressing LTB(4) production. The 5-ASA concentration in the large intestine was higher than IC(50) values necessary to suppress inflammatory processes. We also report the release characteristics of Asacol and the targeted delivery of 5-ASA to affected sites in IBD patients.

Pharmacological evaluation of analgesic effects of the cholecystokinin2 receptor antagonist Z-360 in mouse models of formalin- and cancer-induced pain.

Z-360, a novel cholecystokinin(2) (CCK(2)) receptor antagonist, has been developed as a therapeutic drug for pancreatic cancer and showed pain relief action in phase Ib/IIa clinical trial. This study was attempted to elucidate the analgesic efficacy of Z-360 in mice. Oral administration of Z-360 (30-300 mg/kg) showed a dose-dependent inhibitory effect on the late phase of nociceptive responses to formalin. YF476, another CCK(2) receptor antagonist, was without effects at 1 and 10 mg/kg. In contrast, the CCK(1) receptor antagonist devazepide inhibited the nociceptive responses to formalin. In a mouse model of cancer pain, significant anti-allodynic effect of Z-360 was observed after single and repeated oral administration of 100 and 300 mg/kg doses. Anti-allodynic effect was also observed after repeated administration of devazepide. Combined single treatment with morphine and Z-360 caused an increase inhibition of pain-related responses in the pain models produced by formalin and cancer. Although Z-360 has lower affinity for CCK(1) receptor than for CCK(2) receptor, Z-360 exhibited an inhibitory effect on sulfated CCK-8-induced gallbladder emptying, a CCK(1) receptor-mediated effect, at a dose of 100 mg/kg. These results suggest that Z-360 inhibits inflammatory and cancer pain probably through the blockade of CCK(1) receptors. Z-360 is expected to become a useful drug for the pancreatic cancer with analgesic effects as well as the prolongation of survival.

[Emergency microlaryngosurgery for a huge post-intubation laryngeal granuloma].

A 55-year-old woman who had undergone esophagectomy 3 months earlier developed a huge post-intubation laryngeal granuloma. She was scheduled for emergency microlaryngosurgery. Anesthesia was induced with 8% sevoflurane in oxygen under spontaneous respiration. After confirming no airway compromise, the spontaneous respiration was obtunded by forced manual ventilation without using a muscle relaxant. The trachea was intubated easily with an endotracheal tube. Anesthesia was maintained with sevoflurane and nitrous oxide supplemented with intravenous fentanyl. The granuloma removed was 11 x 8 mm in diameter. There were no respiratory complications during and after anesthesia and surgery.