Ethacrynic acid inhibits airway smooth muscle contraction in mice / 生理学报

The aim of this study was to investigate the inhibitory effect and the underlying mechanism of ethacrynic acid (EA) on the contraction in mice. BL-420S force measuring system was used to measure the tension of mouse tracheal rings. The whole cell patch clamp technique was utilized to record the channel currents of airway smooth muscle (ASM) cells. The calcium imaging system was used to determine the intracellular Ca concentration ([Ca]) in ASM cells. The results showed that EA significantly inhibited the high K (80 mmol/L) and acetylcholine (ACh, 100 µmol/L)-induced contraction of mouse tracheal rings in a dose-dependent manner. The maximal relaxation percentages were (97.02 ± 1.56)% and (85.21 ± 0.03)%, and the median effective concentrations were (40.28 ± 2.20) μmol/L and (56.22 ± 7.62) μmol/L, respectively. EA decreased the K and ACh-induced elevation of [Ca] from 0.40 ± 0.04 to 0.16 ± 0.01 and from 0.50 ± 0.01 to 0.39 ± 0.01, respectively. In addition, EA inhibited L-type voltage-dependent calcium channel (LVDCC) and store-operated calcium channel (SOCC) currents in ASM cells, and Ca influx. Moreover, EA decreased the resistance of the respiratory system (Rrs) in vivo in mice. These results indicated that EA inhibits LVDCC and SOCC, which results in termination of Ca influx and decreases of [Ca], leading to relaxation of ASM. Taken together, EA might be a potential bronchodilator.

Ethacrynic acid decreases expression of proinflammatory intestinal wall cytokines and ameliorates gastrointestinal stasis in murine postoperative ileus

OBJECTIVES: Several compounds characterized by an olefin linkage conjugated to a carbonyl group have anti-inflammatory properties. The diuretic ethacrynic acid (EA) is a compound of this type. Herein, we tested the hypothesis that ethacrynic acid can modulate the development of ileus after bowel manipulation. METHODS: Groups (n=9) of male C57Bl/6 mice underwent surgical manipulation of the small intestine using a pair of cotton-tipped applicators (MAN). Control animals (CONT) did not undergo any surgical intervention or receive treatment. MAN mice were pre- and post-treated with four intraperitoneal doses of phosphate buffered saline (PBS), EA1 (1mg/kg per dose), or EA10 (10mg/kg per dose). Gastrointestinal transit of non-absorbable FITC-labeled dextran was assessed by gavaging the mice with the tracer 24h after operation and assessing FD70 concentration 120 min later in the bowel contents from the stomach, 10 equally long segments of small intestine, cecum, and two equally long segments of colon. The geometric center for the tracer was calculated for each animal. Expression of interleukin-6 (IL-6) and inducible nitric oxide synthase (iNOS) transcripts in the ileal muscularis propria was assessed using semiquantitative reverse transcriptase-polymerase chain reaction. RESULTS: In control animals, the mean (±SE) geometric center for the transit marker was 9.89±0.47, whereas it was 4.59±0.59 for PBS-treated animals (p<0.05 vs CONT). The geometric center for pre- post treatment with low (1mg/kg) and high (10mg/kg) doses of ethacrynic acid were 7.23±0.97 and 5.15±0.57, respectively. Compared to PBS, treatment with ethacrynic acid (1mg/kg) significantly decreased manipulation-induced IL-6 and iNOS mRNA expression in the wall of the small bowel. CONCLUSIONS: Pre- and post-treatment with ethacrynic acid ameliorates ileus and modulates inflammation in the gut wall induced by bowel manipulation.

Ethacrynic Acid Inhibits Sphingosylphosphorylcholine-Induced Keratin 8 Phosphorylation and Reorganization via Transglutaminase-2 Inhibition

Sphingosylphosphorylcholine (SPC) is significantly increased in the malicious ascites of tumor patients and induces perinuclear reorganization of keratin 8 (K8) filaments in PANC-1 cells. The reorganization contributes to the viscoelasticity of metastatic cancer cells resulting in increased migration. Recently, we reported that transglutaminase-2 (Tgase-2) is involved in SPC-induced K8 phosphorylation and reorganization. However, effects of Tgase-2 inhibitors on SPC-induced K8 phosphorylation and reorganization were not clearly studied. We found that ethacrynic acid (ECA) concentration-dependently inhibited Tgase-2. Therefore, we examined the effects of ECA on SPC-induced K8 phosphorylation and reorganization. ECA concentration-dependently suppressed the SPC-induced phosphorylation and perinuclear reorganization of K8. ECA also suppressed the SPC-induced migration and invasion. SPC induced JNK activation through Tgase-2 expression and ECA suppressed the activation and expression of JNK in PANC-1 cells. These results suggested that ECA might be useful to control Tgase-2 dependent metastasis of cancer cells such as pancreatic cancer and lung cancers.

Research progress of acute kanamycin sulfate-induced deafness in guinea pig / 临床耳鼻咽喉头颈外科杂志

To present a summary of current knowledge regarding acute kanamycin sulfate-induced deafness in guinea pig, by reviewing the published literature. Animal model of acute deafness induced by a single dose of kanamycin sulfate in combination with ethacrynic acid or furosemide in guinea pig was usually used to investigate the mechanism of cochlear cell degeneration. There were different time sequences of cell degeneration of spiral ganglion cell and hair cell in different studies. The findings may result from different doses, order of two drugs administration or time point chosen. There remains scope for further research in chronic kanamycin-induced deafness, which more replicates the type of exposure to people than acute deafness.

Correlation between Dose of Ethacrynic Acid and Weight of Cat in the Cat Deafening Procedure / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Co-administration of kanamycin (KM) with the loop diuretic ethacrynic acid (EA) has been known to produce a rapid and profound hearing loss in adult animals. The objective of this study was to see if monitoring the hearing status during intravenous infusion of EA could minimalize individual variability and to evaluate the correlation between the dose of EA and the body weight (wt). MATERIALS AND METHOD: Twenty cats with the mean age of 24 weeks+/-3.7 (range, 20.6-28.3 weeks) and the mean weight of 3.27 kg+/-0.75 (range 2.4-4.75 kg) received a subcutaneous injection of KM (300 mg/kg) followed by an intravenous infusion of EA (1 mg/min). Click evoked auditory brainstem responses (ABRs) were recorded to monitor the hearing during the infusion. When the ABR thresholds rose to levels in excess of 90 dB SPL, the infusion of EA was stopped. The histopathologies for sections of apex, middle, base of cochlea were examined after 6 months. RESULTS: There was a significant positive correlation (p<.001, r2=.583) between the EA dose and body weight. Cochlear histopathology showed an absence of organ of Corti and decrease of spiral ganglion cells in the majority of cochleas, especially in the basal turn. The extent of loss of spiral ganglion cells was dependent on their distance from the round window. CONCLUSION: Monitoring the animal's hearing status during the procedure ensured that the dose of EA was optimized for individual animals. Thus, the positive correlation between the EA dose and body weight should be considered should in designing the animal models of controlled high frequency hearing loss.

Correlation between reduction of distortion product otoacoustic emission and percentage of outer hair cell missing in chinchillas / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To explore the quantitative relationship between the reduction of distortion product otoacoustic emission (DPOAE) and the percentage of outer hair cell loss.</p><p><b>METHODS</b>Coadministration of cisplatin (0.2 mg/kg) and ethacrynic acid (40 mg/kg) were used to establish a cochlear lesion model in chinchillas. DPOAE was measured before and 1 week, 2 weeks, and 3 weeks later respectively after cisplatin and ethacrynic acid treatment. Animals were terminated 3 weeks after the treatment. Cochlear surface preparations were performed, and the cochlear hair cells were counted through entire length of the cochlea. The correlation between DPOAE reduction and outer hair cell missing was analyzed using Pearson correlation analysis.</p><p><b>RESULTS</b>Cisplatin and ethacrynic acid treatment induced cochlear hair cell lesion that the outer hair cell loss in the cochlea developed in a stereotypic pattern; damage began in the base of the cochlea and progressed towards the apex. Reduction of DPOAE was relatively consistent with outer hair cells loss. On the average, 1% outer hair cells loss may result in 0.24 dB reduction in DPOAE levels. Pearson analysis showed a positive correlation between the reduction in DPOAE and missing of outer hair cells (r = 0.796, P < 0.05).</p><p><b>CONCLUSIONS</b>It may be helpful to evaluate missing percentage of outer hair cells from reduction in DPOAE levels.</p>

Effect of Growth Factors on Hearing Restoration in Deafened Animal Model / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Sensorineural hearing loss is caused by ototoxic drugs, radiation therapy, noise exposure and trauma, etc. They make irreversible changes in cochlear hair cells and degeneration of spiral ganglion neurons. It is known that neurotrophins and other growth factors have an important role in protectingcochlear hair cells and spiral ganglion neurons. We designed this study to analyze the effect of neurotrophins and growth factors delivered to the inner ear of deafened guinea pig. MATERIALS AND METHOD: Healthy 15 guinea pigs with normal Preyer's reflex were chosen, and were made deaf by infusion of kanamycin and ethacrynic acid. Myringotomy was done to both ears, normal saline injected into the left ear, and BDNF (brainderived neurotrophic factor), GDNF (glial cell derived neurotrophic factor), NT-3 (neurotrophin-3), IGF (insulin-like growth factor), EGF (epidermal growth factor), FGF (fibroblast growth factor) were injected in the right ear. RESULTS: Statistically significant hearing gain was obtained up to 35.00+/-13.78 dB in the group 1 (BDNF, GDNF, NT-3 treated group), and up to 34.0+/-5.47 dB in the group 2 (IGF treated group). However, no statistically significant hearing gain was observed in the group 3 (EGF, FGF treated group). CONCLUSION: We observed statistically important improvement of hearing threshold in the BDNF, GDNF, NT-3 treated group and IGF treated group.

Proper Use of Diuretics

Diuretics are among the most commonly used drugs. They primarily block active reabsorption of sodium at different sites in the nephron, thereby increasing urinary losses of NaCl and H2O. This ability to induce a negative fluid balance has made these drugs particularly useful in the treatment of a variety of conditions, edematous: congestive heart failure, nephrotic syndrome, liver cirrhosis, chronic renal failure, idiopathic edema, and nonedematous states: hypertension, hypercalcemia, nephrolithiasis, and syndrome of inappropriate antidiuretic hormone secretion. The diuretics are generally divided into three major classes, which are distinguished by the sites at which they impair the sodium reabsorption: loop diuretics at the thick ascending limb of the loop of Henle, thiazide-type diuretics at the distal tubule, and potassium-sparing diuretics at the cortical collecting tubule. The loop diuretics that are generally the most potent are furosemide, torasemide, and ethacrynic acid. The thiazide-type diuretics include chlorothiazide and metolazone. Spironolactone and amiloride are potassium-sparing diuretics. Diuretics should be started at an effective single dose and given intermittently with a subsequent increase in dose or frequency of administration. As a general rule, the rate of diuresis in an edematous patient should not exceed 1 to 2kg weight loss per day. In renal failure patients, loop diuretics at a higher than normal dose are required to get the desired diuretic effect because the diuretic excretion is often limited, in part due to the retention of organic anions. The patients with liver cirrhosis are responsive to spironolactone. After the administration of diuretics, even if a net diuresis is induced, the response is short-lived as a new steady state is rapidly established because the diuretic-induced sodium losses are counterbalanced by neuro-humorally mediated increases in tubular reabsorption at nondiuretic sensitive sites. This process is called compensatory antidiuresis or diuretic tolerance. Therefore sodium restriction is important when a patient is taking loop diuretics, and the concurrent use of a thiazide diuretic can inhibit downstream NaCl reabsorption, resulting in an exaggeration of diuresis. The most common side-effects are those encountered in virtually all the effective drugs: hypovolemia, hypokalemia and potassium depletion, hyperuricemia, and metabolic alkalosis. Other side-effects include hyperglycemia, hyperlipidemia, hyperuricemia, ototoxicity and sexual dysfunction. In addition, diuretics have the potential to increase the toxicity of several other agents. Nonsteroidal antiinflammatory drugs may antagonize the natriuretic effects of diuretics. The combination of potassium-sparing diuretics and angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers may result in severe hyperkalemia.

Inhibición del cotransporte de NA/K/2CI por ácido etacrínico en células aisladas del epitelio / Inhibition of the cotransport of NA/K/2C1 by ethacrynic acid in insolated cell of the ciliary epithelium of the rabbits eyes

La formación de humor acuoso es debida principalmente al transporte activo de iones específicos desde el espacio extracelular del estroma a través de la doble capa de células del epitelio ciliar hacia la cámara posterior, y este proceso conduce al flujo osmótico de agua. Estudios recientes demuestran que el ácido etacrínico (AE), una droga utilizada durante muchos años como diurético produce una disminución de la presión intraocular en ojos de monos glaucomatoso e incrementa el flujo de salida de humor acuoso en ojos de monos, orangutanes y humanos. El propósito de este trabajo fue evaluar el efecto del AE sobre los mecanismos de transporte activo de K+ en células del epitelio ciliar de ojos de conejo usando Rb como trazador. Esta droga produjo una inhibición significativa del cotransporte de Na/K/2CI (De 180 ñ 8 a 35 ñ2, P<0.05), obteniéndose un efecto inhibitorio máximo a una concentración de 10 elevado a la cinco M. No observamos efecto significativo sobre la actividad de la ATPasa de Na/K. Nuestros resultados indican que la reducción de la presión intraocular producida por el AE en animales y humanos podría deberse en gran parte a la inhibición de la actividad del Cotransporte Na/K/C1 presente en el epitelio ciliar

Avanços terapêuticos em cardiologia; Parte 2. Diureticos: estado atual em cardiologia / Therapeutic advances in cardiology; Part 2. Diuretics: up-to-date cardiology

Os diuréticos constituem-se na principal arma no tratamento da insuficiência cardíaca e da hipertensäo arterial sistêmica. Os pacientes têm uma boa e prolongada resposta com alívio da dispnéia, reduzem a pressäo venosa e a congestäo hepática. Chamamos atençäo para os efeitos adversos e o uso indevido em pacientes com edema e obesidade