Novel spinal pathways identified by neuronal c-Fos expression after urethrogenital reflex activation in female guinea pigs

[Urethral reflexes: A review]

INTRODUCTION

The urethrosphincter complex is involved not only in maintaining urinary continence, particularly during effort, but also for the achievement of a complete and effective micturition. Indeed, the urethra is not a simple passive channel for the evacuation of urine from the bladder to the urethral meatus, since its resistive capacities and its possibilities of modulation of the micturition reflex depend on its reflex role either as a sensory afferent or as a neuro-muscular effector. It also participates in many genito-sexual and ano-rectal réflexes.

MATERIAL AND METHOD

This review of the literature describes the various reflexes of the urethra as a sensory stimulus or a neuromuscular effector. All articles referenced in this review were obtained from articles indexed on Pubmed-Medline, using the keywords: "urethral reflexes; "reflex bladder"; "urination reflex"; "intravaginal; vaginal"; "anorectal; sphincter"; "Storage and voiding"; "reflexes sneezing"; "cough reflex". Other articles were selected through references of the articles issued from the first research. Only articles in English and French have been selected. The articles concerned animal and human experiments.

RESULTS

Eight hundred and sixty-four referenced articles were founded and a total of 75 articles were included, describing the various reflexes mediated by the urethra acting as a sensory afferent or mechanical effector. We differentiated the known data in humans and animals.

CONCLUSION

The urethra is a complex anatomical structure ensuring, through numerous reflex mechanisms, urinary continence. Urethral resistances are modulated during efforts and depends on the bladder capacity and the intensity of the efforts. During micturition, the coordination between the bladder and the urethra is mediated by reflex pathways organized at the cerebral, spinal and lumbosacral levels. The modulation of the micturition in term of efficacy and velocity, is due in part, to the re-afferentation of the spinal reflex by continuous stimulus of the urethral canal. Many of these reflexes are imperfectly described. Finally, the urethra is implicated in reflex loops of anal continence and sexual functions.

Electroacupuncture for chemotherapy-induced anorexia through humoral appetite regulation: A preliminary experimental study

Chemotherapy-induced anorexia (CIA), which may lead to severe nutrition-associated problems, is a common complication associated with anti-cancer therapies. In the present study, the anti-anorexigenic effect of electroacupuncture (EA) was explored through assessing a change in appetite-associated peptides and c-Fos expression in a rat model of cisplatin-induced anorexia. In order to identify the most effective acupuncture point, 20 male Wistar rats (divided into five groups including the normal saline control, cisplatin only control and three groups according to the acupoints stimulated) were subjected to EA for 10 min at CV12, ST36 or PC6 daily for 4 days. Subsequently, the rats received intraperitoneal injections of cisplatin (6 mg/kg) to induce CIA. Food intake and reduction in body weight gain as the anorexia-associated outcomes were assessed daily for up to 3 days after cisplatin injection, and CV12 was eventually chosen as the most effective acupoint to test the anti-anorexigenic effect of EA. Furthermore, food intake, body weight and the concentrations of appetite-associated peptides, including ghrelin, cholecystokinin (CCK) and 5-hydroxytryptamine (5-HT), in addition to c-Fos expression, were comparatively assessed between the CV12 EA group (n=6; rats treated with EA at CV12 daily for 4 days) and a control group (n=6; rats without treatment). The results indicated that the CV12 EA group exhibited a better outcome regarding food intake and body weight compared with the controls. Although there was no statistically significant difference observed, the secretion of serum ghrelin and CCK was increased in the CV12 EA group compared with that in the control group. The plasma level of 5-HT after cisplatin injection in the CV12 EA group was lower compared with that in the control, although no statistical significance was reached. Although not statistically significant, the expression of c-Fos protein in the nucleus tractus solitarius (NTS) was reduced in the CV12 EA rats. In addition, the hypothalamic mRNA levels of brain-derived neurotrophic factor (BDNF) were significantly increased in the CV12 EA group. In the hypothalamus, the expression of neuropeptide Y mRNA slightly increased in the cisplatin + CV12 EA group compared with the cisplatin only control group. In conclusion, the anti-anorexigenic effect of EA on CIA may be associated with an increase in the secretion of ghrelin and CCK and a decrease in the secretion of 5-HT into the serum, a reduction of c-Fos expression in the NTS and an increase in BDNF mRNA expression in the hypothalamus.

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.