Effects of Gegen (Puerariae lobatae Radix) water extract on improving detrusor overactivity in spontaneously hypertensive rats.

AIM: Ex vivo experiments showed that the water extract of Puerariae lobatae Radix (named Gegen in Chinese) induced detrusor relaxation. The aim of this study was to prove the in vivo efficacy of Gegen on improving detrusor overactivity and its possible synergism with darifenacin (a first-line muscarinic receptor-3 inhibitor) in spontaneously hypertensive rats (SHR), a rat model exhibiting symptoms of detrusor overactivity. METHOD: After daily oral administration of Gegen 30 (Gegen, 30mg/kg); Gegen 300 (Gegen, 300mg/kg); Low_Dar (darifenacin, 3mg/kg); High_Dar (darifenacin, 30mg/kg) Low_Dar+Gegen 30 or High_Dar+Gegen 30 for 3 weeks, bladder detrusor strips of the rats were isolated and assessed with different stimulators for the measurement of tonic and phasic contractile activities (including phasic amplitude and frequency). Modes of stimulation included the use of carbachol, isoprenaline and electrical field stimulation (EFS). RESULTS: All drug treatments significantly reduced carbachol-stimulated tonic contractile activities, but did not change the phasic amplitude. Meanwhile, the treatments with Gegen 300; Low_Dar; Low_Dar+Gegen 30; and High_Dar+Gegen 30 decreased carbachol-stimulated phasic frequency. Gegen 300 and Low_Dar+Gegen 30 showed stronger potency on lowering EFS-induced responses. Under isoprenaline-induced relaxation, only Gegen 300 significantly enhanced this relaxation by decreasing tonic contraction; Gegen 300; Low_Dar; Low_Dar+Gegen 30; and High_Dar+Gegen 30 increased the reduction of phasic frequency, but all treatment did not alter their phasic amplitude. Combination Index (CI) showed that the combination with Low_Dar and Gegen 30 had very strong synergism (CI <0.1) on inhibiting EFS-induced contractile response. CONCLUSION: Gegen improved detrusor overactivity through neurogenic and anti-muscarinic mechanisms. Gegen and darifenacin together attained synergism for detrusor overactivity treatment via the neurogenic pathway.

Bilateral Common Carotid Artery Occlusion in Spontaneously Hypertensive Rats: A Feasible Animal Model for Ocular Ischemic Syndrome.

The purpose of this study was to investigate the feasibility of inducing ocular ischemic syndrome in spontaneously hypertensive rats. Hypertensive and normotensive Wistar-Kyoto rats had bilateral occlusion or sham surgery. They were divided into 4 groups: (1) hypertensive-ischemia, (2) hypertensive-sham, (3) normotensive-ischemia, and (4) normotensive-sham. Four months after the operation, the global changes of the eye and pupillary light reflex were assessed. Then each rat was perfused, and randomly one of the bulbuses oculi was prepared as retinal flat mounts for investigation of vascular changes. The opposite eyeball was prepared as a paraffin section for observation of the linear density of retinal ganglion cells and for thickness measurement. One hypertensive-ischemia rat had a cataract in one eye and another rat in the same group had bulbus oculi collapse in one eye. The light reflex disappeared in 13.33% of hypertensive-ischemia rats, and the rest of the hypertensive-ischemia rats and normotensive-ischemia rats had slow reflex. Compared with the respective controls, the peripheral retinal vascular network in hypertensive-ischemia and normotensive-ischemia rats was sparse; linear density of the retinal ganglion cells was significantly reduced; and the retinal thickness was reduced. Compared with normotensive-ischemia rats, the hypertensive-ischemia rats demonstrated more severe changes. After bilateral common carotic artery occlusion, the eyes of hypertensive rats developed various pathological changes similar to those of ocular ischemic syndrome. In conclusion, an animal model for ocular ischemic syndrome can be created by bilateral common carotid artery occlusion in spontaneously hypertensive rats. Anat Rec, 299:806-814, 2016. © 2016 Wiley Periodicals, Inc.

Short-Term Flavoxate Treatment Alters Detrusor Contractility Characteristics: Renewed Interest in Clinical Use?

OBJECTIVES: Flavoxate has had a long history of use in the treatment of overactive bladder, despite the lack of documentation on its clinical efficacy and mechanism(s) of action. This study was conducted to understand how contractility characteristics of the detrusor are affected after a short period of flavoxate treatment. METHODS: Eight-week-old mice were treated with flavoxate for 5 days and detrusor contractile responses were examined ex vivo under different pharmacological and electrical stimuli. RESULTS: K(+) -Krebs'-induced contraction developed more slowly while 64 Hz electrical field stimulation-induced contraction developed faster in flavoxate-treated strips when compared to control. Amplitudes of maximal and steady-state contraction induced by 3 µmol/L carbachol were also larger after flavoxate treatment. Control strips showed an overall greater dependence on stimulus strength in eliciting the responses. CONCLUSIONS: These findings provided new information of how short-term flavoxate treatment altered contractility characteristics at the bladder level, which may instill new interest in investigating the use of this drug in bladder disorders not responding well to conventional treatments.

Comparison of Two Old Phytochemicals versus Two Newly Researched Plant-Derived Compounds: Potential for Brain and Other Relevant Ailments.

Among hundreds of formulae of Chinese herbal prescriptions and recently extracted active components from the herbs, some of which had demonstrated their functions on nervous system. For the last decade or more, Gingko biloba and Polygala tenuifolia were widely studied for their beneficial effects against damage to the brain. Two compounds extracted from Apium graveolens and Rhizoma coptidis, butylphthalide and berberine, respectively, received much attention recently as potential neuroprotective agents. In this review, the two traditionally used herbs and the two relatively new compounds will be discussed with regard to their potential advantages in alleviating brain and other relevant ailments.

Indispensable value of clinical trials in the modernization of traditional Chinese medicine: 12 years' experience at CUHK and future perspectives.

The last decade has seen a wealth of information reporting the beneficial effects of Chinese herbal medicines. While a lot more studies were done using in vitro and in vivo research platforms, much fewer investigations were conducted according to evidence-based requirements in clinical settings. The Institute of Chinese Medicine at the Chinese University of Hong Kong (CUHK) has had the opportunity to collaborate with clinicians over the years to initiate and conduct dozens of clinical trials investigating and verifying the therapeutic values of Chinese herbs in selected disease conditions. Of the many disorders, we chose to focus on those that are known for their difficulties achieving perfect results with conventional treatment methods. Examples include non-healing ulcers, allergic conditions, degenerative diseases and cancer. Protective effects of the herbs in such chronic diseases as coronary artery disease and osteoporosis were also part of our focus. Even in healthy individuals and those recovering from chemotherapy, Chinese herbs could help with the immune system and were studied in our clinical trials as well. This paper aims to highlight the important findings from these clinical studies while at the same time, stressing the indispensable value of clinical trials in modernizing the use of Chinese herbs in present-day medicine.

Chronic ketamine treatment-induced changes in contractility characteristics of the mouse detrusor.

PURPOSE: To understand bladder contractility changes induced by chronic ketamine treatment, noting the prevalence of its abuse worldwide. METHODS: A mouse model of chronic ketamine treatment was used and detrusor strip contractility was measured. Rising and falling phases of contractile responses as well as maximal, average sustained and phasic contractions were measured. RESULTS: While maximal contractility of ketamine-treated strips was identical to the saline controls, the former displayed slower contraction rates under K(+)-Krebs, carbachol and electrical stimulation. The decay phase of electrically stimulated responses was also slower at most stimulation frequencies in the ketamine-treated strips. Greater sensitivity to varying the strengths of stimuli was observed in the ketamine-treated strips. CONCLUSIONS: Altered contractility characteristics of the bladder after chronic ketamine treatment were revealed, which could potentially be useful in the development of improved treatment regimens.

Low concentrations of niflumic acid enhance basal spontaneous and carbachol-induced contractions of the detrusor.

PURPOSE: The urinary bladder expresses Ca(2+)-activated Cl(-) channels (CACC), but its physiological role in governing contractility remains to be defined. The CACC modulator niflumic acid (NFA) is widely used despite the variable results arisen from different drug concentrations used. This study was designed to examine the effects of NFA at low concentrations on detrusor strip contractility. METHODS: Rat detrusor strips with mucosa-intact (+MU) and mucosa-denuded (-MU) were prepared in transverse (Tr) and longitudinal (Lg) with respect to the bladder orientation. Isometric force measurements were made at baseline (for spontaneous phasic contractile activity) and during drug stimulation (by carbachol, CCh) with and without NFA. RESULTS: NFA (1 and 10 µmol/L) pretreatment enhanced CCh-induced contractions more in +MU than -MU strips with no selectivity on contractile direction. For spontaneous phasic contractions, NFA-treated strips in the Tr direction showed increased phasic amplitude, while phasic frequency was unchanged. CONCLUSIONS: The findings suggest low concentrations of NFA having a potentiating effect on detrusor contractions that was sensitive to the MU and contractile direction.

Current Evidence of Chinese Herbal Constituents with Effects on NMDA Receptor Blockade.

NMDA receptor (NMDA-R) is an important molecular entity governing a wide range of functions in the central nervous system. For example, the NMDA-R is involved in memory and cognition, and impairment of both (as in Alzheimer's Disease) is attributed to NMDA-mediated neurotoxicity. With greater understanding of the NMDA-R structure, antagonists with varying degrees of binding-site and subtype selectivity have been developed and put into clinical use. Discovery of target-specific Chinese herbs have also been made in parallel. This article provides an overview of the known active sites on the NMDA-R, followed by a discussion of the relevant herbs and their constituents. Experimental evidence supporting the inhibitory role of the herbal compounds on the NMDA-R is highlighted. For some of the compounds, potential research directions are also proposed to further elucidate the underlying mechanisms of the herbs. It is envisaged that future investigations based on the present data will allow more clinically relevant herbs to be identified.

Greater brain volumes are activated when performing simple calculating tasks in persons accustomed to lower altitudes than those to higher altitudes.

Chronic exposure to a hypoxic environment results in a number of physiological changes such as cardiac arrhythmia and pulmonary edema. We hereby studied the variations in activation of brain areas during simple calculation tasks between individuals originating from different altitudes. Two groups of subjects, one from 1700 m above sea level (lowlanders) and the other one from at least 3000 m above sea level (highlanders), performed a simple calculation task by heart. The fMRI were taken and horizontal, sagittal, and coronal sections were analyzed to identify activated brain areas. Both lowlanders and highlanders performed the calculation task successfully. Horizontal sections revealed similar activated areas in the deep and anterior part of the right parietal lobe of both lowlanders and highlanders. In the highlanders, coronal and sagittal sections showed lower activities. Smaller brain volumes were activated in the highlanders as shown by the computer brain templates, with fewer total voxels recorded than in the lowlanders (P = 0.003). Computerized comparison of overall active brain regions between lowlanders and highlanders also revealed that smaller brain regions were activated. The results showed that while all subjects completed the task successfully, the highlanders did so using smaller brain regions than the lowlanders.

Variations in carbachol- and ATP-induced contractions of the rat detrusor: effects of gender, mucosa and contractile direction.

PURPOSE: Contractile characteristics of the bladder may depend on variables such as gender, mucosa (MU) and direction of the contractions. However, definitive information is not yet available despite earlier studies on the effects of one variable or another. Here, we explored the differences in the rat detrusor attributable to gender, mucosa and contractile direction. METHODS: K+, carbachol (CCh) and ATP were used as contractile stimuli on rat detrusor strips with and without MU. Contractility was monitored using a myograph system. Both tonic and phasic contractile activities were analyzed. RESULTS: MU-independent contractions induced by CCh were more potent in females, an effect specific to the longitudinal direction only. The maximal CCh response was larger also in females when MU was removed, suggesting a stronger MU-independent component in the contraction. The larger area under curves of the females under ATP stimulation showed dependence on MU and contractile direction as well. ATP-induced contractions in the males were affected more by MU in the transverse direction than in the females. Direction- and MU-dependent variability of ATP responses was also observed in the males but not in females. CONCLUSIONS: Findings here added new information to the understanding of bladder contractile physiology, providing insights into the quest for better drugs in managing bladder disorders.

Inhibitory effects of salviae miltiorrhizae radix (danshen) and puerariae lobatae radix (gegen) in carbachol-induced rat detrusor smooth muscle contractility.

Both danshen (D) and gegen (G) have proven relaxant effects on vascular smooth muscle, thus their potential bladder inhibitory effects have impending interests in urology. The aim of this study was to demonstrate the novel effects of D and G on detrusor smooth muscle contractility. Urothelium-intact (+UE) and urothelium-denuded (-UE) detrusor strips were isolated from the rat. Isometric tension was measured using a myograph system. Carbachol (CCh) was used to pre-contract the detrusor strips prior to stepwise relaxation by adding extracts of D, G, and a DG (7:3) formulation. Tonic relaxation level and phasic contractile activity under the herbal treatments were analyzed. There was no difference in the herbal effects between +UE and -UE strips. D alone induced a much smaller relaxation than G alone or DG. G alone also suppressed phasic amplitude but not phasic frequency while DG suppressed both parameters. D and G acted synergistically to yield the observed effects on detrusor smooth muscle. The findings showed that the DG formulation were able to relax the detrusor as well as suppress phasic contractions, both actions important in maintaining normal bladder filling and urine storage processes. Hence DG may have new application in the management of bladder disorders.

Gastrodia elata decreases isoprenaline potency and enhances spontaneous phasic activity in the rat detrusor.

Gastrodia elata (Tianma) is a traditional Chinese herb with demonstrated vasodilatory effects. This pilot study examined the effects of Tianma treatment on bladder smooth muscle contractility. Rats were treated with 2.5 g Tianma per kg body weight over 7 weeks. Contractility was measured in detrusor strips isolated in both transverse (Tr) and longitudinal (Lg) directions with the urothelium intact (+UE) or denuded (-UE). Spontaneous phasic activity was enhanced in longitudinal +UE strips. No differences between control and Tianma-treated detrusor strips were detected in contractions elicited by K+-Krebs' solution or carbachol. Isoprenaline (IPNA)-induced relaxation remained unchanged in -UE strips after Tianma treatment. However, potency of IPNA was lower in Tianma-treated +UE strips in the longitudinal direction. These findings provided an initial assessment of how Tianma altered bladder smooth muscle function. It will be of interest in future investigations to elucidate the mechanisms via which Tianma exerts its actions on the bladder.

Urothelium-dependent and urothelium-independent detrusor contractility mediated by nitric oxide synthase and cyclooxygenase inhibition.

AIMS: The urothelium has been implicated in regulating detrusor smooth muscle contractility but the identity of the putative urothelium-derived inhibitory factor remains unconfirmed. There was inconclusive evidence on the role of nitric oxide synthase (NOS) and cyclooxygenase (COX) in mediating detrusor contractions. This study examined varying regulation by NOS and COX in transverse and longitudinal carbachol (CCh)-induced and unstimulated phasic contractions. METHODS: Rat detrusor strips with the urothelium-intact (+UE) and urothelium-denuded (-UE) were isolated in both transverse and longitudinal directions. Isometric tension of the detrusor strips was recorded both during stimulation with CCh and at the unstimulated state. In the unstimulated state, phasic contractile activity was measured. Tension recordings were made with and without the NOS inhibitor N(ω)-nitro-L-arginine methyl ester (L-NAME) and COX inhibitor indomethacin (Indo). RESULTS: Only transverse +UE strips responded convincingly to L-NAME and Indo treatment, generating larger CCh-induced contractions. In unstimulated tissues, L-NAME treatment increased phasic amplitude in -UE strips only. Indo treatment failed to elicit any change in the amplitude but suppressed frequency of the phasic activity in transverse +UE strips. There was no significant Indo-mediated change in other strips. CONCLUSIONS: The data suggested heterogeneity in the regulation of directional detrusor contractility via NOS- and COX-associated mechanisms.

Bladder contractility is mediated by different K+ channels in the urothelium and detrusor smooth muscle.

The roles played by K(+) channels in the urothelium (UE) and detrusor smooth muscle (DSM) in regulating agonist-induced bladder contraction is not known at present. Thus, the effects in carbachol (CCh)-induced contraction in UE-intact (+UE) and UE-denuded (-UE) rat detrusor strips pretreated with K(+)-channel blockers were investigated here. The K(+)-channel blockers used were 4-aminopyridine (4-AP), glibenclamide (Glib), iberiotoxin (IbTx), charybdotoxin (ChTx), and apamin. In the absence of K(+)-channel blockers, control CCh-induced contractions were more potent in -UE than +UE strips. Treatment with IbTx and apamin resulted in more potent CCh-induced contractions in +UE strips. In -UE strips, CCh potency was increased by ChTx and Glib, but decreased by 4-AP. Different K(+) channels in the UE and DSM were thus involved in regulating bladder contractions. Contractile mediatory function of these channels, specific to the UE or DSM, may be potential drug targets in the management of bladder disorders.

ß-Adrenoceptor-mediated differences in transverse and longitudinal strips from the rat detrusor.

Contractions and relaxations of the urinary bladder occur in all directions to facilitate urine release and storage. Transverse and longitudinal contractility of detrusor smooth muscle have been studied before using various pharmacologic stimuli but not ß agonists. Given the importance of ß-adrenoceptors in mediating bladder relaxation, the effects of isoprenaline (IPNA) in transverse and longitudinal contractility were examined. Pretreatment with a low concentration of IPNA (0.1 or 1 µM) suppressed carbachol (CCh)-induced contractions, more in the transverse than longitudinal direction. Increasing the IPNA concentration to 10 or 100 µM resulted in greater inhibition of longitudinal contractions. Also in the longitudinal direction, IPNA-induced relaxation was greater than in the transverse direction. When precontracted with a submaximal concentration of CCh (1 µM), IPNA increased the phasic activity in the longitudinal direction only. In summary, ß-adrenoceptor-mediated differences between transverse and longitudinal contractility were revealed. In testing the relaxant properties of selective ß-agonists, the findings here should be considered such that other than the conventional longitudinal contractions, measurements are also made in other directions.

Bladder Contractility Is Mediated by Different K+ Channels in the Urothelium and Detrusor Smooth Muscle.

The roles played by K+ channels in the urothelium (UE) and detrusor smooth muscle (DSM) in regulating agonist-induced bladder contraction is not known at present. Thus, the effects in carbachol (CCh)-induced contraction in UE-intact (+UE) and UE-denuded (-UE) rat detrusor strips pretreated with K+-channel blockers were investigated here. The K+-channel blockers used were 4-aminopyridine (4-AP), glibenclamide (Glib), iberiotoxin (IbTx), charybdotoxin (ChTx), and apamin. In the absence of K+-channel blockers, control CCh-induced contractions were more potent in -UE than +UE strips. Treatment with IbTx and apamin resulted in more potent CCh-induced contractions in +UE strips. In -UE strips, CCh potency was increased by ChTx and Glib, but decreased by 4-AP. Different K+ channels in the UE and DSM were thus involved in regulating bladder contractions. Contractile mediatory function of these channels, specific to the UE or DSM, may be potential drug targets in the management of bladder disorders.

The role of the urothelium and ATP in mediating detrusor smooth muscle contractility.

OBJECTIVES: To examine the contractility of urothelium-intact (+UE) and urothelium-denuded (-UE) rat detrusor strips under adenosine triphosphate (ATP) treatment. Purinergic signaling exists in the bladder but both the inhibitory effect of ATP on detrusor contractions and the function of urothelial ATP are not established. METHODS: Detrusor strips were obtained from bladders of young adult rats. Isometric tension from both transverse and longitudinal contractions was measured using a myograph. The muscarinic agonist carbachol (CCh) was used to induce contractions, which were under the influences of different concentrations of ATP. RESULTS: In both +UE and -UE strips, 1 mM ATP suppressed CCh-induced contractions. In longitudinal contractions, ATP added to the inhibitory effect of urothelium on CCh responses. Removal of the urothelium, but with exogenous ATP added, recovered the CCh responses to the same level as in +UE strips with no added ATP. Transverse contractions were less susceptible to ATP in the presence of urothelium. CONCLUSIONS: We showed that the urothelium and ATP suppressed CCh-induced contractions to a similar extent. The findings suggest an inhibitory role of urothelial ATP in mediating detrusor smooth muscle contractility, which may be impaired in diseased bladders.

Teaching the modes of Ca2+ transport between the plasma membrane and endoplasmic reticulum using a classic paper by Kwan et al.

This teaching article uses the report by Kwan et al., "Effects of methacholine, thapsigargin, and La(3+) on plasmalemmal and intracellular Ca(2+) transport in lacrimal acinar cells," where the effects of Ca(2+)-mobilizing agents in regulating Ca(2+) fluxes were examined under various conditions. Upper-level undergraduate and new graduate students in physiology are the targe audience. Teaching and learning points are put forth in this article to illustrate 1) the characteristics of methacholine- and thapsigargin-induced Ca(2+) responses, 2) the different endoplasmic reticulum Ca(2+) stores accessible to methacholine and thapsigargin, 3) the inhibitory effects of La(3+) on Ca(2+) extrusion and Ca(2+) influx, and 4) the facilitatory role of La(3+) on endoplasmic reticulum Ca(2+) recycling. Each of the above concepts is first explained with references to the figures adapted from the original article. A list of student learning questions then follows, where the answers are found in the teaching notes for the instructors. It is the objective of this article to make both teaching and learning Ca(2+) regulation a rewarding experience for all.

Blockade of voltage-sensitive K+ channels increases contractility more in transverse than in longitudinal rat detrusor strips.

OBJECTIVES: To investigate the effects of voltage-sensitive K(+) channel blockade on phasic contractions in transverse (TR) and longitudinal (LO) rat detrusor strips. The contractility of LO detrusor strips has been studied more extensively than that of TR ones, with the latter hardly used in experiments. Phasic contractions, regulated by various types of K(+) channels, are present in normal bladders and are more commonly seen in diseased bladders. METHODS: Contractility was measured in TR and LO detrusor strips from young adult rats. Concentration-response curves of tetraethylammonium and 4-aminopyridine (4-AP) were constructed. Both the mean developed tension and the cyclic height of the phasic contractions were determined. RESULTS: At > or = 10(-2) mol/L, tetraethylammonium increased the developed tension and amplitude of the phasic contractions without differences between the TR and LO strips. 4-AP also increased the developed tension and amplitude of the phasic contractions but with greater effects in the TR than in the LO strips. At a maximal 4-AP concentration (10(-2) mol/L), the mean developed tension was 52.96% +/- 6.39% in the TR strips and 28.88% +/- 5.91% in the LO strips. The amplitude of the phasic contractions was 11.07% +/- 2.78% for the TR strips and 3.15% +/- 1.31% for the LO strips. CONCLUSIONS: Both nonselective K(+) channel blockade by tetraethylammonium and selective voltage-sensitive K(+) channel blockade by 4-AP resulted in increased contractions in LO and TR strips; however, the latter displayed greater effects only with 4-AP treatment. Thus, measuring detrusor contractions in different orientations might reveal heterogeneous responses that are dependent on the pharmacologic stimulus.