• Asian Pacific Journal of Cancer Prevention
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• v.16 no.2
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• pp.831-836
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• 2015

Tumor fluid accumulation occurs in both human cancer and experimental tumor models. Solid tumors show a tendency to tumor fluid accumulation because of their anatomical and physiological features and this may be influenced by molecular factors. Fluid accumulation in the peri-tumor area also occurs in the Dunning model of rat prostate cancer as the tumor grows. In this study, the effects of tumor fluids that were obtained from Dunning prostate tumor-bearing Copenhagen rats on the strongly metastatic MAT-LyLu cell line were investigatedby examining the cell's migration and tumor fluid's toxicity and the kinetic parameters such as cell proliferation, mitotic index, and labelling index. In this research, tumor fluids were obtained from rats injected with $2{\times}10^5$ MAT-LyLu cells and treated with saline solution, and 200 nM tetrodotoxin (TTX), highly specific sodium channel blocker was used. Sterilized tumor fluids were added to medium of MAT-LyLu cells with the proportion of 20% in vitro. Consequently, it was demonstrated that Dunning rat prostate tumor fluid significantly inhibited proliferation (up to 50%), mitotic index, and labeling index of MAT-LyLu cells (up to 75%) (p<0.05) but stimulated the motility of the cells in vitro.

• KSBB Journal
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• v.13 no.1
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• pp.71-76
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• 1998

Tissue biosensor for mearsuring sodium channel blockers, such tetrodotoxin(TTX), saxitoxin (STX) and paralytic shellfish poisoning(PSP) consisted of frog bladder membrane, and $Na^{+}$ electrode. The proposed biosensor was applied to determine Chinese drug and dry or wet Porphyra yezonesis $Na^{+}$ channel blockers below the detection limit of the standard mouse bio-assay while the observed detection limit didn't cause human poisoning. The proposed biosensor system may be used for future $Na^{+}$ channel blockers monitoring within the marine environment.

• Biomolecules & Therapeutics
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• v.3 no.2
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• pp.149-153
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• 1995

Nitric oxide (NO) has been regarded as one of the neurotransmitters of nonadrenergic, noncholinergic (NANC) nerve stimulation in rabbit corpus cavernosum, rat gastric fundus and human intestine. PIANO (photo-induced adequate nitric oxide) is a very useful tool to investige the role of NO in various smooth muscles where NO is a mediator. The present study was undertaken to compare the physiological responses of the rat gastric smooth muscle in response to NANC nerve stimulation and to PIANO. Photolysis of L-NAME, D-NAME and streptozotocin (572) by UV light in the bathing medium caused relaxation of rat gastric fungus that contracted with carbachol, but was resistant to tetrodotoxin (TTX, 1 $\mu$M). Electrical stimulation (20 V, 2~32 Hz, 0.2 msec, 10s) of the gastric fundus, in the presence of atropine and guanethidine, induced frequency-dependent, TTX-sensitive relaxation. Sodium nitroprusside (1 nM-10 $\mu$M), a NO donor, mimicked the relaxations observed after NANC-stimulation or PIANO. Furthermore, PIANO caused UV light exposure time-dependent increase of CGMP in rat gastric fungus strips. These results provide another evidence indirectly that NO is one of the mediators of the NANC inhibitory nerve stimulation in the rat gastric fundus.

• Korean Journal of Veterinary Research
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• v.35 no.2
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• pp.237-243
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• 1995

The effects of various autonomic blocking agents to perivascular nerve stimulation were investigated on isolated coronary artery of pig. 1. The magnitude of contractile response to perivascular nerve stimulation increased with increasing frequency(280Hz) of stimulation. 2. The contractions to perivascular nerve stimulation(40V, 40Hz, 0.5msec, 1min) were increased by pretreatment of the cholinestrase inhibitor, physostigmine. 3. The contraction to perivascular nerve stimulation(40V, 40Hz, 0.5msec, 1min) was antagonised by the muscarinic antagonist, atropine. 4. The contraction to perivascular nerve stimulation(40V, 40Hz, 0.5msec, 1min) was blocked by the neural blocker, tetrodotoxin. 5. The contractions to perivascular nerve stimulation(40V, 40Hz, 0.5msec, 1min) were not significantly affected by the ${\alpha}$-adrenergic antagonist, phentolamine or ${\beta}$-adrenergic antagonist, propranolol. 6. The contractile response by the acetylcholine was increased by the pretreatment of cholinestrase inhibitor, physostigmine. This findings suggest that the powerful excitatory action by the perivascular nerve stimulation may be linked to muscarinic receptor by cholinergic nerve excitation in coronary artery of pig.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.1
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• pp.1-3
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• 2003

To investigate the receptors mediating the regulation of norepinephrine (NE) release in human cerebral cortex slices, we examined the effects of opioid agonists for ${\mu}$-, ${\delta}$-, and ${\kappa}$-receptors on the high potassium (15 mM)-evoked release of [$^3H$]NE. [$^3H$]NE release induced by high potassium was calcium-dependent and tetrodotoxin-sensitive. [$D-Pen^2$, $D-Pen^5$]enkephalin (DPDPE) and deltorphin II (Delt II) inhibited the stimulated release of norepinephrine in a dose-dependent manner. However, Tyr-D-Ala-Gly-(Me)Phe-Gly-ol and U69,593 did not influence the NE release. Inhibitory effect of DPDPE and Delt-II was antagonized by naloxone, naltrindole, 7-benzylidenaltrexone and naltriben. These results suggest that both ${\delta}_1$ and ${\delta}_2$ receptors are involved in regulation of NE release in human cerebral cortex.

• International Journal of Oral Biology
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• v.42 no.2
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• pp.55-61
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• 2017

Recent studies indicate that mitochondria are an important source of reactive oxygen species (ROS) in the spinal dorsal horn. In our previous study, application of malate, a mitochondrial electron transport complex I substrate, induced a membrane depolarization, which was inhibited by pretreatment with ROS scavengers. In the present study, we used patch clamp recording in the substantia geletinosa (SG) neurons of spinal slices, to investigate the cellular mechanism of mitochondrial ROS on neuronal excitability. DNQX (an AMPA receptor antagonist) and AP5 (an NMDA receptor antagonist) decreased the malate-induced depolarization. In an external calcium free solution and addition of tetrodotoxin (TTX) for blockade of synaptic transmission, the malate-induced depolarization remained unchanged. In the presence of DNQX, AP5 and AP3 (a group I metabotropic glutamate receptor (mGluR) antagonist), glutamate depolarized the membrane potential, which was suppressed by PBN. However, oligomycin (a mitochondrial ATP synthase inhibitor) or PPADS (a P2 receptor inhibitor) did not affect the substrates-induced depolarization. These results suggest that mitochondrial substrate-induced ROS in SG neuron directly acts on the postsynaptic neuron, therefore increasing the ion influx via glutamate receptors.

• Toxicological Research
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• v.32 no.3
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• pp.215-223
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• 2016

This study is to investigate the biological, biochemical and cytotoxic effects of puffer fish (Arothron stellatus) toxin extracts under in-vitro condition. Extracted toxins from various organs of puffer fish were purified by using active charcoal column, and Bio-gel-P2 column chromatography. The lethality of toxin was tested in crabs, which consists of neurotoxic compounds. The degree of the brine shrimp lethality assay was found directly proportional to the concentration of the toxin extracts, which was well supported by hemolytic assay. The experimental results suggested that the gonad was found higher toxins than the liver and muscles. The mortality rate of brine shrimp nauplii was increased with the raise of concentrations of toxin level. Among the different doses and time dependent cytotoxic effect of human cervical carcinoma (HeLa) cells were showed $4.0{\mu}g/mL$ of toxin, which was effectively inhibited cancer cell proliferation. HPLC and TLC analysis was revealed that the A. stellatus toxin contains tetrodotoxin (TTX), related compounds 4-epi TTX and anhydro-TTX. The present results suggested that the A. stellatus contain TTX as a major and anh-TTX as a minor toxin. It could be the potential candidate in the field of anticancer drug discovery against human cervical cancer cells. The present data is confirming that the puffer fish toxin as an interesting source of novel bioactive natural compounds with potent applications in pharmacology.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.6
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• pp.1518-1524
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• 2008

Ponciri Fructus (PF), the immature fruit of Poncirus trifoliata, has been used for treatment of constipation in Korean traditional medicine. It has been reported that PF has a prokinetic effect on gastrointestinal tract, but little is known about the effect on colonic contraction. The aim of this study was to investigate the effect of PF on spontaneous contractions of proximal and distal colon in rats. The aqueous extract of PF was centrifuged and filtered and its supernatant was used for in vitro motility study. The removed colon from rats was divided into proximal and distal segments. Each segment was mounted in a 10 ml organ bath and measured the change of the spontaneous contraction with increasing dose (1, 5, 10, 50, 100, 500, $1000{\mu}g/ml$) of PF extract administration. Also the effect of PF on the spontaneous contraction was measured under treatment of atropine, acetylcholine (Ach), and tetrodotoxin (TTX). PF increased the spontaneous phasic contraction of distal colon dose dependently, but there was no change in proximal colon. The contractile response induced by PF in distal colon was lower than that of Ach and was partially blocked by atropine ($10^{-6}M$). TTX increased the spontaneous contraction and it was reinforced with Ach addition. But the extract of PF had no or little contractile effect of TTX in colon. PF increased spontaneous contractions selectively in distal colon. The prokinetic effect of PF may be due to enhancement of cholinergic related excitatory neural system.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.217-217
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• 1996

The putative role of vasoactive intestinal polypeptide (VIP) as non-adrenergic non-cholinergic (NANC) neurotransmitter has been studied in rabbit corpus cavernosum. In the presence of atropine and guanethidine the short and prolonged electrical field stimulation (EFS, 2～16 ㎐) induced a frequency-dependent relaxation which was abolished by tetrodotoxin (0.3 ${\mu}$M), a nerve conductance blocker. The neurogenic relaxant reponses were not affected in the presence of VIP-inactivating peptidase, ${\alpha}$-chymotrypsin (2 units/$m\ell$), whereas VIP-induced relaxation were completely abolished. Inhibition of nitric oxide synthase by N$\^$G/-nitro-L-arginine (10～100 ${\mu}$M) caused concentration-dependent inhibition to the neurogenic relaxant responses and at 100 ${\mu}$M the relaxations were virtually abolished. In contrast NO (3～30 ${\mu}$M) and VIP (0.001～l ${\mu}$M)-induced relaxation were unaffected. The inhibitory effect of L-NNA was reversed in the presence of L-arginine (5 mM), the precursor of the NO biosynthesis. Hemog1obin (20～60 ${\mu}$M), sequestering NO in the extracellular space, abolished the NO-evoked relaxation and also caused a concentration-dependent inhibition to the neurogenic relaxation. These observation indicate that NANC relaxation induced by prolonged EFS of rabbit corpus cavernosum is also mediated mainly by nitric oxide as same as that of short EFS, and suggest that VIP is not involved in NANC relaxation of rabbit corpus cavernosum and NO would not be produced by VIP in this tissue.

• Journal of Chest Surgery
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• v.28 no.8
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• pp.742-746
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• 1995

The present study was aimed at investigating possible transmitter mechanisms in the endothelial cell layer in regulating the tone of the vascular smooth muscle. The thoracic aorta was isolated from the anesthetized male white rabbits and its helical strips were prepared. Electrical field stimulation was delivered to platinum wire electrodes positioned parallel to the vessel segment preconstricted with phenylephrine [3.5x10-6 mol/L at a distance of 1.5-2.0 mm. The electrical stimulation [70 V, 5 msec, 0.5-200 Hz caused either relaxation only [34% or a biphasic response [prolonged relaxation following a weak and transient contraction, 66% . The relaxation response was frequency- dependent, and at 200 Hz a complete relaxation was noted. Mechanical rubbing of the endothelial layer abolished or greatly attenuated the relaxation. The relaxation was also markedly attenuated in the presence of NG-nitro- L-arginine methyl ester [10-3mol/L or procaine hydrochloride [3.5x10-4mol/L . Tetrodotoxin,guanethidine, atropine or indomethacin failed to block or enhance the relaxation response to electrical field stimulation. It is concluded that the vascular endothelium in the aorta contains diffusible substances that regulates the function of the smooth muscle layer, in which relaxation is more prominent than contraction. Their release by the electrical stimualtion in vitro may not involve classic neuronal transmitter release mechanisms or metabolism of arachidonic acids by cyclooxygenase. The release of the relaxing agents may require an increase in cytosolic calcium level. The chemical nature of the relaxant may be, to a large extent, nitric oxide.