Precurarización con rocuronio y d-tubocurarina: otra perspectiva / Precurarization with rocuronium and d-tubocurarine

Objetivo: Estudiar la precurarización de la succinilcolina utilizando d-tubocurarina y rocuronio introduciendo los métodos restrictivo, conceptos de velocidad de acción y recuperación y una nueva semiología para evaluar las fasciculaciones. Material y método: Se administraron succinilcolina (1 mg x Kg-1) (n =21) sola o precedida por rocuronio o d-tubocurarina (60 ó 50 ug x Kg-1) (n =21 c/u), determinándose: la fase inicial de comienzo hasta 80 por ciento de bloqueo, tiempo de comienzo, máximo efecto, duración clínica, tiempo de reversión espontánea entre 10 por ciento y 25 por ciento y 25 por ciento a 50 por ciento. Se calculó la velocidad de acción (inicial, final y global) como la relación tiempo/bloqueo fraccionado y la velocidad de recuperación. El método restrictivo fue empleado para el estudio del tiempo de comienzo, utilizando un rango restringido de bloqueo. Las fasciculaciones fueron evaluadas por su intensidad en seis regiones anatómicas por cuatro observadores imparciales e independientes y las medias de sus valoraciones utilizadas para analizarlas. Resultados: Aparentemente ambos desfasciculantes prolongan la fase inicial, tiempo de comienzo y velocidad de la succinilcolina, pero el método restrictivo únicamente lo confirmó para el tiempo de comienzo y la velocidad global. La velocidad inicial fue más rápida que la final. El rocuronio redujo el efecto y la duración clínica e incrementó la velocidad de recuperación de la succinilcolina. Las fasciculaciones fueron más frecuentes e intensas en el tronco y miembro superior izquierdo, pero los precurarizantes las redujeron tanto en intensidad como localización Discusión: La precurarización no modifica la fase inicial de comienzo, surgiendo la posibilidad de practicar una intubación temprana. Debido al acortamiento que provoca la precurarización con rocuronio se hace evidente la necesidad precoz de nuevas dosis de relajantes.

Objective: To study the precurarization of succinylcholine with d-tubocurarine and rocuronium, using the restrictive method, speed of action and recovery principles and a particular evaluation for fasciculations Material & Methods: Patients received succinylcholine (1 mg x Kg-1) (n =21) either alone or preceded by d-tubocurarine or rocuronium (60 ó 50 micron g x Kg-1) (n =21 e/a), and the following clinical measurements were made: earlyphase of onset time (up to 80 percent blockade), onset time, maximal block, clinical duration and recovery time between 10 percent and 25 percent and 25 percent to 50 percent. Speed of action (initial, final and global)as the ratio between time and fractional blockade and speed of recovery, were calculated. Restrictive method was used for the study of the entire onset time on patients included in a limited range of final block. Intensity of fasciculations was evaluated by four independent observers blind to the drugs used in six anatomical regions and their mean values used for analysis. Results: Apparently, precurarizing drugs prolonged initial phase, onset time and reduced speed for succinylcholine, but only onset time and global speed were confirmed by restrictive method. After rocuronium, maximal effect as well as clinical duration of succinylcholine werereduced and speed of recovery increased. Fasciculations were more frequent and intense at the trunk and left upper arm, but precurarization reduced both intensity and localization prevalence. Discussion: As lack of changes on the initial phase of onset time for succinylcholine inducedby precurarization was noticed, an early tracheal intubation could be contemplated. Due to reduction on clinical duration after rocuronium,new doses of muscle relaxants are sooner necessary. The present method for evaluation of fasciculations shows how far they are spread and how effective precurarization was, given rise to doubts on previous results.

Effects of neuromuscular blocking agents on central respiratory chemosensitivity in newborn rats

Neuromuscular blocking agents suppress central respiratory activity through their inhibitory effects on preinspiratory neurons and the synaptic drive from preinspiratory neurons to inspiratory neurons. Central CO2-chemosensitive areas, which partly consist of CO2-excited neurons, in the rostral ventrolateral medulla are thought to provide tonic drive to the central respiratory network and involve cholinergic mechanisms, which led us to hypothesize that neuromuscular blocking agents can inhibit CO2-excited neurons and attenuate respiratory CO2 responsiveness. To test this hypothesis, we used isolated brainstem-spinal cord preparations from newborn rats. The increase of C4 burst frequency induced by a hypercapnic superfusate, i.e. respiratory CO2 responsiveness, was suppressed by the application of neuromuscular blocking agents, either d-tubocurarine (10, 100M) or vecuronium (100M). These agents (40M) also induced hyperpolarization and decreases in firing frequency of CO2-excited neurons in the rostral ventrolateral medulla. Our results demonstrate that neuromuscular blocking agents inhibit CO2-excited tonic firing neurons and attenuate respiratory CO2 responsiveness.

Óxido Nítrico produzido durante a sepse intensifica a redução nos valores da razão de "train-of-four" (TOF) induzida por d-Tubocurarina e pancurônio / Produced Nitric oxide during sepse intensifies the reduction in the values of the reason of “train-of-four” (TOF) induced for d-Tubocurarine and pancuronium

Durante a sepse, grandes quantidades de óxido nítrico (NO) são sintetizadas pela enzima NO sintase tipo II. Em preparações neuromusculares, o NO produz ou acentua a fadiga de transmissão. 'Train-of-four'(TOF) são pulsos elétricos de 2 Hz aplicados ao nervo motor durante 2 segundos (4 contrações musculares) e o quociente entre as tensões musculares produzidas pela quarta (T4) e primeira (T1) contrações musculares (RTOF = T4/T1) é utilizado para avaliação do bloqueio da transmissão neuromuscular. A redução de RTOF é determinada por bloqueio dos receptores nicotínicos (Nn) facilitatórios e por estimulação dos receptores muscarínicos (M2) inibitórios do terminal nervoso motor. Estudos utilizando preparações neuromusculares de animais sépticos tratadas com bloqueadores neuromusculares em doses que reduzem os valores de RTOF sem promover alterações nas amplitudes das contrações musculares a 0,2 Hz não foram executados. Assim, utilizando preparações nervo ciático-músculo tibial anterior de ratos, verificamos que as menores doses de d-tubocurarina (d-TC), pancurônio (PANC) e galamina (GAL) capazes de produzir 30 por cento de redução em RTOF nos animais sham foram, respectivamente: 54,29 ± 2,86 mg/kg (n=7), 69,02 ± 6,13 mg/kg (n=5), 2,94 ± 0,33 mg/kg (n=4). A dose de d-TC foi menor em animais sépticos (34,53 ± 2,76 mg/kg, n=4), que em animais sham, porém os efeitos foram mais intensos e prolongados na sepse. d-TC (26,50 ± 0,68 mg/kg (n=5), promoveu 30 por cento de redução em RTOF nos animais sham submetidos à infusão de nitroprussiato de sódio (10 mg/kg/min). O tratamento com S-metilisotiouréia (SMT, 13 mg/kg) antagonizou a redução de RTOF em animais sépticos. As menores doses de PANC e GAL que reduziram RTOF em 30 por cento foram semelhantes em todos os grupos experimentais estudados e GAL promoveu efeitos similares em todas as condições experimentais. A redução de RTOF produzida por PANC foi menor que a induzida por d-TC e foi antagonizada pela administração de SMT....

Óxido Nítrico produzido durante a sepse intensifica a redução nos valores da razão de "train-of-four" (TOF) induzida por d-Tubocurarina e pancurônio / Produced Nitric oxide during sepse intensifies the reduction in the values of the reason of “train-of-four” (TOF) induced for d-Tubocurarine and pancuronium

Durante a sepse, grandes quantidades de óxido nítrico (NO) são sintetizadas pela enzima NO sintase tipo II. Em preparações neuromusculares, o NO produz ou acentua a fadiga de transmissão. 'Train-of-four'(TOF) são pulsos elétricos de 2 Hz aplicados ao nervo motor durante 2 segundos (4 contrações musculares) e o quociente entre as tensões musculares produzidas pela quarta (T4) e primeira (T1) contrações musculares (RTOF = T4/T1) é utilizado para avaliação do bloqueio da transmissão neuromuscular. A redução de RTOF é determinada por bloqueio dos receptores nicotínicos (Nn) facilitatórios e por estimulação dos receptores muscarínicos (M2) inibitórios do terminal nervoso motor. Estudos utilizando preparações neuromusculares de animais sépticos tratadas com bloqueadores neuromusculares em doses que reduzem os valores de RTOF sem promover alterações nas amplitudes das contrações musculares a 0,2 Hz não foram executados. Assim, utilizando preparações nervo ciático-músculo tibial anterior de ratos, verificamos que as menores doses de d-tubocurarina (d-TC), pancurônio (PANC) e galamina (GAL) capazes de produzir 30 por cento de redução em RTOF nos animais sham foram, respectivamente: 54,29 ± 2,86 mg/kg (n=7), 69,02 ± 6,13 mg/kg (n=5), 2,94 ± 0,33 mg/kg (n=4). A dose de d-TC foi menor em animais sépticos (34,53 ± 2,76 mg/kg, n=4), que em animais sham, porém os efeitos foram mais intensos e prolongados na sepse. d-TC (26,50 ± 0,68 mg/kg (n=5), promoveu 30 por cento de redução em RTOF nos animais sham submetidos à infusão de nitroprussiato de sódio (10 mg/kg/min). O tratamento com S-metilisotiouréia (SMT, 13 mg/kg) antagonizou a redução de RTOF em animais sépticos. As menores doses de PANC e GAL que reduziram RTOF em 30 por cento foram semelhantes em todos os grupos experimentais estudados e GAL promoveu efeitos similares em todas as condições experimentais. A redução de RTOF produzida por PANC foi menor que a induzida por d-TC e foi antagonizada pela administração de SMT....

The Neuromuscular Effects of Glucocorticoid Administration on the Skeletal Muscle of Rats / 대한마취과학회지

BACKGROUND: The administration of high doses of glucocorticoids can produce significant side effects including skeletal muscle atrophy, weakness and aberrant pharmacology. However, available reports have yielded conflicting results ranging from facilitatory to no change to inhibitory action of glucocoticoids on neuromuscular transmission. Also, the mechanisms for such changes are not known. Therefore, this study investigated the changes in muscle contractility and pharmacology after prednisolone administration in vivo. METHODS: With institutional approval, Sprague-Dawley rats were randomly allocated to 3 treatment groups, namely prednisolone (10 mg/kg daily for 7 days), saline control (equal volume of saline daily for 7 days) and an age-matched food-restriction group which grew at the same rate as the prednisolone group. On day 8 the rats were anesthetized, mechanically ventilated and the twitch response of the tibialis muscle to supramaximal stimulation of the sciatic nerve at 2 Hz for 2 sec every 12 sec, or at 50 or 100 Hz tetanus for 5 sec were monitored. The peak twitch and tetanic tensions were measured and tetanic fade was calculated. The cumulative dose-response curves of d-tubocurarine (d-TC) in the tibialis muscles were determined. The tibialis muscle weight relative to body weight was measured (muscle index), and the tension per unit muscle mass (i.e., specific tension) was calculated. The control and treatment groups were compared by a one way ANOVA test and P>0.05 was regarded as significant. RESULTS: Prednisolone caused a decline in growth rate and the ED50 of dTC relative to saline. Food-restriction caused a decline in growth rate and an increase in muscle index relative to saline, and a decline in tension relative to prednisolone. CONCLUSIONS: These results indicate that prednisolone can alter the sensitivity of skeletal muscles to dTC even without or before changes in neuromuscular contractility become apparent. Therefore, titration of doses of nondepolarizing neuromuscular blocking agents may be indicated in patients receiving glucocorticoid therapy.

Pharmacological evaluation of muscle relaxant potency of mivacurium chloride against standard non-depolarizing muscle relaxant D. tubocurarin

The study was designed to evaluate potency of neuromuscular blocking activity of mivacurium chloride on the preparation of isolated frog's rectus abdominis muscle in contrast to that of the standard non - depolarizing muscle relaxant d- tubocurarin. The contractile response of the muscle was recorded in response to Acetylcholine [0.1 microg / ml] followed by addition of mivacurium to the bath Fluid and d- tubocurarin in a logarithmic increasing doses [1 mic/ ml- 16 mic/ml]. The percentage of inhibition by d-tubocurarin was more marked than that of mivacurium

Inhibitory Effects of Structurally Different Neuromuscular Blockers on the Serotonin Type 3 Receptor Expressed in Xenopus Oocytes / 대한마취과학회지

BACKGROUND: The serotonin type 3 receptors are diffusely distributed in both the central and the peripheral nervous system. Physiological and pathophysiological processes thought to be mediated by this receptor include nausea and vomiting, peripheral nociception and central antinociception, conditioned aversion response to drugs, anxiety, and cognition. Because of the structural similarity between the nicotinic acetylcholine receptor and the 5HT3 receptor, we investigated the effects of clinically used neuromuscular blockers on the 5HT3 receptor function related with PONV. METHODS: A cDNA clone encoding the full length murine 5HT3a receptor was subcloned into an oocyte expression vector and 50 ng of cRNA transcribed in vitro injected per oocyte. After 24 72 h incubation, oocytes were placed into a recording chamber continuously perfused with frog Ringer's solution and electrophysiological recordings were obtained by the two electrode voltage clamp technique. Serotonin with or without the various drugs were bath applied by a computer controlled solenoid valve. Peak currents induced by the drug applications were measured and dose responses were obtained. RESULTS: The 5HT3 receptor expression in Xenopus oocyte was identified by the pharmacologic tools. Serotonin induced rapid inward currents, and thus was showed dose-dependent: KD = 2.5 micrometer, Hill coefficiency = 2.09. Inhibition by the neuromuscular blockers showed dose-dependence and their inhibitory potency on 5HT3 receptor (IC50) was in order of d-tubocurarine (0.046 micrometer) > vecuronium (16.32 micrometer) > gallamine (1,169 micrometer). CONCLUSIONS: There was a different inhibitory effect of nicotinic cholinergic antagonists, clinically used neuromuscular blockers, on the 5HT3 receptor and a judicious selection of them might contribute to reducing the incidence of PONV clinically.

Inhibitory Effects of Structurally Different Neuromuscular Blockers on the Serotonin Type 3 Receptor Expressed in Xenopus Oocytes / 대한마취과학회지

BACKGROUND: The serotonin type 3 receptors are diffusely distributed in both the central and the peripheral nervous system. Physiological and pathophysiological processes thought to be mediated by this receptor include nausea and vomiting, peripheral nociception and central antinociception, conditioned aversion response to drugs, anxiety, and cognition. Because of the structural similarity between the nicotinic acetylcholine receptor and the 5HT3 receptor, we investigated the effects of clinically used neuromuscular blockers on the 5HT3 receptor function related with PONV. METHODS: A cDNA clone encoding the full length murine 5HT3a receptor was subcloned into an oocyte expression vector and 50 ng of cRNA transcribed in vitro injected per oocyte. After 24 72 h incubation, oocytes were placed into a recording chamber continuously perfused with frog Ringer's solution and electrophysiological recordings were obtained by the two electrode voltage clamp technique. Serotonin with or without the various drugs were bath applied by a computer controlled solenoid valve. Peak currents induced by the drug applications were measured and dose responses were obtained. RESULTS: The 5HT3 receptor expression in Xenopus oocyte was identified by the pharmacologic tools. Serotonin induced rapid inward currents, and thus was showed dose-dependent: KD = 2.5 micrometer, Hill coefficiency = 2.09. Inhibition by the neuromuscular blockers showed dose-dependence and their inhibitory potency on 5HT3 receptor (IC50) was in order of d-tubocurarine (0.046 micrometer) > vecuronium (16.32 micrometer) > gallamine (1,169 micrometer). CONCLUSIONS: There was a different inhibitory effect of nicotinic cholinergic antagonists, clinically used neuromuscular blockers, on the 5HT3 receptor and a judicious selection of them might contribute to reducing the incidence of PONV clinically.

Tetanic fade induced by d-Tubocurarine, Hexamethonium and Neostigmine in phrenic nerve diaphragm rats

A acetilcolina liberada do terminal nervoso motor (TNM) pode modular sua pr6pria liberagdo (automodulação do TNM), interagindo com receptores nicotinicos (autoestimulação do TNM) ou muscarinicos (autoinibição do TNM) pré-juncionais. Por outro lado, tem-se demonstrado que a neuropatia induzida pelo estado diabético determine vários danos estruturais no interior do TNM, sem, contudo, interferir na velocidade e na integridade da transmissão neuromuscular. Estudos farmacológicos demonstram que animais diabéticos, quando comparados aos normais, são menos sensíveis a alguns bloqueadores neuromusculares (d-tubocurarina, galamina, pancurônio e decametônio). Esses resultados sugerem que alguma modificação no sistema de automodulação do TNM pode contrabalançar as deficiências neuronais induzidas pelo estado diabético. Dessa forma, o presente estudo foi conduzido com preparações nervo frênico-diafragma isolado de ratos (obtidas de animais normais e diabéticos) na tentativa de verificar se existiriam diferenças na fadiga neuromuscular induzida por drogas (d-tubocurarina, neostigmina, hexametônio). Nossos resultados mostraram que, embora não existissem diferenças na indução da fadiga neuromuscular induzida por d-tubocurarina, neostigmina ou hexametônio, o recobro da fadiga neuromuscular induzida por d-tubocurarina foi mais rápido em preparações neuromusculares obtidas de animais diabéticos. Essa diferença pode estar relacionada a alguma modificação induzida pelo estado diabético que determinou redugio da afinidade da d-tubocurarina para os receptores nicotínicos pré-juncionais

The Effect of Frequency of Stimulation on Partial Twitch Depression in a Rat Phrenic Nerve Hemidiaphragm Preparation / 대한마취과학회지

Background: This study was designed to determine whether presynaptic receptor blockade could be differentiated from postsynaptic receptor blockade by examining the effect of increasing frequencies of indirect stimulation on partial twitch depression in vitro rat phrenic nerve hemidiaphragm preparations. Methods: After isolating rat phrenic nerve hemidiaphragm preparation, T200/T1 ratio (twitch height of the 200th stimuli divided by that of the 1st stimuli) at frequencies of 0.2, 0.5, 1.0, and 2.0 Hz using a drug concentration which provided approximately 20% twitch depression at 0.1 Hz was calculated. To compare T200/T1 ratios with TOF ratios, 2.0 Hz TOF response was measured immediately after 200th stimuli at either frequency of stimulation. Results: Hexamethonium caused a marked decrease in T200/T1 ratio at 0.5~2.0 Hz of stimulation, whereas alpha-bungarotoxin caused no change in T200/T1 ratios at up to 2.0 Hz of stimulation. The T200/T1 ratios produced by d-tubocurarine, vecuronium, mivacurium, and rocuronium located intermediate between alpha-bungarotoxin and hexamethonium, however significant differences among four drugs were found at 2.0 Hz. The propensity for decrease in T200/T1 ratios at 2.0 Hz might differ from this study: hexamethonium >d-tubocurarine >rocuronium >mivacurium = vecuronium >alpha-bungarotoxin. T200/T1 ratios at 2.0 Hz were not different from TOF ratios. Conclusions: When the observed effects in this study were provided with result of alpha-bungarotoxin acting predominantly at postsynaptic receptors and hexamethonium acting predominantly at presynaptic receptors, the effects of nondepolarizing muscle relaxants at each binding site could be differentiated by examining the T200/T1 ratios at 2.0 Hz.

Influence of Decamethonium on the Neuromuscular Blocking Action of d-Tubocurarine in the Rat Phrenic Nerve Hemidiaphragm Preparation / 대한마취과학회지

BACKGROUND: To elucidate the mechanism of interaction between depolarizing and nondepolarizing muscle relaxants, train-of-four (TOF) fade during onset of neuromuscular blockade of d-tubocurarine (dTC) with or without decamethonium (C10) was evaluated in a rat phrenic nerve hemidiaphragm preparation. METHODS: Phrenic nerve hemidiaphragm preparations from 250~300 g Sprague Dawley rats (n=20) were suspended in a Krebs solution bubbled with 5% CO2 in O2 at 32oC. Phrenic nerves were stimulated with supramaximal stimuli of 0.2 ms duration at 0.15 Hz single twitch and 2 Hz TOF by a Grass S88 stimulator and the contractions of the hemidiaphragm were detected by a Grass FT03 force transducer then recorded. Estimation of ED50 for the dose response data were performed by a linear regression. The statistical significance of the results was determined by Wilcoxon Rank Sum test. p<0.05 was considered significant. RESULTS: Mean ED50 values of dTC and C10 calculated from the dose response relations were 7.76 microgram/ml and 0.65 microgram/ml respectively. Compared to adminstration of 2xED50 of dTC alone, TOF ratios at 75% and 50% of twitch height were markedly decreased by combination of ED50 of C10 and ED50 of dTC with statistic significance (67 +/- 1.9% vs. 46 +/- 3.1% and 36 +/- 2.5% vs. 7 +/- 2.5%). Conclusion: If fade in response to TOF stimulation represents a prejunctional effect, the results from this study suggests that the presynaptic action of C10 has some role in the mechanism of the interaction between dTC and C10 in the rat.

Dual action of d-tubocurarine on large-conductance Ca2+-activated K+ channels from rat brain reconstituted into planar lipid bilayer

Using the planar lipid bilayer method, we investigated the effect of d-tubocurarine (dTC) on the extracellular side of large-conductance Ca2+-activated K+ channel from rat brain. When the initial open probability (Po) of the channel was relatively high, dTC decreased channel activity in a concentration dependent manner. In contrast, when the initial Po was lower, sub-micro molar dTC increased channel activity by destabilizing the closed states of the channel. Further addition of dTC up to micro molar range decreased channel activity. This dual effect of dTC implicates that there exist at least two different binding sites for dTC.

The characterization of the increase of membrane conductance after depolarization in single rat adrenal chromaffin cells

The conductance change evoked by step depolarization was studied in primarily cultured rat adrenal chromaffin cells using patch-clamp and capacitance measurement techniques. When we applied a depolarizing pulse to a chromaffin cell, the inward calcium current was followed by an outward current and depolarization-induced exocytosis was accompanied by an increase in conductance trace. The slow inward tail current which has the same time course as the conductance change was observed in current recording. The activation of slow tail current was calcium-dependent. Reversal potentials agreed with Nernst equation assuming relative permeability of Cs+ to K+ is 0.095. The outward current and tail current were blocked by apamin (200 nM) and d-tubocurarine (2 mM). The conductance change was blocked by apamin and did not affect membrane capacitance recording. We confirmed that conductance change after depolarization comes from the activation of the SK channel and can be blocked by application of the SK channel blockers. Consequently, it is necessary to consider blocking of the SK channel during membrane capacitance recording.

Right Cognition of Succinylcholine / 대한마취과학회지

Non-depolarizing muscle relaxant; d-tubocurarine was introduced clinically in 1942. Thereafter depolarizing muscle relaxant; succinylcholine was introduced in 1951. Those muscle relaxants were highly contributed in modern anesthesia practice today. But, since many years ago complications of succinylcholine were reported clearly so many anesthesia practice. Complications were such as ventricular arrythmia(cardiac arrest), fasciculation, hyperkalemia, muscle pain, elevation of intragastric, intraocular & intracranial pressure, prolonged apnea, generalized muscle clonus, masseter muscle rigidity and malignant hyperthermia etc. Succinylcholine was still used in clinical practice despite of many complications reported as long as more than 45 years. Finally, FDA(USA) decleared the routine use of succinylcholine was contraindicated in children and adolescents. Many textbooks of anesthesiology shows that use of succinylcholine was contraindicated in children and adolescents those were published recently since 1994. What is the current status of succinylcholine in despite of changing current concept of succinylcholine use in Korea? Succinylcholine is still inadvertently used in Korea over 79% of resident training hospital. Intravenous dantrolene reserve was only one hospital(1.4%). Undoubtedly, amazing things were going on in Korea. Seventeen cases of malignant hyperthermia had been reported from 1971 to 1996 on Korean medical journals. It's mortality was 70.6%. Not only the reported malignant hyperthermia, there are many cardiac arrest during anesthesia reported on Korean medical journals. Etiological analysis of cardiac arrest was reviewed some of them, there are certain numbers of cardiac arrest cases confirmed by succinylcholine was guilty. What is the counterplan? Change the current concept of succinylcholine is important. Conclusions ; 1. Non-depolarizing mucle relaxant should be used for intubation &/or muscle relaxation. 2. Hot line for malignant hyperthermia should be established.. 3. Intravenous dantrolene reserve is necessary. 4. Routine monitoring during anesthesia should be blood pressure, ECG, SPO2, ETCO2, body temperature and peripheral nerve stimulator.

Attenuation of the agonistic effects of succinylcholine on the nicotinic receptors by the pretreatment with d-tubocurarine and tracrium

The present study was designed to evaluate the effects of pretreatment with d-tubocurarine and tracrium on succinylcholine induced increases in plasma catecholamines concentration, plasma K+ level, mean blood pressure, heart rate and fasciculation in patients anesthetized with halothane. Eighteen patients were randomly divided into three groups: Saline, d-tubocurarine and tracrium groups. The mean plasma catecholamines concentration, mean plasma K+ level, mean blood pressure and mean heart rate were significantly increase in the saline group after 4 and 10 minutes from i.v. succinylcholine injection. Also, the fasciculation was peaked. In d-tubocurarine group, there were no significant changes in the above measurements. In tracrium group, there were significant increases in catecholamines and K+ levels. D-tubocurarine attenuated the cardiovascular effects and the induced increases in plasma catecholamines and K+ levels following succinylcholine injection. Tracrium attenuated the cardiovascular effects, but to a lesser extent and did not attenuate the increases in plasma catecholamines following succinylcholine injection. The results obtained in the present study showed that the nicotinic receptors on the sympathetic ganglia are not the only sites of interaction, suggest the possibility that the presynaptic nicotinic receptors on the postganglionic sympathetic terminals might be involved in the interaction between these drugs

Comparison of d-tubocurarine with vecuronium as the priming drug for vecuronium induced neuromuscular blockade / 대한마취과학회지

Administration of a subparalytic dose of a nondepolarizing muscle relaxant prior to intubating dose hastens the onset time of neuromuscular blockade. This study was designed to investigate the influence of a priming dose of vecuronium (0.015 mg/kg) and d-tubocurarine (0.05 mg/kg) on intubating dose of vecuronium (0.085 mg/kg). The authors measured TOF ratio using neuromuscular monitoring. This monitoring was carried out by stimulation of ulnar nerve at a frequency of 2Hz every 20 seconds using Datex relaxograph to measure the compound evoked electrographic response of hypothenar muscle. The patients were randomly divided into two groups as priming dose ; vecuronium and dtubocurarine (DTC) group respectively. Mixture of two different nondepolarizing muscle relaxant may produce synergism, although the reason for this synergism is unknown. It may be the results of the action of the drugs at different sites. In our study, we found the results as follows ;1) The rapid onset was occured with d-tubocurarine(0.05 mg/kg) as priming drug than vecuronium (0.015 mg/kg) 2) The duration was longer when d-tubocurarine was used (P<0.05) The authors conclude that the onset is more rapid and the duration is longer when other species of nondepolarizing muscle relaxant is used than same agent is used as priming drug.

The Effect of Small Dose of Nondepolarizing Muscle Relaxant Administered Prior to Succinylcholine on Intubating Condition / 대한마취과학회지

Subparalyzing dose of nodepolarizing relaxants prior to injection of succinylcholine has been used to prevent various adverse effects induced after succinylcholine. For investigating interactions between succinylcholine and small doses of four non-depolar-izing agents, the 112 subjects that were ASA class 1-2 and no existing neuromuscular conduction system disorder were divided into 5 groups that were control group(only succinylcholine 1 mg/kg) and pretreated group d-tubocurarine 0.5 mg/kg, atracurium 0.08 mg/kg, vecuronium 0.01 mg/kg and pancuronium 0.01 mg/kg. In each group, the plasma concentration of K+ and PChE before and after use of succinylcholine, fasciculation, onset and recovery time of succinylcholine block and intubating conditon were observed. The results are as follows; In the pretreated group, there were no significant changes of plasma concentration of K+ and plasma cholinesterase(Table 3) but diminished the incidence of fascieulation, delayed the onset time and shorted the recovery time of succinylcholine block(Table 4), and worse in intubating condition(Table 5) except pancuronium treated group. It was concluded that these seem to make worse condition of intubation, while small doses of nondepolarizing muscle relaxants except pancuronium antagonize depolarizing muscle relaxant.