No abstract available.
Colon* ; Humans* ; Substance P* ; Tetrodotoxin*

1) The author investigated whether presynaptic alpha-adrenoceptors exist in the cardioaccelerator nerves of cold-blooded animals(frog, tortoise) as in ones of in mammals. 2) Each atrial preparation of a frog, tortoise and guinea-pig produced the positive chronotropic and inotropic responces to field stimulation. Each ventricular muscle preparation of frog and tortoise produced positive inotropic responces to field stimulation. 3) Both the responces of frog atrium and the inotropic response of frog ventrice to the stimulation were abolished or markedly inhibited by the presence of tetrodotoxin, guanethidine and proparanolo. Both responses of tortoise atrium to the stimulation were markedly inhibited by propranolol and the inotropic response ventricle to the stimulation was markedly inhibited by tetrodotoxin. 4) Both responses of frog and tortoise atrium, and the inotropic response of frog and tortoise ventricle to the stimulation were not affected by clonidine and yohimbine. 5) Both responses of guinea-pig atrium to the stimulation were markedly inhibited in the presence of clonidine and this clonidine-induced inhibition was not observed in the presence of yohimbine. 6) The above results suggest that presynaptic alpha-adrenoceptors do not exist in the cardioaccelerator nerves of frog and tortoise, being different from those of mammalisn animals.
Animals* ; Clonidine ; Guanethidine ; Mammals ; Propranolol ; Tetrodotoxin ; Yohimbine

Tetrodotoxin is a neurotoxin, so gastrointestinal symptoms are very rare ; these described in the literature are merely nausea and vomiting. Severe complications in the gastrointestinal tract caused by tetrodotoxin have not been radiologically reported. US and CT show thickening of the gastric wall and contraction of the lumen, andupper gastrointestinal series show shortening, lobulation and irregularity of the lesser and greater curevature ofthe body and antrum similar to the findings of corrosive gastritis.
Barium ; Eggs* ; Gastritis* ; Gastrointestinal Tract ; Nausea ; Ovum* ; Tetraodontiformes* ; Tetrodotoxin ; Vomiting

BACKGROUND/AIMS: DA-9701 significantly improved gastric accommodation by increasing the postprandial gastric volume. In this study, we investigated how DA-9701 affects the rat gastric fundus relaxation. METHODS: Gastric fundus muscle strips (9 longitudinal and 7 circular muscles) were obtained from rats. Electrical field stimulation (EFS) was performed at various frequencies (1, 5, 10 and 20 Hz) and train durations (1, 5, 10 and 20 seconds) to select optimal condition for experiments. Isometric force measurements were performed in response to EFS. Peak and nadir were observed during the first 1 minute after initiation of EFS in control state and after sequential addition of atropine (1 microM), DA-9701 (0.5, 5, 25 and 50 microg), N-nitro-L-arginine (L-NNA, 100 microM), MRS2500 (1 microM) and tetrodotoxin (TTX, 1 microM) to the organ bath. RESULTS: The optimal frequency and duration of EFS to evoke nerve-mediated relaxation was determined as 5 Hz for 10 seconds. Addition of L-NNA in the presence of atropine and DA-9701 (50 microg) decreased nadir by inhibiting relaxation from -0.054 +/- 0.021 g to -0.022 +/- 0.015 g (P = 0.026) in longitudinal muscles. However, subsequent application of MRS2500 in the presence of atropine, DA-9701 (50 microg) and L-NNA did not affect nadir. In circular muscles, subsequent addition of L-NNA and MRS2500 in the presence of atropine and DA-9701 (50 microg) did not show significant change of nadir. CONCLUSIONS: Our data suggest that the effect of DA-9701 on the rat gastric fundus relaxation is mainly mediated by nitrergic rather than purinergic pathway.
Animals ; Atropine ; Baths ; Gastric Fundus* ; Muscles ; Rats* ; Relaxation* ; Tetrodotoxin

Higenamine is known to possess stimulatory activity on beta-receptor of the heart. Chronotropic actions of higenamic were studied in spontaneously beating right atrial muscle isolated from rabbits. The frequency of spontaneous beating and the relative threshold voltage of the right atrium were examined. The relative threshold voltage was defined as the minimal voltage of the given impulse above which the right atrium could be paced at the frequency of 20% of higenamine was also observed. Higenamine caused the postive chronotropic effect. This response became prominent as the ca2+ concentration in the bathing solution lowered. When tetrodotoxin was added to the bathing solution, the effect of higenemine altered and became similar to that of epinephrine. Higenamine reduced the relative threshold voltage of the right atrium in the bathing solution with [ca2+] of 0.5mM. Such effect was abolished by tetrodotoxin. The effects of verapamill on the spontaneous rate and the relativel threshold voltage were inhibited by higenemine. The above results suggest that, aithough the main action og higenamine is on the Ca channel, higenamine also have a minor effect of augmenting the Na channel.
Baths ; Epinephrine ; Heart ; Heart Atria* ; Heart Rate ; Rabbits ; Tetrodotoxin ; Verapamil

Ingestion of the eyes and many of the internal organs of puffer fish can result in severe and potentially lethal intoxication, but there is little available information regarding the results of grade IV tetrodotoxin (TTX) intoxication. Thus, we retrospectively reviewed and analyzed the clinical characteristics of ventilator therapy patients and those suffering respiratory failure after ingestion of TTX from puffer fish, who were admitted to our hospital from January 2002 to May 2011. Of the total patients evaluated, we observed seven cases of Fukuda classification grade IV TTX poisoning. All patients were discharged without any complications within 5-26 days after admission.
Eating ; Eye ; Humans ; Respiratory Insufficiency ; Retrospective Studies ; Stress, Psychological ; Tetraodontiformes ; Tetrodotoxin ; Ventilators, Mechanical

This study examined the acute effects of ethanol (EtOH) on the firing patterns of Purkinje cells (PCs) using an intracellular recording in slice preparation of rat cerebellum. The experiments were performed in sagittal cerebellar slices (400 microm) of adult Sprague-Dawley rats (80-100g). Ethanol was applied by a bath superfusion with a known concentration expressed as the percentage of solution by volume (v/v) at 0.1, 0.5, 1, 2, and 4%. The result of the Chi-square test illustrated that the firing patterns were altered significantly after EtOH (p=0.007). However, the firing patterns that were altered by EtOH application were not affected by EtOH concentration (p= 0.1296). Among the 54 PCs tested, 30 PCs did not display any spontaneous firing activity and 24 PCs displayed spontaneous spike activity, either spiking in the simple manner (n=14) or cyclicly oscillating (n=10). In the presence of EtOH, 31 PCs were quiet, 22 PCs exhibited simple spiking activity and 1 PC continued to oscillate. Most PCs that displayed spontaneous activity before EtOH application progressively slowed their spike activity after EtOH superfusion. Especially, it was evident that 9 out of 10 oscillating PCs stopped their regular cyclic activity. In addition, 9 out of 14 PCs that displayed simple spike activity ceased to fire after EtOH application. Eleven out of 30 quiet PCs began to fire irregularly after EtOH application and this phenomenon usually occurred with membrane depolarization. EtOH induced spontaneous activity in 36.7% (11/30) of the quiescent PCs. In conclusion, there was differential EtOH sensitivity in the vitro slice preparation. EtOH depressed the endogenously generated spontaneous activity, especially the oscillatory firing activity. In contrast, the silent PCs were excited after EtOH application. Since this differential sensitivity persists in the presence of tetrodotoxin (TTX), it is suggested that this differential sensitivity is peculiar to the PCs.
Animal ; Ethanol/*toxicity ; In Vitro ; Purkinje Cells/*drug effects/physiology ; Rats ; Rats, Sprague-Dawley ; Tetrodotoxin/pharmacology

PURPOSE: We conducted this study in order to determine clinical features and prognostic factors in adults with acute tetrodotoxin (TTX) poisoning caused by ingestion of puffer fish. METHODS: In this retrospective study, 107 patients were diagnosed with TTX poisoning. The subjects were divided into two groups according to duration of treatment; Group I, patients were discharged within 48 hours (n=76, 71.0%), Group II patients were discharged after more than 48 hours (n=31, 29.0%). Group II was subsequently divided into two subgroups [IIa (n=12, 11.2%), IIb (n=19, 17.8%)] according to the need for mechanical ventilation support. RESULTS: In multivariable logistic regression analysis, the predictors of the need for treatment over 48 hours were dizziness (odds ratio [OR], 4.72; 95% confidence intervals [CI], 1.59-12.83), time interval between onset of symptom and ingestion (OR, 0.56; 95% CI, 0.16-0.97), PaCO2<35 mmHg (OR, 8.37; 95% CI, 2.37-23.59). In addition, predictors of the need for mechanical ventilation were a time interval between onset of symptoms and ingestion (OR, 0.54; 95% CI, 0.11-0.96) and PaCO2<35 mmHg (OR, 5.65; 95% CI, 1.96-18.66). CONCLUSION: Overall, dizziness, time interval between onset of symptoms and ingestion, DeltaDBP and PaCO2<35 mmHg predict the need for treatment over 48 hours, time interval between onset of symptoms and ingestion and PaCO2<35 mmHg predict the need for mechanical ventilation support after acute TTX poisoning.
Adult* ; Dizziness ; Eating ; Humans ; Logistic Models ; Poisoning* ; Respiration, Artificial ; Retrospective Studies ; Tetraodontiformes* ; Tetrodotoxin

In the present study, we used in vitro whole-cell patch-clamp technique to record and analyze oscillatory activity of neurons in the optic tectum of Xenopus. Two patterns of subthreshold oscillations were induced by long-term depolarizing current pulses. One of the oscillating patterns occurred without a slow inward current (SIC); the other was superimposed on the SIC. The subthreshold oscillations were induced by depolarization in 48% of the recorded neurons. Both the oscillations and the SIC were tetrodotoxin (TTX)-resistant, but neither occurred when the slices were immersed in Ca(2+) free solutions. The evocation of the oscillations was voltage-sensitive: only when the initial membrane potentials of the neurons were held at -40 mV or -50 mV, 10 mV depolarization could induce the subthreshold oscillations. The amplitude and duration of the SIC depended on the level of the initial membrane potential. The subthreshold oscillations might play an important role in the physiological and behavioral functions of frogs, e.g. pattern discrimination, prey recognition, avoiding behavior etc., furthermore, these oscillations might play roles in the integration of neural activity in both mammals and non-mammalian vertebrates.
Animals ; Cell Polarity ; Membrane Potentials ; Neurons ; cytology ; Patch-Clamp Techniques ; Tetrodotoxin ; pharmacology ; Xenopus

OBJECTIVETo develop a rapid hilic ultra performance liquid chromatography (UPLC)-mass spectrum (MS)/MS method for determination of tetrodotoxin in seafood.

METHODSThe sample of muscle and liver of puffer fish and nassarius were extracted with aqueous solution containing 0.2% (V/V) acetic acid (the extract of liver must be purified through HLB cartridge), and then cleanup of extract was accomplished by solid-phase extraction with a graphitized carbon black cartridge. The analysis of tetrodotoxin was carried out on a chromatographic column (Acquity UPLC BEH Amide, 100 mm×2.1 mm×1.7 µm) with gradient elution of 95% (V/V) acetonitrile-H2O both containing 0.1% (V/V) formic acid and 2.0 mmol/L ammonium formate, and detected by positive electrospray ionization tandem mass spectrometry in the multiple reaction monitoring (MRM) mode, and quantified by matrix-match standard solution.

RESULTSThe calibration curves were linear in the range of 30 - 10 000, 50 - 10 000 and 30 - 10 000 µg/kg of tetradotoxin in muscle and liver of puffer fish and in muscle of nassarius, respectively. The correlation coefficients were within 0.9963 - 0.9990. The limits of detection were 10, 20 and 10 µg/kg, and that of quantitation were 30, 50 and 30 µg/kg for muscle and liver of puffer fish and muscle of nassarius, respectively. The average recoveries were 81.5% - 93.1%, 82.3% - 106.0% and 83.5% - 95.2% for tetrodotoxin spiked in muscle and liver of puffer fish and in muscle of nassarius, respectively, with relative standard deviation (RSD) of 2.3% - 11%, 4.3% - 14.0% and 3.5% - 13.0% (n = 6).

CONCLUSIONThe method was simple, accurate and sensitive, and could be successfully applied to the measurement of tetrodotoxin in puffer fish and nassarius.