Effect of maintaining frog sartorius muscles in a number of chloral hydrate solutions on their resistance to the harmful action of this substance]

A study was made of the effect of maintenance of m. sartorius of the grass frog in several concentrations of chloral hydrate (0.0025 M, 0.005 M, 0.008 M, 0.01 M, and 0.02 M) on their resistance to 0.08 M concentration of this substance. The increase in resistance of muscles was observed after the maintenance in all the several concentrations of the agent except one (0.02 M). The increase in resistance was maximal after a 5 minute maintenance in any concentration. The optimal dose of the effect was a 5 minute maintenance in 0.005 M chloral hydrate solution. In this case the increase in resistance to 0.08 chloral hydrate was the highest (about 23%). The study of the effect of optimal doses on the resistance of muscle tissue to 0.12 M solution fluoride, 3.48 M ethyl alcohol and to 36 derees showed a statistically significant increase in resistance from 22.7 to 39.4%.     

Differential Effects of Chloral Hydrate and Pentobarbital Sodium on a Cocaine Level and Its Catecholamine Response in the Medial Prefrontal Cortex: A Comparison with Conscious Rats

Abstract: Adult male Sprague-Dawley rats anesthetized with chloral hydrate and pentobarbital sodium were used as two different treatment groups. Conscious rats were used as a control group. By using baseline (precocaine) concentration as 100%, after cocaine administration (3.0 mg/kg i.v.), the maximal dopamine (DA) increase occurring at the first microdialysis collection period (20 min) in the medial prefrontal cortex was 299 ± 46% for the chloral hydrate group, 168 ± 12% for the pentobarbital sodium group, and 325 ± 23% for the conscious group. At the same time, norepinephrine (NA) increases reached a maximum and were 162 ± 20%, 100 ± 5%, and 141 ± 17%, respectively. The maximal changes of DA and NA in the chloral hydrate group and in the control group were both significantly higher than that in the pentobarbital sodium group. Meanwhile, the cocaine concentration was higher over a 100-min period of time in the chloral hydrate group when compared with the pentobarbital group and the control group. The peak cocaine concentration in dialysate occurred in the same time slot of maximal DA and NA responses, which were 0.65 ± 0.08, 0.30 ± 0.02, and 0.41 ± 0.05 µ M , respectively. Anesthetics suppress the pharmacologic response of neurons, which may explain the difference in catecholamine response between the pentobarbital sodium and the conscious groups. Conversely, because there was no significant difference in DA and NA response between the chloral hydrate group and the conscious group, it may possibly be due to the balancing effect between the higher existing cocaine concentration and the anesthetic suppression on pharmacological response of neurons in the chloral hydrate group. The effect of guide cannula implantation on the cocaine-induced catecholamine response was also evaluated.     

Effect of low doses of sodium fluoride on the resistance of m. sartorius of frog to the injurious action of this substance]

A study was made of the effect of the preliminary maintenance of m. sartorius in 0.025 M NaF on their resistance to the injurious dose (0.12 M NaF). In the winter frogs, the muscle resistance to 0.12 M NaF increased statistically significant after 10 and 15 minutes maintenance in 0.25 M NaF by 27.8 and 34.6%, respectively. In spring frogs, the resistance increases as soon as after a 5 minutes preincubation by 22.5% (P less than 0.05). A 15 minutes incubation produced a similar effect as that observed in winter (32.8% P less than 0.05) A 15 minutes maintenance of muscles in a weak solution of NaF while increasing their resistance to the inhibitor was found to decrease their resistance to an injurious ethanol solution (3.48 M), and to 36 degrees, by 58 and 53%, respectively.     

Effect of weak doses of ethyl alcohol on the resistance of the frog sartorius to injurious concentrations of that substance]

A study was made of the effect of preliminary maintenance of m. sartorius of the grass frog in 0.87 M and 1.09 M ethyl alcohol on their resistance to 3.48 M ethyl alcohol. The maintenance of muscle tissue in 0.87 M and 1.09 M ethyl alcohol for periods, ranging from 15 min. to 2 hours, in different series of experiments led to the increase in its resistance to 3.48 M alcohol by 11--24% as compared with the initial one. The value of increase in resistance depended on the concentration of the agent studied, the duration of maintenance, and of the season. A study of non-specificity of the adaptive effect of low alcohol decreased their resistance to 0.12 M NaF by 33.3% (P less than 0.05) The same concentration of ethyl alcohol applied for periods from 15 mintes to 2 hours either caused no change or decreased significantly the resistance of muscle tissue to the temperature 36 degrees C. This effect of decrease in resistance was even more significant when the resistance to 38 degrees C was challenged. The range of individual variability of resistance of muscles to 3.48 M alcohol and 36 degrees showns that its values in the control and in the experiment are similar.     

Spontaneous and induced activation of rat oocytes

Ovulated rat oocytes undergo spontaneous activation during in vitro culture. After extrusion of the second polar body, they do not enter interphase but are arrested again in next metaphase-like stage (M III arrest). The present study demonstrates that puromycin and chloral hydrate can trigger transition to interphase of metaphase II and spontaneously (incompletely) activated rat oocytes. The response of oocytes to these activators depends on their stage at the time of application of a stimulus. Metaphase II oocytes enter interphase at 86.8% when treated with puromycin and in 28.7% after chloral hydrate activation. Oocytes activated with chloral hydrate at the time of spontaneously induced anaphase II enter interphase at 64.8%, but after reaching the stage of telophase II their capability to shift to interphase is again low (28.8%). Finally, M III oocytes cannot be forced to enter interphase by either chloral hydrate or puromycin treatment. This study shows that resumption of the second meiotic division and transition to interphase--the two processes that normally occur in succession as a response to oocyte activatin--can be experimentally separated.     

Effect of Chloral Hydrate on Methane and Propionic Acid in the Rumen

Methane production from pyruvate by mixed rumen bacteria in vitro was nearly totally inhibited by chloral hydrate (0.1 mumole/ml of incubation fluid). This effect was accompanied by an accumulation of gaseous hydrogen and an increase in propionic acid production. Infusion of chloral hydrate (4 g/day) into the rumen of a sheep produced the same effects. Evidence is presented for a direct toxic effect of chloral hydrate upon methane bacteria. Results are discussed in terms of fermentation balances.     

Dynamics of various integral characteristics of individual changes in ethanol resistance in isolated muscles of grass frog]

A study was made of the dynamics of the mean level of toxic ethyl alcohol (EA) (3.5 M) resistance, of the correlation between the initial individual level of this resistance and the value and shifting direction of the level, and of the pattern of correlation between levels of resistance in the pair sartoria muscles and variability of resistance level in muscles, kept in EA subtoxic solutions (0.87 and 1.09 M) for 240 min. Two-phase changes in the mean level of resistance in muscles were revealed that involved its increase by 20% within 60 min of maintenance in both EA concentrations, and followed by a decrease of this level by the end of observation. On the first steps of muscle maintenance in EA subtoxic solutions, a negative correlation was noticed between the initial level of resistance and the value and direction of its shifting, in addition to narrowing the range of variability of this level in muscles. All these events were accompanied by a decrease or fluctuations in the correlation coefficient between levels of resistance in the pair muscles. By the end of the experiment, the range of variability of the level of resistance was seen to increase, and the earlier negative correlation between the initial individual level of resistance and the value and direction of its shifting appeared to change for a positive one. Both processes preceded the decrease in the mean level of muscle resistance.     

Effect of anesthetics on efficiency of remote ischemic preconditioning

Remote ischemic preconditioning of hind limbs (RIPC) is an effective method for preventing brain injury resulting from ischemia. However, in numerous studies RIPC has been used on the background of administered anesthetics, which also could exhibit neuroprotective properties. Therefore, investigation of the signaling pathways triggered by RIPC and the effect of anesthetics is important. In this study, we explored the effect of anesthetics (chloral hydrate and Zoletil) on the ability of RIPC to protect the brain from injury caused by ischemia and reperfusion. We found that RIPC without anesthesia resulted in statistically significant decrease in neurological deficit 24 h after ischemia, but did not affect the volume of brain injury. Administration of chloral hydrate or Zoletil one day prior to brain ischemia produced a preconditioning effect by their own, decreasing the degree of neurological deficit and lowering the volume of infarct with the use of Zoletil. The protective effects observed after RIPC with chloral hydrate or Zoletil were similar to those observed when only the respective anesthetic was used. RIPC was accompanied by significant increase in the level of brain proteins associated with the induction of ischemic tolerance such as pGSK-3β, BDNF, and HSP70. However, Zoletil did not affect the level of these proteins 24 h after injection, and chloral hydrate caused increase of only pGSK-3β. We conclude that RIPC, chloral hydrate, and Zoletil produce a significant neuroprotective effect, but the simultaneous use of anesthetics with RIPC does not enhance the degree of neuroprotection.     

Differential effects of chloral hydrate- and ketamine/xylazine-induced anesthesia by the s.c. route

The proper use of anesthetics in animal experimentation has been intensively studied. In this study we compared the use of chloral hydrate (500 mg kg(-1)) and ketamine (167 mg kg(-1)) combined with xylazine (33 mg kg(-1)) by the s.c. route in male Wistar rats. Chloral hydrate and ketamine/xylazine produced a depth of anesthesia and analgesia sufficient for surgical procedures. The decrease of systolic and diastolic blood pressure was of a higher magnitude in rats anesthetized with chloral hydrate than with ketamine/xylazine. The initial microvascular diameter and blood flow velocity did not differ between both agents. On the other hand, ketamine/xylazine reduced the heart rate more intensively than chloral hydrate. Both anesthetics promoted an increase in arterial pCO(2) and a decrease in pH levels compared to unanesthetized animals. The blood glucose levels were of a higher magnitude in rats after ketamine/xylazine anesthesia than after chloral hydrate. In mesenteric arterioles studied in vivo, ketamine/xylazine anesthesia reduced the constrictive effect of noradrenaline and the dilator effect of bradykinin. However, both anesthetics did not modify the vasodilator effect promoted by acetylcholine. Based on our data, we concluded that both anesthetics alter metabolic and hemodynamic parameters, however the use of chloral hydrate in studies of microvascular reactivity in vivo is more appropriate since ketamine/xylazine reduces the responses to vasoactive agents and increases blood glucose levels.     

Conformational transition within the A-form of complementary nucleic acids in solution]

Circular dichroic spectra of A-DNA in 78% ethanol and of tRNA in water and ethanol solutions have been studied at different concentrations of NaCl. An increase in the Na+ concentration from 0.5.10(-4) M to 5.10(-4) M results in a shift of the positive CD band at 264 nm of the A-DNA to a longer wavelength, 272 nm. Simultaneously, the magnitude of the 210 nm band decreases. By contrast in the case of tRNA in water solution an increase in NaCl content results in straight opposite shifts of the CD spectra. This opposite behaviour is shown to the due to a difference in ions effects in water and water-ethanol solutions, since tRNA in the ethanol solution behaves in the same way as A-DNA does in 78% ethanol. We suppose that in aqueous solution in increase in the cation concentration would stabilize the helical conformations with progressively decreasing narrow groove, i. e. more wound. At a high concentration of ethanol (60--80%) the formation of specific complex between the hydrated cations and the double-stranded regions should be taken into consideration. Thus, the hydrated cations may insert into the deep groove exerting the opposite effect of unwinding.     

Block Staining of Nervous Tissue with Silver: III. Pericellular end-bulbs or boutons

Fixation in 20 to 40% pyridin or in 10% chloral hydrate followed by 10 to 40% pyridin gave the most consistent staining of pericellular structures in the spinal cord of cat. Chloral hydrate perfusion and soaking followed by ammoniated alcohol (Hoff's application of Cajal's method) was uniformly successful only when pyrogallol instead of hydroquinone was used as a reducing agent. Perfusion of the animal with chloral hydrate gave a rather questionable degree of improvement over fixation by simple soaking. The difficulty in selecting a routine procedure as the “best” became apparent when no single experimental variation was outstandingly superior in all animals.     

Notes on Technic

Fixation in 20 to 40% pyridin or in 10% chloral hydrate followed by 10 to 40% pyridin gave the most consistent staining of pericellular structures in the spinal cord of cat. Chloral hydrate perfusion and soaking followed by ammoniated alcohol (Hoff's application of Cajal's method) was uniformly successful only when pyrogallol instead of hydroquinone was used as a reducing agent. Perfusion of the animal with chloral hydrate gave a rather questionable degree of improvement over fixation by simple soaking. The difficulty in selecting a routine procedure as the “best” became apparent when no single experimental variation was outstandingly superior in all animals.     

The effects of anaesthesia and hypothermia on interstitial concentrations of acetylcholine and choline in rat striatum

The effects of the general anaesthetics pentobarbital, chloral hydrate, and halothane on interstitial concentrations of acetylcholine (ACh) in rat striatum were determined using in vivo microdialysis. All 3 anaesthetics decreased ACh. Emergence from anaesthesia coincided with a recovery of ACh to about 80% of basal values. Pentobarbital increased choline in a profile that was the mirror image of ACh. Chloral hydrate had a biphasic effect on choline, consisting of a shortlasting (20 min) initial decrease followed by an increase. When halothane anaesthetized rats were subjected to forced hypothermia by placing them on ice for 30 min, ACh release was further depressed whereas choline was greatly increased. These finding demonstrate that general anaesthetics decrease extracellular concentrations of ACh in the rat striatum and that this effect can be exacerbated by hypothermia.     

Dependence of the rate of development of Zenker's necrosis in the fibers of the frog sartorius muscle on the concentration of chloral hydrate, urea and urethane

The spreading necrosis in dissected m. sartorius of Rana temporaria changes its speed in the phasic mode in relation to the concentrations of chloral hydrate, urea and uretan, added to the Ringer solution. The number and size of the phases are also dependent on the temperature and the initial physiological state. The concentrations of the above chemicals decelerating necrosis are 2-4 times less than those that increase the survival time of isolated muscles.     

Differentiation of Mastocyte Granules by Tartrazine Counterstaining After the Periodic Acid-Schiff Procedure

When the periodic acid-Schiff stain is followed by a counterstain of 1% tartrazine O in 1% acetic acid, mastocyte granules turn to a brick-orange color. Pharyngeal and intestinal mucus remain unchanged and gastric mucus is only slightly affected. The best results were obtained after fixation in Cajal-De Castro fluid (95% ethanol, 50 ml; distilled water, 50 ml; chloral hydrate, 5-10 gm; and nitric acid, 5 ml).     

On the contribution of the acrylate pathway to the formation of propionate from lactate in the rumen of cattle

The effect of chloral hydrate, an inhibitor of methanogenesis, on the participation of the acrylate pathway in the formation of propionate from lactate in rumen contents of cattle was studied in vitro. Addition of chloral hydrate resulted in only a small stimulation of the acrylate pathway, much lower than the stimulation of propionate production by chloral hydrate. This means that the flux of carbon through both the acrylate and the dicarboxylic acid pathway is increased during chloral hydrate feeding.The influence of time of sampling after feeding on the contribution of the acrylate pathway was studied in a separate experiment. A marked drop in the participation of the acrylate pathway in propionate formation from lactate during at least 2 h after feeding was observed, whereafter a rapid rise to prefeeding levels occurred.     

Additional components of bovine heart cytochrome c oxidase demonstrated by high-resolution polyacrylamide-gel electrophoresis in the presence of chloral hydrate.

We have shown that aq. 100% (w/v) chloral hydrate (2,2,2-trichloroethane-1,1-diol) dissociates bovine heart cytochrome c oxidase. We have developed new procedures of polyacrylamide-gel electrophoresis in the presence of chloral hydrate that permit variation in the pH of the separation, and, by using these procedures, we have observed 15 components in preparations of the enzyme. This number contrasts with the eight bands that were seen on electrophoresis in the presence of SDS (sodium dodecyl sulphate) and urea. We have isolated material from these eight bands and have characterized each by electrophoresis in the presence of chloral hydrate. Twelve of the fifteen components that were seen by electrophoresis in chloral hydrate were identified as constituents of the eight bands seen by electrophoresis in the presence of SDS and urea. Two-dimensional electrophoretic separations confirmed these identifications ans showed that the other three components which were resolved as discrete bands by electrophoresis in the presence of chloral hydrate appeared to be diffusely present in the electrophoretic separations performed in the presence of SDS and urea, which suggested anomalous behaviour in that detergent. Trypsin treatment of cytochrome c oxidase caused total loss, as observed by electrophoretic separations in the presence of chloral hydrate, of a number of components. The trypsin-sensitive components included all of those that behaved anomalously in the presence of SDS and urea. Chloral hydrate is a potent non-ionic dissociating agent for cytochrome c oxidase and its use in polyacrylamide-gel electrophoresis, with variation in the pH of the gel, permits charge-dependent separations that should have general application in the analysis of membrane proteins.     

A common origin of voltage noise and generator potentials in statocyst hair cells

Voltage noise, generator potentials, and hair movements in the Hermissenda statocyst were analyzed. Motile hairs on the cyst's luminal surface moved as rods through +/- 10 degrees Hz when free and at 7 Hz when loaded with the weight of the statoconia (at 120 degrees C). For hair cells oriented opposite to a centrifugal force vector, rotation caused depolarization and increase of voltage noise variance. The depolarizing generator potential and the increase in voltage noise variance were similarly reduced by perfusion with zero external sodium or chloral hydrate. Cooling, perfusion with zero external sodium or chloral hydrate reduced the movement frequencies of the hairs but increased their range of motion. The same treatments reduced voltage noise variance and increased input resistance of the hair cell membrane. The results indicate that voltage noise and hair cell generator potential have a common origin: exertion of force on statocyst hairs by the weight of statoconia. The collision of statoconia with the motile hairs, not the hairs' bending, produces most of the voltage noise.     

水合氯醛、乌拉坦及其1:1 混合液在SD 大鼠麻醉中的效果比较及应用

目的:比较水合氯醛、乌拉坦及其1:1混合液在SD大鼠麻醉中的效果并进一步在大鼠模型制备的麻醉中检验其效果。方法:分别采用不同剂量的水合氯醛和乌拉坦及其1:1混合液进行麻醉实验,比较其麻醉起效时间、维持时间和死亡率,并将相同剂量的1:1混合液应用于SD大鼠模型制作时的麻醉中,比较其与非模型组之间的差异。结果:水合氯醛和乌拉坦混合液麻醉大鼠的起效时间2.5±1.5分钟,与单用水合氯醛无差异(P>0.05),比单用乌拉坦起效时间短(P<0.05);维持时间107.4±4.1分钟,比单用水合氯醛、乌拉坦长(P<0.01);麻醉死亡率比单用水合氯醛低,总死亡率比单用水合氯醛、乌拉坦低。模型组大鼠的麻醉起效时间2.9±1.6分钟,维持时间108.9±4.4分钟,零麻醉死亡率,总死亡率为2.5%;与1:1混合液非模型组的麻醉效果没有明显差异。结论:水合氯醛+乌拉坦1:1混合液麻醉效果好、起效快、死亡率极低,适合用于2小时左右的SD大鼠手术或模型制作。     

Voltage noise accompanying chemically-induced depolarization of insect photoreceptors

Intracellular potentials are recorded from photoreceptors in a superfused preparation of the retina of a locust compound eye. Chloral hydrate and alkyl alcohols induce a rapid, superfusing reversible depolarization of these photoreceptors when dissolved in the saline. Analysis of voltage noise accompanying depolarization by chloral hydrate suggests that depolarizing ionic pathways are opened briefly and randomly in time in the photoreceptor membranes. This conclusion is supported by measurements of the cell resistance and of voltage noise amplitude as a function of membrane potential. Replacement of superfusate sodium by choline reversibly reduces the effects of chloral hydrate, suggesting that the ionic pathways opened are permeable by sodium. The voltage noise induced by chloral hydrate is compared to that during depolarization by steady illumination of the same cell. As the illumination intensity is increased, the amplitude and the shape of the power spectrum of light-induced voltage noise approach those of drug-induced noise at the same depolarization level. The possibility that these phenomena represent alterations in the mechanism of phototransduction is discussed.