Effects of TAK-802, a novel acetylcholinesterase inhibitor, on distension-induced rhythmic bladder contractions in rats and guinea pigs

The effects of the concentration-dependent erythrocyte distribution of TAK-802, a potent acetylcholinesterase inhibitor, on rat pharmacokinetics

The purpose of this study was to investigate the effect of the concentration-dependent erythrocyte distribution of TAK-802, a potent acetylcholinesterase inhibitor, on rat pharmacokinetics. In an ascending oral dose study, the maximum plasma concentration (C_max ) of TAK-802 increased in a dose-dependent manner. The time to reach C_max decreased as the dose increased, whereas the total clearance was independent of the tested dose range. In this intravenous (i.v.) ascending dose study in rats, the apparent distribution volumes at steady state decreased, and the apparent terminal elimination rate constants increased with TAK-802 dose escalation. A marked concentration dependency was observed in an associated in vitro erythrocyte distribution study. The in vitro erythrocyte distribution study results and a relationship analysis between the plasma and blood concentrations of TAK-802 after i.v. dosing revealed that the characteristics of the erythrocyte distribution could be expressed by Langmuir's adsorption formula. The concentration-time profiles of TAK-802 in plasma and whole blood calculated using a nonlinear pharmacokinetic model incorporating the concentration-dependent erythrocyte distribution with optimized parameters fit well to the observed plasma and blood concentration profiles obtained from the i.v. ascending dose study. These results indicate that the concentration-dependent erythrocyte distribution plays a major role in the nonlinear pharmacokinetics of TAK-802 in rats. Copyright © 2016 John Wiley & Sons, Ltd.

Netupitant, a Potent and Highly Selective NK1 Receptor Antagonist, Alleviates Acetic Acid-Induced Bladder Overactivity in Anesthetized Guinea-Pigs

Introduction. Tachykinins potently contract the isolated urinary bladder from a number of animal species and play an important role in the regulation of the micturition reflex. On the guinea-pig isolated urinary bladder we examined the effects of a new potent and selective NK1 receptor antagonist (netupitant) on the contractions induced by a selective NK1 receptor agonist, SP-methylester (SP-OMe). Moreover, the effects of netupitant and another selective NK1 antagonist (L-733,060) were studied in anesthetized guinea-pigs using two experimental models, the isovolumetric bladder contractions and a model of bladder overactivity induced by intravesical administration of acetic acid (AA). Methods and Results. Detrusor muscle strips were mounted in 5 mL organ baths and isometric contractions to cumulative concentrations of SP-OME were recorded before and after incubation with increasing concentrations of netupitant. In anesthetized female guinea-pigs, reflex bladder activity was examined under isovolumetric conditions with the bladder distended with saline or during cystometry using intravesical infusion of AA. After a 30 min stabilization period, netupitant (0.1-3 mg/kg, i.v.) or L-733,060 (3-10 mg/kg, i.v.) were administered. In the detrusor muscle, netupitant produced a concentration-dependent inhibition (mean pKB = 9.24) of the responses to SP-OMe. Under isovolumetric conditions, netupitant or L-733,060 reduced bladder contraction frequency in a dose-dependent manner, but neither drug changed bladder contraction amplitude. In the AA model, netupitant dose-dependently increased intercontraction interval (ICI) but had no effect on the amplitude of micturition (AM). L-733,060 dose-dependently increased ICI also but this effect was paralleled by a significant reduction of AM. Conclusion. Netupitant decreases the frequency of reflex bladder contractions without altering their amplitude, suggesting that this drug targets the afferent limb of the micturition reflex circuit and therefore may be useful clinically in treating bladder overactivity symptoms.

Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart

The physically adsorbed acetylcholinesterase on mesoporous silicon surface is presented. The catalytic behavior of immobilized enzyme was assessed by spectrophotometric bioassay. The immobilization enhanced the reusability, shelf life and thermal as well as pH stability

A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4–9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness.

Effects of Silodosin, an α1A-Adrenoceptor Antagonist, and Distigmine, an Acetylcholinesterase Inhibitor, and Their Combined Effects on Impaired Voiding Function in Zucker Diabetic Fatty Rats

BACKGROUND/AIMS

To evaluate the effects of silodosin (α1A-adrenoceptor antagonist) and distigmine (acetylcholinesterase inhibitor), alone or in combination, on voiding dysfunction in Zucker diabetic fatty (ZDF) rats, a type 2 diabetes model, by pressure flow study.

METHODS

Male ZDF rats were anesthetized with urethane and a catheter was implanted into the bladder through the dome. Saline was continuously infused into the bladder at 6 ml/h to induce the micturition reflex. Intravesical pressure and micturition volume were recorded continuously and various urodynamic parameters were calculated using a waveform analysis system.

RESULTS

Increased bladder capacity, residual volume, and urethral resistance and decreased maximum detrusor contraction velocity and urine flow rate, considered to be detrusor underactivity-like symptoms, were observed in ZDF rats. Although both silodosin and distigmine improved impaired voiding function, administration of both drugs in combination was more effective than either drug alone.

CONCLUSIONS

ZDF rats showed symptoms suggestive of detrusor underactivity, and silodosin tended to ameliorate these symptoms in ZDF rats. These results suggested that an α1A-adrenoceptor antagonists may be effective against the voiding disorder accompanying not only bladder outlet obstruction but also deficiency of bladder function. Moreover, combined administration of an α1A-adrenoceptor antagonist with an acetylcholinesterase inhibitor may have additive efficacy in clinical use.

Differential effects of TAK-802, a selective acetylcholinesterase inhibitor, and carbamate acetylcholinesterase inhibitors on contraction of the detrusor smooth muscle of the guinea pig

The aim of this study was to compare the effects of TAK-802, a novel acetylcholinesterase (AChE) inhibitor, and carbamate AChE inhibitors on the detrusor smooth muscle contractility in vitro using isometric tension measurements. The effects of drugs on the nicotine-induced contractions and basal tone of the isolated detrusor muscle of the guinea pig were examined. All of the drugs, namely, TAK-802, distigmine, neostigmine and pyridostigmine, enhanced the nicotine-induced contractions of the muscle strips in a concentration-dependent manner. On the other hand, while neostigmine and pyridostigmine markedly increased the basal tone, and distigmine slightly but significantly increased the basal tone, TAK-802 had no influence on the basal tone of the muscle strips at all. However, following co-treatment with tetraisopropyl pyrophosphoramide, a selective butyrylcholinesterase (BuChE) inhibitor, TAK-802 also did increase the basal tone. The increase of the basal tone by all of the above treatments was completely abolished by atropine. These results reveal that while all the four AChE inhibitors enhanced endogenous acetylcholine-induced contractions, their effects on the basal tone were clearly different. The effect of carbamate AChE inhibitors of increasing the basal tone could be partly attributed to their dual inhibition of both AChE and BuChE, because both cholinesterases may play a critical role in maintaining the resting tension of the urinary bladder. TAK-802, however, did not increase the basal tone of the detrusor muscle strips, probably because of its selective inhibitory effect against AChE. The effect of carbamate AChE inhibitors on the basal tone of the detrusor muscle may explain the decrease of bladder compliance observed in our previous study on guinea pigs as well as the deterioration of the bladder-storage function reported with their clinical use.

Effects of TAK-802, a novel acetylcholinesterase inhibitor, and tamsulosin, an alpha1-adrenoceptor antagonist, and their synergistic effects on the urodynamic characteristics in a guinea-pig model of functional bladder outlet obstruction

OBJECTIVE

To investigate the effects of TAK-802, a potent acetylcholinesterase inhibitor, and tamsulosin, an alpha1-adrenoceptor antagonist, and their concomitant administration on the urodynamic characteristics in a guinea-pig model of functional bladder outlet obstruction.

MATERIALS AND METHODS

Cystometry was performed in urethane-anaesthetized guinea pigs, and various urodynamic variables, including the maximum flow rate (Qmax), voiding efficiency, maximum intravesical pressure (Pvesmax) and intravesical pressure at Qmax (PvesQmax), were measured before and after administration of the drugs in combination and alone.

RESULTS

Continuous intravenous infusion of phenylephrine, an alpha1-adrenoceptor agonist (1-6 microg/animal/min), dose-dependently decreased the Qmax and voiding efficiency, and increased the Pvesmax and PvesQmax, possibly by constricting urethral smooth muscle. In this functional urethral constriction model, both TAK-802 at 1 and 10 microg/kg and tamsulosin at 3 and 10 microg/kg (intravenously) caused increasing effects on the Qmax and voiding efficiency. The effects were more apparent with combined exposure. Although the Pvesmax was dose-dependently increased by TAK-802 alone, the effects were completely abolished by concomitant treatment with tamsulosin.

CONCLUSION

These results suggest that TAK-802 and tamsulosin have synergistic effects in increasing the Qmax and voiding efficiency, and TAK-802 does not inhibit the decreasing effect of tamsulosin on urethral resistance. That TAK-802 increased Pves when administered alone implies that monotherapy using an acetylcholinesterase inhibitor should be withheld in patients with voiding dysfunction caused by obvious bladder outlet obstruction with benign prostatic hyperplasia, to avoid disorders of the upper urinary tracts, and it should be used with an alpha1-adrenoceptor antagonist. Whether TAK-802 combined with an alpha1-adrenoceptor antagonist confers additional clinical benefit is not yet known.

Novel acetylcholinesterase inhibitor as increasing agent on rhythmic bladder contractions: SAR of 8-{3-[1-(3-fluorobenzyl)piperidin-4-yl]propanoyl}-1,2,5,6-tetrahydro-4H-pyrrolo[3,2,1-ij]quinolin-4-one (TAK-802) and related compounds

As part of an on-going investigation to develop an increasing agent on rhythmic bladder contractions, 1-aryl-3-(1-benzylpiperidin-4-yl)propanones were synthesized and examined as noncarbamate acetylcholinesterase (AChE) inhibitors. Among compounds with various aryl groups, 1,2,5,6-tetrahydro-4H-pyrrolo[3,2,1-ij]quinolin-4-one derivative 9c was found to possess a potent AChE inhibition activity with an IC(50) value of 1.3nM. The compound 9c increased rhythmic bladder contractions in Guinea pigs and rats without affecting the basal intravesical pressure, which suggests that 9c may be useful for the treatment of voiding dysfunction caused by detrusor underactivity.

Effects of TAK-802, a novel acetylcholinesterase inhibitor, and various cholinomimetics on the urodynamic characteristics in anesthetized guinea pigs

In the present study, we investigated the effects of cholinomimetic drugs on the urodynamic characteristics in anesthetized guinea pigs. 8-[3-[1-[(3-fluorophenyl)methyl]-4-piperidinyl]-1-oxopropyl]-1,2,5,6-tetrahydro-4H-pyrrolo[3,2,1-ij]quinolin-4-one (TAK-802), a novel acetylcholinesterase inhibitor, (0.003-0.03 mg/kg, i.v.) increased the voided volume and the maximum flow rate without affecting either the intravesical pressure or the bladder compliance. Distigmine (0.03-0.3 mg/kg, i.v.) and neostigmine (0.01-0.1 mg/kg, i.v.), both carbamate acetylcholinesterase inhibitors, while not increasing the maximum flow rate, increased the intravesical pressure at the maximum flow rate. They also decreased the bladder compliance. Bethanechol (0.1-1 mg/kg, i.v.), a muscarinic receptor agonist, decreased the voided volume and the bladder compliance but did not affect the maximum flow rate. TAK-802 did not affect the intraurethral pressure at doses of up to 0.03 mg/kg in anesthetized guinea pigs. Distigmine increased the intraurethral pressure when administered at the dose of 0.3 mg/kg, and the effect was completely abolished by pretreatment with d-tubocurarine. These results suggest that TAK-802 reinforces the bladder-voiding functions by increasing the bladder contractility without decreasing the storage function. On the other hand, carbamate acetylcholinesterase inhibitors not only deteriorate the voiding function by inducing contraction of the external urethral sphincter muscle, resulting in increasing the urethral resistance, but also cause deterioration of the storage function. Bethanechol obviously decreased the bladder capacity, possibly due to a direct contractile effect on the detrusor smooth muscle. TAK-802 may therefore be a more useful drug than either carbamate acetylcholinesterase inhibitors or muscarinic receptor agonists in the treatment of voiding dysfunction associated with impaired detrusor contractility.