GABAergic and glutamatergic neurons in the brain regulate phase II of migrating motor contractions in the Suncus murinus.

Gastric contractions exhibit characteristic motor patterns in the fasted state, known as migrating motor contractions (MMC). MMC consist of three periodically repeated phases (phase I, II and III) and are known to be regulated by hormones and the autonomic and enteric nervous systems. However, the central regulation of gastric contractions in the fasted state is not completely understood. Here, we have examined the central effects of motilin, ghrelin, γ-aminobutyric acid (GABA) and L-glutamate signaling on gastric MMC by using suncus (Suncus murinus) as an animal model, because of their similar gastric motor patterns to those observed in humans and dogs. Intracerebroventricular (i.c.v.) administration of motilin and ghrelin had no effect on phase I and II contractions, respectively. Conversely, i.c.v. administration of GABAA receptor antagonist, during phase I of the MMC, evoked phase II-like contractions and significantly increased the motility index (MI). This was compared with the i.c.v. administration of GABA which inhibited spontaneous phase II contractions with a significantly decreased MI. In addition, i.c.v. administration of L-glutamate during phase I also induced phase II-like irregular contractions with a significant increase in the MI. Taken together with previous findings, these results suggest that central GABAergic and glutamatergic signaling, with the coordination of both peripheral motilin and ghrelin, regulate phase II contractions of MMC in the fasted state.

Underlying mechanism of the cyclic migrating motor complex in Suncus murinus: a change in gastrointestinal pH is the key regulator.

In the fasted gastrointestinal (GI) tract, a characteristic cyclical rhythmic migrating motor complex (MMC) occurs in an ultradian rhythm, at 90-120 min time intervals, in many species. However, the underlying mechanism directing this ultradian rhythmic MMC pattern is yet to be completely elucidated. Therefore, this study aimed to identify the possible causes or factors that involve in the occurrence of the fasting gastric contractions by using Suncus murinus a small model animal featuring almost the same rhythmic MMC as that found in humans and dogs. We observed that either intraduodenal infusion of saline at pH 8 evoked the strong gastric contraction or continuously lowering duodenal pH to 3-evoked gastric phase II-like and phase III-like contractions, and both strong contractions were essentially abolished by the intravenous administration of MA 2029 (motilin receptor antagonist) and D-Lys3-GHRP6 (ghrelin receptor antagonist) in a vagus-independent manner. Moreover, we observed that the prostaglandin E2-alpha (PGE2-α) and serotonin type 4 (5HT4) receptors play important roles as intermediate molecules in changes in GI pH and motilin release. These results suggest a clear insight mechanism that change in the duodenal pH to alkaline condition is an essential factor for stimulating the endogenous release of motilin and governs the fasting MMC in a vagus-independent manner. Finally, we believe that the changes in duodenal pH triggered by flowing gastric acid and the release of duodenal bicarbonate through the involvement of PGE2-α and 5HT4 receptor are the key events in the occurrence of the MMC.

Involvement of Transient Receptor Potential Vanilloid Receptor 1, (TRPV1)-Expressing Vagal Nerve in the Inhibitory Effect of Gastric Acidification on Exogenous Motilin-Induced Gastric Phase III Contractions in Suncus murinus.

BACKGROUND: Gastric acidification inhibits motilin-induced gastric phase III contractions. However, the underlying mechanism has not been thoroughly investigated. Here, we studied the inhibitory mechanism by gastric acidification on motilin-induced contraction in Suncus murinus (S. murinus). METHODS: We measured interdigestive gastric phase III contractions in conscious, freely moving S. murinus, and examined the inhibitory effect of gastric acidification on motilin action and the involvement of the vagus nerve and transient receptor potential vanilloid receptor 1 (TRPV1) in the inhibitory mechanism. RESULTS: A bolus injection of motilin evoked phase III-like contractions during intravenous infusion of saline. Intragastric acidification (pH 1.5-2.5) inhibited motilin-induced phase III contractions in a pH-dependent manner and significantly decreased the motility index at a pH below 2.0. In contrast, intraduodenal acidification (pH 2.0) failed to inhibit motilin-induced contractions. Vagotomy significantly alleviated the suppression of motilin-induced gastric contractions under acidic conditions (pH 2.0), suggesting vagus nerve involvement. Moreover, intragastric acidification (pH 2.0) significantly increased the number of c-Fos-positive cells in the nucleus tractus solitarii. In vagotomized S. murinus, the number of c-Fos-positive cells did not change, even under gastric acidification conditions. TRPV1 mRNA was highly expressed in the muscle and mucosal regions of the antrum and the nodose ganglion, whereas was not detected in the upper small intestine. Capsazepin, a TRPV1 antagonist, completely rescued the inhibitory effect of gastric acidification. CONCLUSIONS: Gastric acidification in S. murinus inhibits motilin-induced contractions, a finding similar to results observed in humans, while TRPV1-expressing vagus nerves play a role in the inhibitory mechanism.

Enantioselective synthesis of derivatives and structure-activity relationship study in the development of NA255 as a novel host-targeting anti-HCV agent.

Hepatitis C virus (HCV) infection represents a serious health-care problem. Previously we reported the identification of NA255 from our natural products library using a HCV sub-genomic replicon cell culture system. Herein, we report how the absolute stereochemistry of NA255 was determined and an enantioselective synthetic method for NA255 derivatives was developed. The structure-activity relationship of the NA255 derivatives and rat pharmacokinetic profiles of the representative compounds are disclosed.

[Laparoscopic radical prostatectomy: six key points of operative skill for achieving better urinary continence].

Postoperative urinary incontinence is a major impairment to patients' quality of life after prostatectomy, and is not limited to laparoscopic total prostatectomy. Improvements in devices and techniques of laparoscopic surgery have facilitated reliable cancer control, and in this situation there will now be increasing focus on postoperative quality of life (QOL), particularly urinary incontinence. Between July 2007 and March 2009, we have performed laparoscopic total prostatectomy for 53 patients, focusing on techniques to reduce urinary incontinence. Here we report the details of six key points of operative skill for achieving better urinary continence. These include (1) minimal distal incision of the endopelvic fascia; (2) preservation of the bladder neck; (3) bilateral nerve-sparing surgery; (4) preservation of the puboprostatic ligament and its refixation to the anterior aspect of the bladder neck (bladder neck sling suspension); (5) preservation of the posterior (membranous) urethra; (6) suturing of the posterior aspect of the rhabdosphincter, the remaining portion of the Denonvilliers fascia, and the bladder neck (restoration of the Denonvilliers fascia). Moreover, we separated the 53 patients into two groups: those who were not treated using the above six key points, and those who were. We then compared the data for the two groups with regard to the time taken for continence recovery, operative parameters (operation time and bleeding), and postoperative pathological findings.

[Renal cell carcinoma in a horseshoe kidney: a case report].

A 59-year-old man visited another hospital with a chief complaint of malaise. Radiological examinations revealed a renal cell carcinoma associated with horseshoe kidney. He was referred to our hospital. The patient was successfully treated with open partial nephrectomy following isthmus division. Histological findings exhibited grade 2, pT1a, clear cell type, renal cell carcinoma. He is free of disease at twelve months after the operation.

[A pheochromocytoma of urinary bladder treated with neoadjuvant chemotherapy].

A 69-year-old female presented with hypertension and a solid mass in the bladder on ultrasonography. Cystoscopy revealed a submucosal tumor in the right lateral wall of the bladder. A transurethral resection was performed. Histologically, pathologic examination revealed a malignant pheochromocytoma. She refused surgical therapy and radiation therapy. She had no treatment for two years. She suddenly complained of gross hematuria. T2-weighted magnetic resonance imaging showed a bladder tumor of high intensity and extra-bladder invasion. She was treated with chemotherapy (CVD) for 26 cycles. Since the tumor size was reduced, she was referred to our hospital for operative indication. Partial cystectomy was performed. Histologically, the tumor was a pheochromocytoma of the urinary bladder. Ten months after the operation, she has no clinical evidence of recurrence.

New analogue of arenastatin A, a potent cytotoxic spongean depsipeptide, with anti-tumor activity.

Two analogues possessing steric hindered substituents on C-15 of arenastatin A (1), a potent cytotoxic spongean depsipeptide, were synthesized and shown to enhance stability in mouse serum. Notably, 15-tert-butylanalogue (6) with higher cytotoxicity exhibited in vivo anti-tumor activity through iv administration different from 1. Additionally, conformation analysis among the two analogues and arenastatin A (1) indicated that the torsion angle from C-14 to C-20 is a conclusive factor for the potent cytotoxicity of 1.