Action of naftopidil on spinal serotonergic neurotransmission for inhibition of the micturition reflex in rats

Choreito, a Kampo medicine attenuates detrusor overactivity and bladder pain symptoms in rat tranilast-induced interstitial cystitis/bladder pain syndrome-like model

AIMS

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic inflammatory condition of the bladder. However, there are only a few medicines that are of pharmaceutical grade and reliably effective for IC/BPS symptoms. Choreito (CRT) is a pharmaceutical-grade Kampo medicine and has been widely prescribed for patients of lower urinary tract symptoms (LUTS) and BPS in Japan. In this study, we exploratory investigated the effects of CRT on the IC/BPS-like symptoms induced by tranilast.

METHODS

The rat IC/BPS-like model was induced by feeding administration with 0.4% tranilast. The rats were divided into the three following treatment groups: normal diet (Normal), tranilast treatment (Control), and the groups of 1% CRT (CRT) treatment for IC/BPS-like model. After 4 weeks, continuous cystmetry, locomotor, and vascular permeability was assessed. Furthermore, the cytokine levels in bladder were analyzed by the Bio-Plex suspension array system and plasma monoamine were measured.

RESULTS

Control group exhibited 14.3% decrease of locomotor activity in the dark period, and which were 20.3% increase by 1%CRT treatment. The voiding interval was shorter in control than in other groups. 1%CRT suppressed the shortening of voiding interval. Evans blue leakage of bladder wall observed 44.8% higher in control group than in the normal group. The leakage of 1%CRT group was 33.3% less than in the control group. The cytokine level of IFNγ and VEGF were elevated in the control, and CRT treatment suppressed the elevation of IFNγ in the bladder. Plasma noradrenaline was significantly reduced by CRT treatment compared normal group.

CONCLUSION

These results suggest that CRT can be an effective therapeutic agent for the treatment of IC/BPS-like symptoms.

Central pattern generators in the brainstem and spinal cord: an overview of basic principles, similarities and differences

Central pattern generators (CPGs) are generally defined as networks of neurons capable of enabling the production of central commands, specifically controlling stereotyped, rhythmic motor behaviors. Several CPGs localized in brainstem and spinal cord areas have been shown to underlie the expression of complex behaviors such as deglutition, mastication, respiration, defecation, micturition, ejaculation, and locomotion. Their pivotal roles have clearly been demonstrated although their organization and cellular properties remain incompletely characterized. In recent years, insightful findings about CPGs have been made mainly because (1) several complementary animal models were developed; (2) these models enabled a wide variety of techniques to be used and, hence, a plethora of characteristics to be discovered; and (3) organizations, functions, and cell properties across all models and species studied thus far were generally found to be well-preserved phylogenetically. This article aims at providing an overview for non-experts of the most important findings made on CPGs in in vivo animal models, in vitro preparations from invertebrate and vertebrate species as well as in primates. Data about CPG functions, adaptation, organization, and cellular properties will be summarized with a special attention paid to the network for locomotion given its advanced level of characterization compared with some of the other CPGs. Similarities and differences between these networks will also be highlighted.

α1 -Blocker inhibits non-voiding contractions and decreases the level of intravesical prostaglandin E2 in rats with partial bladder outlet obstruction

OBJECTIVES

To elucidate the mechanism of action of the α₁ -blocker, naftopidil, in partial bladder outlet obstruction animals, by studying non-voiding contractions, and the levels of mediators were measured with resiniferatoxin treatment.

METHODS

A total of 35 female Wistar rats were randomly divided into a sham or bladder outlet obstruction group, and rats in each group were given vehicle or resiniferatoxin. Incomplete urethral ligation was applied to the bladder outlet obstruction group. After cystometry, the intravesical level of prostaglandin E₂ and adenosine 5'-triphosphate was measured in the instilled perfusate collected. Naftopidil was given at the time of cystometry.

RESULTS

In bladder outlet obstruction rats, non-voiding contractions, bladder capacity, and the intravesical levels of prostaglandin E₂ and adenosine 5'-triphosphate were markedly increased compared with sham rats. Naftopidil decreased non-voiding contractions, enlarged the bladder capacity, and decreased the intravesical levels of prostaglandin E₂ and adenosine 5'-triphosphate. Resiniferatoxin enhanced non-voiding contractions. The effects of naftopidil on non-voiding contractions and the intravesical level of prostaglandin E₂ , but not adenosine 5'-triphosphate, were tolerant to resiniferatoxin.

CONCLUSIONS

In bladder outlet obstruction rats, one cause of generation of non-voiding contractions might be bladder wall distension, but not transient receptor potential cation channel V1. The increase in intravesical prostaglandin E₂ might also be associated with the generation of non-voiding contractions. Naftopidil inhibits the increase in non-voiding contractions and decreases the intravesical level of prostaglandin E₂ , which are independent of transient receptor potential cation channel V1.