OBJECTIVE: To explore the characteristic changes of the peripheral chorda tympanic nerve (CT) electrophysiological responses to salty stimulus and other taste stimuli in rats with the conditioned taste aversion to saltiness. METHODS: Fourteen adult SD male rats were divided into a conditioned taste aversion to salty group (CTA) and a control group (Ctrl) (n=7/group). On the first day of the experiment, rats were given a 0.1 mol/L NaCl intake for 30 min, then, the rats in CTA and Ctrl groups were injected intraperitoneally with 2 ml of 0.15 mol/L LiCl and the same amount of saline respectively. On day 2, 3 and 4, the 30 min consumption of NaCl and distilled water was measured for both groups of rats. On the 4th day after the behavioral test of that day, CT electrophysiological recording experiments were performed on CTA rats and control rats. RESULTS: Compared with the rats in Ctrl group, the electrophysiological characteristics of CT in CTA group rats did not change significantly the responses to the series of NaCl and other four basic taste stimuli (P＞0.05). The amiloride, the epithelial sodium channel blocker, strongly inhibited the response of CT to NaCl in CTA and Ctrl group rats (P＜0.01). CONCLUSION The electrophysiological responses of CT to various gustatory stimuli do not significantly change in rats after the establishment of conditional taste aversion to the saltiness.
Amiloride ; pharmacology ; Animals ; Chorda Tympani Nerve ; physiology ; Conditioning, Classical ; Electrophysiological Phenomena ; Male ; Rats ; Rats, Sprague-Dawley ; Sodium Chloride ; Taste ; physiology

Amiloride ; analogs & derivatives ; chemistry ; metabolism ; Binding Sites ; Genotype ; Hepacivirus ; genetics ; metabolism ; Humans ; Magnetic Resonance Spectroscopy ; Molecular Dynamics Simulation ; Protein Structure, Tertiary ; Viral Proteins ; antagonists & inhibitors ; metabolism

The present study was designed to investigate the characteristics of gintonin, one of components isolated from Korean Ginseng on secretion of catecholamines (CA) from the isolated perfused model of rat adrenal gland and to clarify its mechanism of action. Gintonin (1 to 30 µg/ml), perfused into an adrenal vein, markedly increased the CA secretion from the perfused rat adrenal medulla in a dose-dependent fashion. The gintonin-evoked CA secretion was greatly inhibited in the presence of chlorisondamine (1 µM, an autonomic ganglionic bloker), pirenzepine (2 µM, a muscarinic M₁ receptor antagonist), Ki14625 (10 µM, an LPA₁/₃ receptor antagonist), amiloride (1 mM, an inhibitor of Na⁺/Ca²⁺ exchanger), a nicardipine (1 µM, a voltage-dependent Ca²⁺ channel blocker), TMB-8 (1 µM, an intracellular Ca²⁺ antagonist), and perfusion of Ca²⁺-free Krebs solution with 5mM EGTA (a Ca²⁺chelater), while was not affected by sodium nitroprusside (100 µM, a nitrosovasodialtor). Interestingly, LPA (0.3~3 µM, an LPA receptor agonist) also dose-dependently enhanced the CA secretion from the adrenal medulla, but this facilitatory effect of LPA was greatly inhibited in the presence of Ki 14625 (10 µM). Moreover, acetylcholine (AC)-evoked CA secretion was greatly potentiated during the perfusion of gintonin (3 µg/ml). Taken together, these results demonstrate the first evidence that gintonin increases the CA secretion from the perfused rat adrenal medulla in a dose-dependent fashion. This facilitatory effect of gintonin seems to be associated with activation of LPA- and cholinergic-receptors, which are relevant to the cytoplasmic Ca²⁺ increase by stimulation of the Ca²⁺ influx as well as by the inhibition of Ca²⁺ uptake into the cytoplasmic Ca²⁺ stores, without the increased nitric oxide (NO). Based on these results, it is thought that gintonin, one of ginseng components, can elevate the CA secretion from adrenal medulla by regulating the Ca²⁺ mobilization for exocytosis, suggesting facilitation of cardiovascular system. Also, these findings show that gintonin might be at least one of ginseng-induced hypertensive components.
Acetylcholine ; Adrenal Glands ; Adrenal Medulla* ; Amiloride ; Animals ; Cardiovascular System ; Catecholamines ; Chlorisondamine ; Cytoplasm ; Egtazic Acid ; Exocytosis ; Ganglia, Autonomic ; Nicardipine ; Nitric Oxide ; Nitroprusside ; Panax ; Perfusion ; Pirenzepine ; Rats ; Veins

OBJECTIVETo observe the effect of amiloride on the proteinuria of the 5/6 nephrectomy rats.

METHODSTo establish the 5/6 nephrectomy rats model and divide the experiment into 3 groups, sham operated group(Sham), 5/6 nephrectomy model group(NTX) and 5/6 nephrectomy with amiloride-treated group (NTX+amiloride, n=15). The concentration of protein and mRNA of uPAR and the change of podocytes motility were detected by coomassiebluestaining, immunofluorence method and real-time PCR.

RESULTSAt second week, compared with Control group, the 24 h urine protein of NTX group was significantly increased (47.50 ± 28.05 mg vs 14.28 ± 3.8 mg, P = 0.023). There was no statistical significance in 24-hour urine protein between NTX+amiloride group and NTX group (51.56 ± 21.03 mg vs 47.50 ± 28.05 mg, P = 0.748). The same situation was also observed at the time point of 12 week, comparing with NTX group, 24-hour urine protein decreased in Sham group (188.31 ± 29.82 mg vs 21.32 ± 8.59 mg, P = 0.000) and NTX+amiloride group (188.31 ± 29.82 mg vs 121.37 ± 31.14 mg, P=0.000), with statistical significance when comparing with Sham group, the expression of uPAR mRNA in NTX group was significantly increased (9.74 ± 1.44 vs 1.01 ± 0.13, P = 0.000). In contrast, the expression of uPAR mRNA in NTX rats treated with amiloride was significantly lower than in NTX group (9.74 ± 1.44 vs 5.01 ± 1.36, P = 0.000).

CONCLUSIONAmiloride can reduce the proteinuria of the 5/6 nephrectomy rats model of transient proteinuria by inhibiting the induction of uPAR expression.

Amiloride ; pharmacology ; Animals ; Cell Movement ; Disease Models, Animal ; Nephrectomy ; Podocytes ; drug effects ; metabolism ; Proteinuria ; drug therapy ; Rats ; Real-Time Polymerase Chain Reaction ; Receptors, Urokinase Plasminogen Activator ; metabolism

Amiloride and benzamil showed antinocicepitve effects in several pain models through the inhibition of acid sensing ion channels (ASICs). However, their role in neuropathic pain has not been investigated. In this study, we investigated the effect of the intrathecal amiloride and benzamil in neuropathic pain model, and also examined the role of ASICs on modulation of neuropathic pain. Neuropathic pain was induced by L4-5 spinal nerve ligation in male Sprague-Dawley rats weighing 100-120 g, and intrathecal catheterization was performed for drug administration. The effects of amiloride and benzamil were measured by the paw-withdrawal threshold to a mechanical stimulus using the up and down method. The expression of ASICs in the spinal cord dorsal horn was also analyzed by RT-PCR. Intrathecal amiloride and benzamil significantly increased the paw withdrawal threshold in spinal nerve-ligated rats (87%+/-12% and 76%+/-14%, P=0.007 and 0.012 vs vehicle, respectively). Spinal nerve ligation increased the expression of ASIC3 in the spinal cord dorsal horn (P=0.01), and this increase was inhibited by both amiloride and benzamil (P<0.001 in both). In conclusion, intrathecal amiloride and benzamil display antinociceptive effects in the rat spinal nerve ligation model suggesting they may present an alternative pharmacological tool in the management of neuropathic pain at the spinal level.
Acid Sensing Ion Channels/genetics/metabolism ; Amiloride/*analogs & derivatives/pharmacology/*therapeutic use ; Analgesics/pharmacology/*therapeutic use ; Animals ; Disease Models, Animal ; Male ; Neuralgia/*drug therapy ; RNA, Messenger/metabolism ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; Spinal Cord/metabolism ; Transcription, Genetic/drug effects

Cells can resist and even recover from stress induced by acute hypoxia, whereas chronic hypoxia often leads to irreversible damage and eventually death. Although little is known about the response(s) to acute hypoxia in neuronal cells, alterations in ion channel activity could be preferential. This study aimed to elucidate which channel type is involved in the response to acute hypoxia in rat pheochromocytomal (PC12) cells as a neuronal cell model. Using perfusing solution saturated with 95% N2 and 5% CO2, induction of cell hypoxia was confirmed based on increased intracellular Ca2+ with diminished oxygen content in the perfusate. During acute hypoxia, one channel type with a conductance of about 30 pS (2.5 pA at -80 mV) was activated within the first 2~3 min following onset of hypoxia and was long-lived for more than 300 ms with high open probability (Po, up to 0.8). This channel was permeable to Na+ ions, but not to K+, Ca+, and Cl- ions, and was sensitively blocked by amiloride (200 nM). These characteristics and behaviors were quite similar to those of epithelial sodium channel (ENaC). RT-PCR and Western blot analyses confirmed that ENaC channel was endogenously expressed in PC12 cells. Taken together, a 30-pS ENaC-like channel was activated in response to acute hypoxia in PC12 cells. This is the first evidence of an acute hypoxia-activated Na+ channel that can contribute to depolarization of the cell.
Amiloride ; Animals ; Anoxia ; Blotting, Western ; Cell Hypoxia ; Epithelial Sodium Channels ; Ion Channels ; Ions ; Neurons ; Oxygen ; PC12 Cells ; Pheochromocytoma ; Rats

PURPOSE: The effects of amiloride on cellular toxicity caused by tissue plasminogen activator (tPA) in mouse primary retinal cells were investigated. METHODS: Primary retinal cell cultures were maintained using glial conditioned medium. Commercial tPA and L-arginine were added, and the level of cyclic guanosine monophosphate (cyclic-GMP) in the culture supernatant was assessed using an ELISA assay. We measured the cell viability of cultured retinal cells pretreated with three different concentrations of amiloride (1, 10, and 100 microm) in addition to commercial tPA or L-arginine treatment. RESULTS: After exposing the cultured mouse retinal cells to tPA plus L-arginine or L-arginine alone, cyclic-GMP concentrations were 61.9 +/- 5.1 pmole/mL and 63.1 +/- 6.1 pmole/mL, respectively. However, the control group had a significantly lower concentration of cyclic-GMP (37.2 +/- 3.4 pmole/mL, p < 0.01). The cyclic GMP-dissolved solution did not cause retinal cell death. In the control group and the group treated with 1 microm amiloride and tPA containing L-arginine, the cell viability was 43.7% and 44.5%, respectively. However, cell viability increased to 70.6% with 10 microm amiloride and 78.4% with 100 microm amiloride (p = 0.015). CONCLUSIONS: L-arginine increases intracellular cyclic-GMP and may give rise to retinal cells through this mechanism. In addition, amiloride in concentrations greater than 10 microm protects against L-arginine-induced retinal cell death.
Amiloride/*pharmacology ; Analysis of Variance ; Animals ; Arginine/toxicity ; Cell Death/drug effects ; Cells, Cultured ; Cyclic GMP/pharmacology ; Enzyme-Linked Immunosorbent Assay ; Mice ; Retina/cytology/*drug effects ; Tissue Plasminogen Activator/*toxicity

A 59-year-old woman was admitted to our hospital with polydipsia and general weakness. She had a 30-year history of bipolar disorder and was being treated with risperidone (4 mg/day) and lithium carbonate (1,200 mg/day). During her time in hospital, her urine output and serum osmolality increased, and her urine osmolality decreased. She was found to have myoglobulinuria, an elevated creatine kinase level, and abnormal renal function. Based on these findings, the patient was diagnosed with diabetes insipidus and rhabdomyolysis secondary to lithium therapy. After fluid therapy and the withdrawal of lithium, her clinical symptoms improved significantly. Her urine volume decreased gradually after treatment with amiloride. The effects of lithium on the muscle system are unknown. Hyperosmolarity caused by lithium-induced diabetes insipidus is considered a contributing factor in rhabdomyolysis.
Amiloride ; Bipolar Disorder ; Creatine Kinase ; Diabetes Insipidus ; Diabetes Insipidus, Nephrogenic ; Female ; Fluid Therapy ; Humans ; Lithium ; Lithium Carbonate ; Middle Aged ; Muscles ; Osmolar Concentration ; Polydipsia ; Rhabdomyolysis ; Risperidone

A 59-year-old woman was admitted to our hospital with polydipsia and general weakness. She had a 30-year history of bipolar disorder and was being treated with risperidone (4 mg/day) and lithium carbonate (1,200 mg/day). During her time in hospital, her urine output and serum osmolality increased, and her urine osmolality decreased. She was found to have myoglobulinuria, an elevated creatine kinase level, and abnormal renal function. Based on these findings, the patient was diagnosed with diabetes insipidus and rhabdomyolysis secondary to lithium therapy. After fluid therapy and the withdrawal of lithium, her clinical symptoms improved significantly. Her urine volume decreased gradually after treatment with amiloride. The effects of lithium on the muscle system are unknown. Hyperosmolarity caused by lithium-induced diabetes insipidus is considered a contributing factor in rhabdomyolysis.
Amiloride ; Bipolar Disorder ; Creatine Kinase ; Diabetes Insipidus ; Diabetes Insipidus, Nephrogenic ; Female ; Fluid Therapy ; Humans ; Lithium ; Lithium Carbonate ; Middle Aged ; Muscles ; Osmolar Concentration ; Polydipsia ; Rhabdomyolysis ; Risperidone

BACKGROUND/AIMS: JX-594 is an oncolytic virus derived from the Wyeth vaccinia strain that causes replication-dependent cytolysis and antitumor immunity. Starting with a cross-examination of clinical-trial samples from advanced hepatocellular carcinoma patients having high levels of aldosterone and virus amplification in JX-594 treatment, we investigated the association between virus amplification and aldosterone in human cancer cell lines. METHODS: Cell proliferation was determined by a cell-counting-kit-based colorimetric assay, and vaccinia virus quantitation was performed by quantitative polymerase chain reaction (qPCR) and a viral plaque assay. Also, the intracellular pH was measured using a pH-sensitive dye. RESULTS: Simultaneous treatment with JX-594 and aldosterone significantly increased viral replication in A2780, PC-3, and HepG2 cell lines, but not in U2OS cell lines. Furthermore, the aldosterone treatment time altered the JX-594 replication according to the cell line. The JX-594 replication peaked after 48 and 24 hours of treatment in PC-3 and HepG2 cells, respectively. qPCR showed that JX-594 entry across the plasma membrane was increased, however, the changes are not significant by the treatment. This was inhibited by treatment with spironolactone (an aldosterone-receptor inhibitor). JX-594 entry was significantly decreased by treatment with EIPA [5-(N-ethyl-N-isopropyl)amiloride; a Na+/H+-exchange inhibitor], but aldosterone significantly restored JX-594 entry even in the presence of EIPA. Intracellular alkalization was observed after aldosterone treatment but was acidified by EIPA treatment. CONCLUSIONS: Aldosterone stimulates JX-594 amplification via increased virus entry by affecting the H+ gradient.
Aldosterone/*pharmacology ; Aldosterone Antagonists/pharmacology ; Amiloride/analogs & derivatives/pharmacology ; Animals ; Carcinoma, Hepatocellular/blood/virology ; Cell Line, Tumor ; Humans ; Hydrocortisone/blood ; Hydrogen-Ion Concentration ; Liver Neoplasms/blood/virology ; Neuroprotective Agents/pharmacology ; Oncolytic Virotherapy ; Rabbits ; Spironolactone/pharmacology ; Vaccinia virus/*drug effects/genetics/metabolism/*physiology ; Virus Replication/*drug effects