Discovery of mesoscopic nematicity wave in iron-based superconductors

[Figure: see text].

Pressure-induced reconstitution of Fermi surfaces and spin fluctuations in S-substituted FeSe

FeSe is a unique high-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$T_c$$\end{document}Tc iron-based superconductor in which nematicity, superconductivity, and magnetism are entangled with each other in the P-T phase diagram. We performed \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{77}$$\end{document}77Se-nuclear magnetic resonance measurements under pressures of up to 3.9 GPa on 12% S-substituted FeSe, in which the complex overlap between the nematicity and magnetism are resolved. A pressure-induced Lifshitz transition was observed at 1.0 GPa as an anomaly of the density of states and as double superconducting (SC) domes accompanied by different types of antiferromagnetic (AF) fluctuations. The low-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$T_{\mathrm{c}}$$\end{document}Tc SC dome below 1 GPa is accompanied by strong AF fluctuations, whereas the high-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$T_{\mathrm{c}}$$\end{document}Tc SC dome develops above 1 GPa, where AF fluctuations are fairly weak. These results suggest the importance of the \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$d_{xy}$$\end{document}dxy orbital and its intra-orbital coupling for the high-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$T_{\mathrm{c}}$$\end{document}Tc superconductivity.

High-T_{c} Superconductivity in FeSe at High Pressure: Dominant Hole Carriers and Enhanced Spin Fluctuations

The importance of electron-hole interband interactions is widely acknowledged for iron-pnictide superconductors with high transition temperatures (T_{c}). However, the absence of hole pockets near the Fermi level of the iron-selenide (FeSe) derived high-T_{c} superconductors raises a fundamental question of whether iron pnictides and chalcogenides have different pairing mechanisms. Here, we study the properties of electronic structure in the high-T_{c} phase induced by pressure in bulk FeSe from magnetotransport measurements and first-principles calculations. With increasing pressure, the low-T_{c} superconducting phase transforms into the high-T_{c} phase, where we find the normal-state Hall resistivity changes sign from negative to positive, demonstrating dominant hole carriers in contrast to other FeSe-derived high-T_{c} systems. Moreover, the Hall coefficient is enlarged and the magnetoresistance exhibits anomalous scaling behaviors, evidencing strongly enhanced interband spin fluctuations in the high-T_{c} phase. These results in FeSe highlight similarities with high-T_{c} phases of iron pnictides, constituting a step toward a unified understanding of iron-based superconductivity.

Anisotropy of the superconducting gap in the iron-based superconductor BaFe2(As(1-x)P(x))2

We report peculiar momentum-dependent anisotropy in the superconducting gap observed by angle-resolved photoemission spectroscopy in BaFe₂(As_1-xP_x)₂ (x = 0.30, T_c = 30 K). Strongly anisotropic gap has been found only in the electron Fermi surface while the gap on the entire hole Fermi surfaces are nearly isotropic. These results are inconsistent with horizontal nodes but are consistent with modified s_± gap with nodal loops. We have shown that the complicated gap modulation can be theoretically reproduced by considering both spin and orbital fluctuations.

Detection of antiferromagnetic ordering in heavily doped LaFeAsO(1-x)H(x) pnictide superconductors using nuclear-magnetic-resonance techniques

We studied double superconducting (SC) domes in LaFeAsO(1-x)H(x) by using 75As and 1H nuclear-magnetic-resonance techniques and unexpectedly discovered that a new antiferromagnetic (AF) phase follows the double SC domes on further H doping, forming a symmetric alignment of AF and SC phases in the electronic phase diagram. We demonstrated that the new AF ordering originates from the nesting between electron pockets, unlike the nesting between electron and hole pockets, as seen in the majority of undoped pnictides. The new AF ordering is derived from the features common to high-Tc pnictides; however, it has not been reported so far for other high-Tc pnictides because of their poor electron doping capability.

Effect of nicotine on the pelvic afferent nerve activity and bladder pressure in rats

OBJECTIVES

To record afferent nerve activity and bladder pressure in anesthetized male rats and to investigate whether increased afferent nerve activity induced by nicotine is able to evoke reflex bladder contractions.

METHODS

Using continuous infusion cystometrography, bladder pressure was measured via a bladder cannula. Afferent activity was recorded in the uncut L6 dorsal root. Nicotine was injected intra-arterially through a cannula placed near the bifurcation of the internal iliac artery a few minutes after micturition.

RESULTS

Nicotine (0.15-1.5 micromol) evoked a marked elevation of afferent discharge without a simultaneous increase in bladder pressure. Bladder contractions appeared about 43 and 19 s after bolus injection of nicotine at 0.45 and 1.5 micromol, respectively. Firing rates of afferent nerves were reduced when the contraction appeared. Continuous infusion of nicotine at 0.75 micromol/min for 20 min evoked marked elevation of afferent discharge, which was maintained during infusion of nicotine and after it had been withdrawn. Repetitive contractions were observed thereafter and disappeared when the L6 dorsal roots were bilaterally resected.

CONCLUSIONS

A transient increase in afferent discharges induced by bolus injection of nicotine was unable to evoke reflex bladder contraction. Repetitive bladder contractions after withdrawal of continuous nicotine infusion were induced in a reflex manner by the increased afferent activity.

Intrinsic spin Hall Effect in the s-wave superconducting state: analysis of the Rashba model

A general expression for spin Hall conductivity (SHC) in the s-wave superconducting state at finite temperatures is derived. Based on the expression, we study SHC in a two-dimensional electron gas model in the presence of Rashba spin-orbit interaction (SOI). SHC is zero in the normal state, whereas it takes a large negative value as soon as the superconductivity occurs, due to the change in the quasiparticle contributions. Since this remarkable behavior is independent of the strength of the SOI, it will be widely observed in thin films of superconductors with surface-induced Rashba SOI, or in various noncentrosymmetric superconductors.

Giant orbital Hall effect in transition metals: origin of large spin and anomalous Hall effects

In transition metals and their compounds, the orbital degrees of freedom gives rise to an orbital current, in addition to the ordinary spin and charge currents. We reveal that considerably large spin and anomalous Hall effects observed in transition metals originate from an orbital Hall effect (OHE). To elucidate the origin of these novel Hall effects, a simple periodic s-d hybridization model is proposed as a generic model. The giant positive OHE originates from the orbital Aharonov-Bohm phase factor, and induces spin Hall conductivity that is proportional to the spin-orbit polarization at the Fermi level, which is positive (negative) in metals with more than (less than) half filling.

Giant intrinsic spin and orbital hall effects in Sr2MO4 (M=Ru, Rh, Mo)

We investigate the intrinsic spin Hall conductivity (SHC) and the d-orbital Hall conductivity (OHC) in metallic d-electron systems, by focusing on the t2g-orbital tight-binding model for Sr2MO4 (M=Ru, Rh, Mo). The conductivities obtained are one or 2 orders of magnitude larger than predicted values for p-type semiconductors with approximately 5% hole doping. The origin of these giant Hall effects is the "effective Aharonov-Bohm phase" that is induced by the d-atomic angular momentum in connection with the spin-orbit interaction and the interorbital hopping integrals. The huge SHC and OHC generated by this mechanism are expected to be ubiquitous in multiorbital transition metal compounds, which opens the possibility of realizing spintronics as well as "orbitronics" devices.

Adsorption of bile acid by chitosan salts prepared with cinnamic acid and analogue compounds

A chitosan (CS) powder treated with cinnamic acid and an analogue compound (CN) was prepared as CS-CN. Using it, bile acid adsorption by CS-CN and the release of CN were investigated in vitro. When CS-CN was soaked in a taurocholate solution, it released CN and simultaneously adsorbed the bile acid. For CS-CN prepared with cinnamic acid, the amount of CN released was 0.286 +/- 0.001 mmol/g CS-CN; the amount of taurocholate adsorbed was 0.284 +/- 0.003 mmol/g CS-CN. These two functions were recognized on alginate or pectin gel beads containing CS-CN. The amount of released CN was altered extensively by the species of CN used for gel-bead preparation. Results suggest that CS-CN is a candidate for complementary medicine to prevent lifestyle-related diseases.

Comparison of the effects of percutaneous and intraduodenal administration of oxybutynin on bladder contraction and salivation in rabbits

AIM

As only a few basic animal experiments have assessed the usefulness of percutaneous application of oxybutynin, we compared the effects of percutaneous application and intraduodenal injection of oxybutynin on urinary bladder contraction accompanied by micturition in conscious rabbits and salivation in anesthetized rabbits.

METHODS

Bladder contractions were induced by continuous infusion of saline (2 mL/min) into the bladder. Salivary secretion was induced by pilocarpine (0.1 mg/kg, i.v.). Oxybutynin was administered at 15 mg/animal, and the plasma concentrations of oxybutynin and N-desethyloxybutynin were measured by high-performance liquid chromatography to clarify the effective concentration.

RESULTS

The intercontraction interval (ICI) was prolonged from 0.5 h after intraduodenal injection of oxybutynin, and this effect continued for 2 h. The ICI prolongation after percutaneous application of oxybutynin appeared at 2 h and continued throughout the 6-h experimental period. The saliva secretion induced by pilocarpine was inhibited to almost the same level by oxybutynin 3 h after intraduodenal injection and 6 h after percutaneous application. However, the sum of the plasma concentrations of oxybutynin and N-desethyloxybutynin rose steeply to a very high level within 20 min after oral administration instead of intraduodenal injection and decreased within 3 h to about half of the level evident 6 h after percutaneous application.

CONCLUSION

We confirmed that percutaneous application of oxybutynin caused long-lasting ICI prolongation in our rabbit model, as compared with that after intraduodenal injection, and produced weaker inhibitory effects on saliva secretion because it did not cause steep elevation of the plasma concentration.

Central Muscarinic Receptor Subtypes Regulating Voiding in Rats

PURPOSE

Muscarinic receptors are distributed widely in the brain. A recent study revealed that central muscarinic receptors are involved in voiding regulation. However, to our knowledge the role of each muscarinic receptor subtype has not been resolved. Therefore, we evaluated the effect of intracerebroventricular administration of selective muscarinic M1 to M4 receptor antagonists on voiding function in rats.

MATERIALS AND METHODS

Female Sprague-Dawley rats were cannulated for intracerebroventricular infusion under halothane anesthesia. In experiment 1 cystometry was performed in conscious rats, and BC and maximal voiding pressure were measured. In experiment 2 a catheter was inserted via the bladder dome to the bladder neck and UPP was measured by saline infusion. Repeat cystostomy was performed, and saline infusion and discharge saline, BC, maximal IVP and minimal UPP were measured in conscious rats. Pirenzepine, methoctramine, pFHHSiD and MT-3 were used as selective M1, M2, M3 and M4 muscarinic receptor antagonists, respectively, which were injected intracerebroventricularly.

RESULTS

In experiment 1 pirenzepine and pFHHSiD increased BC and decreased maximal voiding pressure. Methoctramine and MT-3 decreased BC. In experiment 2 pirenzepine and pFHHSiD increased BC and minimal UPP, and decreased maximal IVP. Methoctramine and MT-3 decreased BC and maximal IVP. Minimal UPP remained unchanged.

CONCLUSIONS

Intracerebroventricular administration of muscarinic M1 and M3 receptor antagonists inhibited urination in conscious rats, while M2 and M4 receptor antagonists induced excitatory changes.

A method for producing overactive bladder in the rat and investigation of the effects of GABAergic receptor agonists and glutamatergic receptor antagonists on the cystometrogram

PURPOSE

We induced radio frequency (RF) lesions in the neuronal pathway leading from the forebrain to the pontine micturition center (PMC) to produce a rat model of bladder overactivity. We studied the effects of gamma-aminobutyric acid agonists (diazepam and baclofen) and glutamate receptor antagonists (MK-801 maleate and GYKI52466 [1-(4-aminophenyl-D-4-methyl-7,8 methylenedioxy-5H-2,3-benzodiazepine] hydrochloride) on the cystometrogram and developed a possible explanation of the neuronal mechanisms underlying RF lesion induced bladder overactivity.

MATERIALS AND METHOD

Seven-week-old male Sprague-Dawley rats were anesthetized with sodium pentobarbital and RF lesions were produced in the nuclei basalis. Five days later bladder contractions were induced by infusing fluid into the bladder and cystometrograms were measured in conscious rats.

RESULTS

The micturition interval (MI) in rats subjected to RF lesioning was significantly shorter than that in sham operated control rats. Diazepam (0.1 and 1 mg/kg intraperitoneally), baclofen (1 mg/kg intravenously) and MK-801 (0.1 and 1 mg/kg intravenously) did not change or shortened MI in control rats but it prolonged MI in lesioned rats. GYKI52466 (0.5 and 1 mg/kg intravenously) weakly prolonged MI in lesioned rats.

CONCLUSIONS

We consider that RF lesioning causes interruption of the inhibitory GABAergic neurons that lead from the forebrain to the PMC. This results in the activation of N-methyl-D-aspartate receptors in the PMC that are involved in the facilitation of voiding.

Universality in heavy fermion systems with general degeneracy

We discuss the relation between the T2 coefficient of electrical resistivity A and the T-linear specific-heat coefficient gamma for heavy-fermion systems with general N, where N is the degeneracy of quasiparticles. A set of experimental data reveals that the Kadowaki-Woods relation, A/gamma2=1 x 10(-5) muOmega cm(K mol/mJ)2, collapses remarkably for large-N systems, although this relation has been regarded to be commonly applicable to the Fermi liquids. Instead, based on the Fermi-liquid theory we propose a new relation, A /gamma2=1 x 10(-5) with A =A/1/2N(N-1) and gamma =gamma/1/2N(N-1). This new relation exhibits an excellent agreement with the data for the whole range of degenerate heavy fermions.

Anti-hyperglycemic effect of fangchinoline isolated from Stephania tetrandra Radix in streptozotocin-diabetic mice

Kampo medicine, Stephania tetrandra Radix (Stephania) in Boi-ogi-to increases the blood insulin level and falls the blood glucose level in streptozotocin (STZ)-diabetic ddY mice. These actions of Stephania are potentiated by Astragalus membranaceus Bunge Radix (Astragali) in Boi-ogi-to (Liu et al., J. Traditional Med., 17, 253-260, 2000). In the present study, actions of bis-benzylisoquinoline alkaloids isolated from Stephania were investigated in the hyperglycemia of STZ-diabetic mice. A main bis-benzylisoquinoline alkaloid, fangchinoline (0.3-3 mg/kg) significantly fell the blood glucose level of the diabetic mice in a dose-dependent manner. The effect of fangchinoline was 3.9-fold greater than that of water extract of Stephania. However, another main compound, tetrandrine (1-100 mg/kg) did not have any effect. The water extract of Astragali did not affect singly but potentiated the anti-hyperglycemic action of fangchinoline (0.3 mg/kg). Out of used compounds (1 mg/kg) isolated from Stephania, fangchinoline, fangchinoline 2'-N-alpha-oxide and 2'-N-norfangchinoline, which are substituted with 7-hydroxy side chain for 7-O-methyl side chain, decreased to near 50% of high blood glucose level. In addition, tetrandrine 2'-N-beta-oxide, tetrandrine 2'-N-alpha-oxide, tetrandrine 2-N-beta-oxide, fangchinoline 2'-N-alpha-oxide, which are added to 2- or 2'-N-oxide side chain, also decreased to near 50% of the high blood glucose level. In conclusion, fangchinoline but not tetrandrine from Stephania shows the anti-hyperglycemic action in the STZ-diabetic mice. The demethylation of 7-O-position and/or addition of 2- or 2'-N-oxide side chain in bis-benzylisoquinoline compounds in Stephania have a role for the induction of the anti-hyperglycemic actions.

Effects of adenosine triphosphate dependent potassium channel opener on bladder overactivity in rats with cerebral infarction

PURPOSE

We evaluated the effect of the adenosine triphosphate dependent K channel opener KRN2391 (N-cyano-N' -(2-nitroxyethyl)-3-pyridinecarboximidamide methanesulfonate) (Kirin Brewery Co., Gunma, Japan) on bladder overactivity induced by middle cerebral artery occlusion.

MATERIALS AND METHODS

At 7 days after implantation of a bladder catheter in male Sprague-Dawley rats a cannula for intracerebroventricular administration was implanted and the left middle cerebral artery was occluded with 4-zero monofilament nylon thread. At 22 hours after the induction of cerebral ischemia saline was infused into the bladder at a constant rate (200 microl. per minute) and a cystometrogram was obtained with the rat in the conscious state. KRN2391 (5 microl.) was administered in intracerebroventricular fashion at graded doses (0.15 to 15 microg.).

RESULTS

Bladder capacity in conscious rats was significantly reduced after left middle cerebral artery occlusion. Intracerebroventricular administration of KRN2391 significantly increased bladder capacity in cerebral infarcted but not in sham operated rats.

CONCLUSIONS

These results show that a adenosine triphosphate dependent K channel opener may be useful for neurogenic bladder overactivity after cerebral infarction via action on the central nervous system.

Method for simultaneous recording of the prostatic contractile and urethral pressure responses in anesthetized rats and the effects of tamsulosin

We simultaneously recorded the prostatic contractile and urethral pressure responses to electrical stimulation (ES) of the hypogastric nerves (HGNs) or phenylephrine in anesthetized rats and studied the effects of tamsulosin on these responses. At 0.01 and 0.1 mg/kg, i.v., tamsulosin inhibited the prostatic responses to ES of the HGNs in a dose-dependent manner, while at 1 microg/kg, i.v., it reduced the response to phenylephrine (0.01 mg/kg, i.v.) to about 26% of the nonantagonized level. These inhibitory effects on prostatic responses were maintained for 60 min. Tamsulosin exerted an inhibitory effect on the urethral response to ES of the HGNs at 0.01 mg/kg, i.v. but not at 0.1 mg/kg, i.v. At 1 microg/kg, i.v., tamsulosin also reduced the urethral response to phenylephrine to about 46% of the nonantagonized level; this effect was maintained for 60 min. Furthermore, tamsulosin was found to exert a stronger inhibitory effect on the prostatic response than on the urethral response induced by sympathetic nerve activation. Our findings suggest that rat urethral sympathetic nerve terminals may contain prejunctional alpha1 adrenoceptors that modulate the release of norepinephrine.

Sex difference in urethral response to electrical stimulation of efferent nerves in the pudendal sensory branch of rats

BACKGROUND

We reported sex difference in the urethral pressure (UP) response to electrical stimulation (ES) of the hypogastric nerve in rats. The purpose of the present study was to report on sex difference in the UP response to ES of the pudendal nerves (PN) in rats before and after injection of d-tubocurarine (d-tc).

METHODS

Wistar rats were anesthetized with urethane and alpha-chloralose. The L6-S1 trunk was exposed on the left side and resected. After resection of the motor branch of the PN the peripheral end of the L6-S1 trunk was stimulated. Fluid was infused into the urethra through a catheter inserted into the bladder neck at a constant rate (0.5 mL/10 min) and the infusion resistance was measured as the UP. When d-tc was injected, the rats were ventilated with an artificial respirator.

RESULTS

Though ES of the L6-S1 trunk caused fibrillation of the muscles near the tail and steep reduction of the UP, it caused elevation and reduction of UP in male and female rats, respectively, after intravenous injection of d-tc (0.3 mg/kg). ES of the sensory branch of the PN caused the elevation in male rats and reduction of the UP without injection of d-tc, and prazosin inhibited the UP elevation but the reduction was not inhibited by Nomega-nitro-L-arginine methyl ester.

CONCLUSION

In the sensory branch of the PN, the nerves innervating the smooth muscles in the urethral sphincter were contained. In male rats norepinephrine mediates the UP elevation, but the neurotransmitter that mediates the UP reduction in female rats is not known.

Effects of adrenergic alpha2-receptor agonists on urinary bladder contraction in conscious rats

We investigated the effects of the adrenergic alpha2-receptor agonists clonidine, oxymetazoline and tizanidine on bladder contractions induced by infusing fluid into the bladders of conscious male rats. I.v. clonidine and oxymetazoline (both 0.01 to 0.1 mg/kg) caused bladder hyperactivity, expressed by shortening of the intercontraction interval. Tizanidine (0.1 mg/kg, i.v.) caused slight shortening of the intercontraction interval. The rank order of potency was clonidine = oxymetazoline >> tizanidine. Intrathecal (i.t.) injection of 10 microg clonidine and oxymetazoline, and intracerebroventricular (i.c.v) injection at 15 microg, produced almost the same pattern of bladder hyperactivity as that observed after i.v. injection of these drugs (0.03 mg/kg, i.v.). For all three administration routes of clonidine and oxymetazoline, i.v. idazoxan (0.3 mg/kg) exerted an inhibitory effect on the bladder hyperactivity induced by these drugs, except i.c.v injection of oxymetazoline. I.t. phenylephrine (30 microg) did not change the intercontraction interval. Although i.c.v. phenylephrine (15 microg) shortened the intercontraction interval, the potency was weaker than those of i.c.v. clonidine and oxymetazoline (15 microg). These results suggest that clonidine and oxymetazoline cause bladder hyperactivity by acting at adrenergic alpha2 receptors in the micturition centers of the lumbosacral and supraspinal regions.

Sex differences in urethral pressure response to electrical stimulation of the hypogastric nerves in rats

PURPOSE

This experiment was performed to study the pharmacology of transmitters mediating the response, and the characteristics of the hypogastric nerve (HGN) of female rats, because electrical stimulation of the HGN was found to unexpectedly reduce urethral pressure in female rats.

MATERIALS AND METHODS

Male and female Wistar rats (weighing about 250 gm.), 10 weeks and 6 months old, respectively, were used under anesthesia. Fluid was infused from the bladder neck into the urethral lumen at a constant rate (0.5 ml./10 minutes), and infusion pressure signals were measured. Bilateral HGNs were electrically stimulated at 5 and 10 Hz for 30 s.

RESULTS

Electrical stimulation of the HGN reduced urethral infusion pressure in about 80% of the female rats, and the introduction of N(omega)-nitro-L-arginine methylester (L-NAME, 30 mg./rat, i.v.) elevated the urethral pressure response from a reduced state. Prazosin (0.1 mg./kg., i.v.) and hexamethonium (10 mg./kg., i.v.), which inhibited elevation of urethral pressure in male rats, also reversed and inhibited the elevation of urethral pressure in the female rats treated with L-NAME.

CONCLUSION

The HGN in female rats contained nerve endings that released nitric oxide (NO) and norepinephrine (NE). NO released during HGN stimulation inhibited the release of (NE) and reduced urethral infusion pressure in female rats. Nerves with synapses in the pelvic ganglia released NE in both male and female rats, but nerves that released NO did not have synapses in the ganglia. Only NE was released from the HGN nerve endings in male rats.

Effects of nifedipine on bladder overactivity in rats with cerebral infarction

PURPOSE

Our objective was to evaluate the effect of the calcium (Ca2+) channel blocking agent nifedipine on bladder overactivity induced by middle cerebral artery (MCA) occlusion and determine its site of action.

MATERIALS AND METHODS

Seven days after implantation of a bladder catheter, a cannula for intracerebroventricular and intrathecal administration was implanted and the left MCA was occluded with 4-0 monofilament nylon thread in male SD rats. Twenty-four hours after the induction of cerebral ischemia, saline was infused into the bladder at a constant rate (200 microL/min.) and cystometrogram was measured in conscious state. Nifedipine was administered intracerebroventricularly (5 microL) or intrathecally (20 microL) at graded doses (0.15 ng.-0.15 microg., 0.15 microg. -1.5 microg., respectively).

RESULTS

Bladder capacity in conscious rats was significantly reduced after the left MCA occlusion. Intracerebroventricular administration of nifedipine significantly increased bladder capacity in cerebral infarcted rats but not in sham operated rats. Furthermore there was no significant difference in bladder capacity between before and after intrathecal administration of nifedipine in cerebral infarcted rats.

CONCLUSION

These results show that Ca2+ channel blocking agents can operate especially on the supraspinal central nervous system rather than on the spinal system in rats with neurogenic bladder overactivity following cerebral infarction.

Effect of K+ channel openers, KRN2391 and Ki1769, and nitroglycerin on the urinary tract of rats in vivo

The effects of KRN2391 (N-cyano-N'-(nitroxyethyl)-3-pyridine carboximidamide methane-sulfonate), which possesses ATP-sensitive potassium (K+) channel opening (KCO) activity and nitrate activity; Ki1769 (N-cyano-N'-(phenylethyl)-3-pyridinecarboximidamide methanesulfonate), which possesses only KCO activity; and nitroglycerin (NG) were determined on the motility of the ureter, urinary bladder and urethra of rats. Bladder contraction was induced by infusion of fluid into the bladder of conscious rats and recorded on a cystometrogram. KRN2391 and Ki1769 (both 0.3 mg/kg, i.v.) prolonged the micturition interval immediately after the injection, but NG (5 mg/kg, i.v.) did not. Peristaltic movement of the ureter, recorded in anesthetized rats, was inhibited by i.v. injection of KRN2391 and Ki1769 (both 0.03 mg/kg). However, when NG, NaNO2, N-nitro L-arginine methylester and methylene blue were applied directly to the ureter, no change in movement of the ureter was detected. KRN2391 (0.03 mg/kg, i.v.) and Ki1769 (0.3 mg/kg, i.v.) reduced the resistance to fluid infusion through the urethral lumen in anesthetized rats, whereas NG (0.5 mg/kg, i.v.) only reduced this resistance transiently. These results indicate that KCO activity had an inhibitory effect on the motility of the ureter, bladder and urethra. On the other hand, nitrate activity had an inhibitory effect on urethral tonus, corresponding to that induced by KCO activity.

Inhibitory effects of tetrandrine and related synthetic compounds on angiogenesis in streptozotocin-diabetic rodents

Structure-activity relationships of tetrandrine, isolated from a Kampo medicine, Stephania tetrandrae S. MOORE (root), and related synthetic compounds, were investigated in in vitro fetal bovine serum (FBS)-stimulated angiogenesis of cultured choroids in streptozotocin-diabetic Wistar rats, and air-pouch granuloma angiogenesis in vivo in diabetic mice. Tetrandrine, KS-1-1 (6,7-dimethoxy-1-[[4-[5-(6,7-dimethoxy-2-methyl-1,2,3,4-tetrahydroiso quinolinyl)methyl-2-methoxy]phenoxy]benzyl]-2-methyl-1,2,3,4-tetrahyd roisoquinoline), and KS-1-4 (6,7-dimethoxy-1-[[4-[4-(6,7-dimethoxy-2-methyl-1,2,3,4-tetrahydroiso quinolinyl)methyl]phenoxy]benzyl]-2-methyl-1,2,3,4-tetrahydroisoquino line), potently inhibited choroidal angiogenesis and air-pouch granuloma angiogenesis in the diabetic state. Their inhibitory effects on diabetic choroids were greater than those on normal choroids. Among these compounds, KS-1-4 inhibited only diabetic angiogenesis. These compounds significantly inhibited FBS-stimulated tube formation in vascular endothelial cells from normal rats. Tetrandrine and KS-1-4, but not KS-1-1, inhibited vascular endothelial growth factor- and platelet-derived growth factor-BB-stimulated angiogenesis in normal choroids. The bis[tetrahydroisoquinoline] moiety, connected by oxy-bis[phenylenemethylene] and 2,2'-dimethyl groups in tetrandrine, contributes to the inhibition of diabetic choroidal angiogenesis. KS-1-4 may be a candidate for anti-choroidopathy and retinopathy drugs in the diabetic state.

A quantitative assay for angiogenesis of cultured choroidal tissues in streptozotocin-diabetic Wistar and spontaneously diabetic GK rats

Angiogenesis of cultured choroids was quantitatively assayed in spontaneously diabetic GK and a bolus-treated streptozotocin (STZ)-diabetic Wistar rats. The number and total length of microvessels budded from cultured choroidal explants were measured to use as angiogenic indices. Both indices in 10-week-old Wistar rats were increased in parallel by 5% fetal bovine serum (FBS) from days 2 to 7 in culture. These indices in STZ-rats (10 weeks of age) were increased by 5% FBS to a greater extent than those in age-matched normal rats. These enhanced actions of FBS were concentration-dependent. The explants of 16-week-old GK rats also increased these indices to a greater extent than those of age-matched Wistar rats. Aging to 18 weeks of age also increased choroidal angiogenesis in the normal rats. In conclusion, the assay model of choroidal angiogenesis was established by determining the number and length of microvessels in cultured choroidal explants. The diabetic states of STZ-Wistar and GK rats enhanced FBS-induced choroidal angiogenesis. This assay model is useful for determining angiogenic activity of growth factors and effective drugs in diabetic choroidopathy and retinopathy.

Urinary bladder response to hypogastric nerve stimulation after bilateral resection of the pelvic nerve or spinal cord injury in rats

BACKGROUND

We examined the mechanism of urinary bladder motility return after bladder areflexia induced by interruption of the sacral parasympathetic outflow to the urinary bladder following damage to the sacral cord or pelvic nerves in the rat.

METHODS

The L6 and S1 nerve bundles were resected near the vertebrae, and bilateral pelvic nerve resections (PNR) performed. Spinal cord injury (SCI) was performed by means of a legion generator at the T12 vertebra. Thirty days after PNR and SCI, cystometrograms were recorded under anesthesia.

RESULTS

In all rats subjected to PNR or SCI, overflow incontinence continued, yet some rats subjected to SCI recovered within 2 weeks after the operation. Cystometrograms showed that repetitive bladder contractions appeared in rats subjected to SCI irrespective of hypogastric nerve (HGN) innervation, while bladder contractions did not appear in rats subjected to PNR. Electrical stimulation of the HGN induced higher bladder pressure elevation in rats who underwent PNR than in rats subjected to SCI.

CONCLUSIONS

These results suggest that the generation of repetitive bladder contractions induced by bladder distention after bladder areflexia requires the presence of intact pelvic nerves that transmit sacral cord-originating excitatory information to the bladder. However, the HGN system and functioning pelvic nerve ganglia are not involved in this process. Also, the connection from the preganglionic HGN to the postganglionic parasympathetic nerves in the pelvic plexus did not form after PNR.

Effects of levcromakalim on ureteral peristaltic function and cystometrogram in rats

We studied the effect of levcromakalim on the function of the urinary tract in rats. Using anesthetized rats, ureteral peristaltic movement of only the ureter region or the ureter with the kidney was induced by fluid infusion into the ureter lumen. Levcromakalim (0.03 and 0.3 mg/kg, i.v.) exerted a stronger inhibitory effect on the peristaltic movement of the ureter region distant from the pelvis than on that near the pelvis, and the inhibitory effect of levcromakalim (0.03 mg/kg, i.v.) was not antagonized by glibenclamide (0.1 mg/kg, i.v. or 10 mg/kg, i.p.). Topical application of levcromakalim (injection volume, 0.1 ml; 10(-4) or 10(-3) M), which was injected via a vessel near the ureter inhibited ureteral peristaltic movement and the inhibitory effect levcromakalim (10(-4) M), was not antagonized by glibenclamide (10(-3) M) injected via the same route. Levcromakalim (0.3 mg/kg, i.v.) did not interrupt micturition in anesthetized and conscious rats. In conscious rats, the micturition interval was prolonged; and in anesthetized rats, the peak pressure during micturition was reduced. After injection of levcromakalim (0.3 mg/kg, i.v.), vesicoureteral reflux did not occur. In the movements of the ureter, urinary bladder and urethra, levcromakalim exerted the strongest inhibitory effect on the ureteral peristalsis.

A simple method for measurement of ureteric peristaltic function in vivo and the effects of drugs acting on ion channels applied from the ureter lumen in anesthetized rats

In supine anesthetized rats, two cannulae were inserted into a unilateral ureter near the kidney and urinary bladder, respectively. Fluid from a reservoir placed approximately 27 cm above the rat was infused into the ureter lumen through the cannula near the kidney, and the resulting peristaltic pressure signals were measured from the cannula near the bladder. When drugs acting on ion channels were applied from the ureter lumen and their effects on the peristaltic pressure signals were studied, the K+ channel opener BRL 38227 (1 x 10(-4) M and 1 x 10(-3) M) was found to decrease the frequency dose-dependently. However, the K+ channel blockers glibenclamide and 4-aminopyridine at 1 x 10(-3) M did not affect peristaltic movement. Nifedipine (1 x 10(-5) M and 1 x 10(-4) M) decreased the frequency of peristalsis, but the effect was weaker than that of BRL 38227. Lidocaine at very high concentration (1.5 x 10(-2) and 1.5 x 10(-1) M) decreased the amplitude and increased the frequency of the peristaltic signals. These results indicate that the K+ channel opener has the most inhibitory effect on ureteral peristaltic function.

Involvement of alpha 2-adrenoceptors in the sacral micturition reflex in rats

We have studied the effects of intrathecally-injected drugs that act on alpha-adrenoceptors in the urinary bladder reflex contractile activity evoked by continuous infusion of fluid into the bladder of anesthetized rats. Clonidine (10 and 30 micrograms) facilitated and yohimbine (100 micrograms) abolished the bladder contractile activity, and pretreatment with yohimbine (30 micrograms) inhibited the effect of clonidine (10 micrograms). Phenylephrine (60 micrograms) abolished the bladder contractile activity, but prazosin (40 micrograms) had no significant effect on it. The bladder contractions induced by electrical stimulation of the pontine micturition center were inhibited by yohimbine in a dose-dependent manner. These results suggest that transmission in the descending neurons from the pontine micturition center to the sacral parasympathetic neurons that control bladder motility is mediated by alpha 2-adrenoceptors in rats.

Effects of adrenergic agonists on an experimental urinary incontinence model in anesthetized rabbits

We have developed an experimental urinary incontinence model in anesthetized female rabbits, in order to study the effects of alpha-adrenergic receptor agonists on it in vivo. Micturition was induced artificially by electrical stimulation of the abdomen of rabbits receiving a continuous infusion of glucose-free. Tyrode's solution into the urinary bladder. Alpha-1 adrenergic agonists, phenylephrine (1 mg/kg, i.v.) and the newly synthesized agent ST-1059 (1 mg/kg, i.v.) and its prodrug midodrine (10 mg/kg), which was intraduodenally administered, elevated the bladder pressure and arrested micturition induced by electrical stimulation. Prazosin (0.1 mg/kg, i.v.) inhibited these effects of phenylephrine. The effect of an alpha-2 agonist, clonidine (1 mg/kg, i.v.), on micturition induced by electrical stimulation was not clearly defined. This study demonstrates that alpha-1 adrenergic agonists can arrest artificially-induced micturition via urethral contraction. This method may be useful for evaluating the effect of a drug on urethral leakage in vivo.

Dopamine receptor subtypes that induce hyperactive urinary bladder response in anesthetized rats

In anesthetized rats, SKF 38393 (10 mg/kg, i.v.) did not facilitate urinary bladder motility, but bromocriptine (BR, 5 mg/kg, i.v.) alone and the combination of BR (1 mg/kg, i.v.) and SKF 38393 (1 mg/kg, i.v.) induced a hyperactive bladder response (HBR). Both HBR induced by BR alone or BR and SKF 38393 combined was suppressed by SCH 23390, sulpiride or haloperidol. These results indicate that HBR is mediated by the activation of D-2 receptors, and the effects of D-2 agonists on bladder motility are potentiated by the simultaneous stimulation of D-1 receptors.

Evaluation of drugs for treatment of urinary bladder dysfunction in conscious rats with intact pelvic nerve and after resection of the left pelvic nerve

We studied the effects of drugs used for treatment of bladder dysfunction in conscious rats with intact pelvic nerves and also in rats at one or two weeks after nerve decentralization on the left side. Bladder contraction accompanying micturition was continuously induced by infusion of solution at a constant rate. When the effects of oxybutynin (3 mg/kg, i.p.) and terodiline (3 and 10 mg/kg, i.p.) on the cystometrogram were studied for about 2 hr, these drugs shortened and then prolonged the micturition interval (MI), but atropine (1 and 5 mg/kg, i.p.), butylscopolamine (20 mg/kg, i.p.) and nifedipine (3 mg/kg, i.p.) exhibited only a shortening effect on the MI. After injection of oxybutynin (10 mg/kg, i.p.), solution dribbled from the urethra for about 30 min. Terodiline (3 mg/kg) caused ischuria in the rats one week after resection of the left pelvic nerve, but not in the rats two weeks after surgery. Physostigmine (0.3 mg/kg, i.p.) improved micturition in the rats one week after surgery, but the effect was not evident in the rats with intact pelvic nerves. It was found that the drugs used for treating failure to store or expel urine exhibited a beneficial effect on micturition in rats with intact pelvic nerves and also in rats one week after nerve decentralization, respectively.

Effects of apomorphine on urinary bladder motility in anesthetized rats

We studied the effects of apomorphine (AM) on bladder motility in anesthetized rats in which Tyrode's solution was continuously infused into the bladder at a constant rate, including an almost constant rate of bladder contraction accompanying micturition. AM at a dose of 1 mg/kg, i.v., caused a hyperactive bladder response, during which micturition disappeared. AM (12.5 micrograms for intracerebroventricular (i.c.v.) injection or 50 micrograms for intrathecal (i.t.) injection also caused a hyperactive response in about half of the rats. Supersensitization to AM appeared in reserpine-treated rats (2.5 mg/kg, i.p., 48 and 24 hr before the experiment). Haloperidol (1 mg/kg, i.v.) or SCH 23390 (5 mg/kg, i.v.) completely suppressed the hyperactive bladder response induced by AM (5 mg/kg, i.v.), and then the bladder contraction accompanying micturition reappeared after administration of these drugs. Pretreatment with sulpiride (100 mg/kg, i.p.) for 60 min, which hardly affected the bladder contraction induced by infusion of Tyrode's solution, suppressed the hyperactive bladder response induced by AM. These results suggest that the hyperactive bladder response induced by i.v.-injected AM results from synchronous stimulation of the micturition reflex centers in the brain stem and sacral cord and that the hyperactive bladder response is elicited via both D1 and D2 receptors.

Effects of central nervous system-acting drugs on urinary bladder contraction in unanesthetized rats

We studied the effects of drugs on urinary bladder contraction in unanesthetized (UA) rats using the same method as that previously employed to investigate similar effects in urethane and alpha-chloralose-anesthetized (A) rats. The surgical procedure was performed under halothane anesthesia, and after the recovery, the rats were restricted in a Ballman cage during the experiment. The pattern of the cystometrogram obtained in UA rats was very similar to that in A rats, and almost the same pattern was maintained for at least three hours. Baclofen (10 mg/kg, i.p.), morphine (10 mg/kg, i.p.) and pentobarbital (20 mg/kg, i.p.) completely inhibited the bladder contraction at doses only double those at which the same drugs inhibited the bladder contraction in A rats when i.v. injected. When the bladder pressure rose almost to the level of the peak pressure existing before injection of these drugs, the instilled solution leaked from the penis. On the other hand, even after injection of diazepam (5 mg/kg, i.p.) at a dose five times greater than the minimum amount necessary for complete inhibition of bladder contraction in A rats, the bladder contraction accompanying micturition continued in UA rats. It appears that the inhibitory effect of diazepam on bladder contraction in rats is potentiated by anesthesia.

A study of morphine-induced urinary retention in anesthetized rats capable of micturition

The nature of morphine-induced urinary retention was studied in anesthetized rats in which the bladder contraction accompanying micturition could be observed. Morphine (0.1 mg/kg, i.v.) prolonged the micturition interval and increased the level of micturition threshold. Morphine (1 mg/kg, i.v.) completely inhibited bladder contraction and bladder pressure was elevated until solution leaked from the penis, but the bladder pressure after inhibition by morphine (1 and 5 mg/kg, i.v.) did not significantly rise over the peak pressure level during micturition before injection of morphine. The inhibitory effect of morphine (1 and 5 mg/kg, i.v.) was reversed by naloxone (0.1 mg/kg, i.v.). Morphine (5 mg/kg, i.v.) did not increase the pressure induced by infusion of solution from near the bladder neck to the urethra. After intracerebroventricular (i.c.v.) and intrathecal (i.t.) administration of morphine (1 microgram), the micturition interval was prolonged and the level of micturition threshold was increased. Morphine (5 micrograms, i.c.v. and i.t.) inhibited bladder contraction and naloxone (5 micrograms, i.c.v. and i.t.) reversed the inhibitory effect of morphine injected by the same administration route. From these results, urinary retention induced by systematically injected morphine was considered to result from inhibition of bladder function mediated via opioid receptors of the micturition centers in the supraspinal and spinal regions.

In vivo inhibitory effects of stimulation at the central end of the pelvic nerve severed from urinary bladder on urinary bladder contraction in rats

Two- or five-Hz electrical stimulation of the central end of the left pelvic nerve severed from the urinary bladder in rats inhibited bladder contraction induced by intravesical infusion of Tyrode's solution. Inhibition of bladder motility by 2-Hz nerve stimulation appeared after pretreatment with strychnine (0.3 mg/kg, i.v.), naloxone (1 mg/kg, i.v.) and picrotoxin (1 mg/kg, i.v.). Hypogastric nerve stimulation, however, did not affect bladder contraction. These results suggest the presence of an inhibitory mechanism on the pelvic motoneuron activated by contralateral pelvic nerve stimulation in rats.

The effect of baclofen on the urinary bladder contraction accompanying micturition in anesthetized rats

We studied the effects of baclofen on the bladder contraction induced by infusion of Tyrode's solution into the urinary bladder in anesthetized rats. Baclofen (5 mg/kg, i.v.) completely inhibited bladder contraction and abolished the efferent discharges recorded from the left pelvic nerve, causing the bladder pressure to rise until solution leaked from the penis. The inhibitory effect of baclofen (5 mg/kg, i.v.) could not be reversed by picrotoxin (1 mg/kg, i.v., twice with an interval of 10 min) or naloxone (1 mg/kg, i.v.). In parallel with convulsion, strychnine (1 mg/kg, i.v.) contracted the bladder which had been inhibited by baclofen and generated electrical activities consisting of efferent discharges and electromyograms. The dose of intracerebroventricularly or intrathecally injected baclofen which completely inhibited the bladder contraction was 0.1 or 10 micrograms, respectively. After the inhibition of bladder contraction by i.v. injection of baclofen, electrical stimulation of the sacral cord could contract the bladder and cause a fall in bladder pressure to around the level existing after micturition. From these results, the active site of baclofen which is related to the inhibition of bladder contraction is thought to be the micturition center in the brain stem.

Pharmacological studies of the new centrally acting muscle relaxant 4'-ethyl-2-methyl-3-pyrrolidinopropiophenone hydrochloride

The pharmacological properties of 4'-ethyl-2-methyl-3-pyrrolidinopropiophenone hydrochloride (HSR-770), a new centrally acting muscle relaxant, were investigated in experimental animals. HSR-770, within a dose range of 1-10 mg/kg i.v., relaxed alpha- and gamma-rigidities in rats, the dose required to relax gamma-rigidity being lower than the dose required to relax alpha-rigidity. When HSR-770 was intraduodenally (i.d.) administered within a dose range of 25-50 mg/kg, the relaxant activity on alpha-rigidity was potent and long-lasting in comparison with eperisone or tolperisone. HSR-770 inhibited flexor reflex more strongly than patellar reflex in a dose-dependent manner within a dose range of 2.5-10 mg/kg i.v. or 25 and 50 mg/kg i.d. in anesthetized cats. In spinal cts, HSR-770 (5 and 10 mg/kg i.v.) inhibited flexor reflex but this potency was weaker than that in anesthetized cats. HSR-770 (12.5-50 mg/kg i.d.) inhibited he crossed extensor reflex in anesthetized rats. In spinal cats, HSR-770 inhibited mono- and polysynaptic reflex potentials to the same extent and also depressed dorsal root reflex potential at 5 and 10 mg/kg i.v. HSR-770 at a dose (50 mg/kg p.o.) which exerted muscle relaxant activity on both rigidity and flexor reflex, had little effect on spontaneous motor activity (mice), hexobarbital-induced sleeping time (mice) and conditioned avoidance response (rats). These results indicate that HSR-770 is a potent centrally acting muscle relaxant and that its central nervous system depressant activity is relatively weak.

[Central muscle relaxant activities of 2-methyl-3-aminopropiophenone derivatives]

In this experiment, we synthetized new 2-methyl-3-aminopropiophenone (MP) derivatives, whose structure is known to have central muscle relaxant activities, and quinolizidine and indan . tetralin derivatives derived from MP by cyclization, and we investigated the central muscle relaxant activity. Among the quinolizidine derivatives, there was a very strong central depressant agent, trans (3H, 9aH)-3-(p-chloro) benzoyl-quinolizidine (HSR-740), and among the indan . tetralin derivatives, there was an excitant agents, trans (1H, 2H)-5-methoxy-3, 3-dimethyl-2-piperidinomethyl indan-1-ol (HSR-719). From the results, these derivatives were not considered to be adequate for central muscle relaxant. Among the MP derivatives, (4'-chloro-2'-methoxy-3-piperidino) propiophenone HCl (HSR-733) and (4'-ethyl-2-methyl-3-pyrrolidino) propiophenone HCl (HSR-770) strongly inhibited the cooperative movement in the rotating rod method using mice, and it exerted almost the same depressant activity on the cross extensor reflex using alpha-chloralose anesthetized rats. However, the inhibitory effects of HSR-733 on the anemic decerebrate rigidity and the rigidity induced by intracollicular decerebration in rats were weaker than those of HSR-770 and eperisone. In spinal cats, at a low dose (5 mg/kg, i.v.), HSR-733 depressed monosynaptic and dorsal root reflex potentials as compared with polysynaptic reflex potentials, and inhibitory effects of HSR-733 on these three reflex potentials were more potent than those of eperisone and HSR-770. Although HSR-770 acts on the spinal cord and supraspinal level on which eperisone has been reported to act, HSR-733 may mainly act on the spinal cord. These results indicate that the MP derivative with a 2-methyl group may be suitable as a central muscle relaxant. HSR-770, which has equipotent muscle relaxant activity to eperisone, exerted strong inhibitory effects on oxotremorine-induced tremor and weak inhibitory effects on spontaneous motor activity in the Animex method using mice, as compared with eperisone.

In vivo effects of drugs that act on the autonomic nervous system on the rat urinary bladder contraction accompanying micturition

We prepared an experimental system to study the effects of drugs on urinary bladder contraction and micturition simultaneously in rats anesthetized with urethane (1 g/kg, s.c.) and alpha-chloralose (25 mg/kg, s.c.). When Tyrode's solution was infused at a constant rate (0.8-1 ml/10 min) through a needle inserted into the bladder from the left ureter, the bladder pressure gradually and then steeply rose, and micturition took place. These changes in bladder pressure and micturition were constantly repeated. In this model, drugs which partially inhibited the bladder contractile force, e.g., atropine (0.01-1 mg/kg, i.v.) and hexamethonium (C6, 5 mg/kg, i.v.) increased the frequency of bladder contraction instead of decreasing the amount of solution excreted from the penis by bladder contraction. The rate of afferent discharges during bladder filling was increased after injection of atropine or C6, and this increase was considered to be responsible for the induction of the increase in the frequency of bladder contraction. Drugs which inhibited the bladder contraction and interrupted micturition, e.g., C6 (20 mg/kg, i.v.) raised the bladder pressure until the solution leaked from the penis. As phentolamine (5 mg/kg, i.v.) or propranolol (1 mg/kg, i.v.) did not facilitate bladder motility but rather inhibited it, the inhibitory action of sympathetic nerves on bladder motility was considered to be weak in rats. This model was useful for studying the effect of drugs on bladder motility and micturition reflex.