OBJECTIVETo determine the effect of neostigmine on antagonizing atracurium-induced neuromuscular blockage with sulfate magnesium pretreatment.

METHODSForty patients who undertook elective gynecologic laparoscopic examinations and treatments under general anesthesia were randomized into four groups (group A, B, C, and D, group A paired with group C, and group B paired with group D). Before induction of general anesthesia, patients in group A and group C received MgSO4 30 mg/kg in saline intravenously within 5 min, while patients in group B and group D received the same volume of saline. Anesthesia was induced with fentanyl and propofol; subsequently tracheal intubation was performed with 0.5 mg/kg atracurium after stabilization of the electromyography recording, and neostigmine (0.02 mg/kg) and atropine (0.01 mg/kg) were infused in group C and group D when neuromuscular recovery (T1/T(C)) reached 10%. T1/T(C) changes after neostigmine infusion as well as haemodynamic changes and other responses during induction and neostigmine and atropine infusion were recorded.

RESULTSThe neuromuscular recovery speed had no significant difference between group A and group B after the neuromuscular recovery reached 10%, but it was lower in group C than in group D (P < 0.05). Significant difference existed between group AC and group BD (P < 0.05). No haemodynamic changes and other responses were found during induction and neostigmine and atropine infusion.

CONCLUSIONNeostigmine-induced neuromuscular recovery can be attenuated in patients pretreated with magnesium sulfate.

Adolescent ; Adult ; Anesthesia, General ; Atracurium ; antagonists & inhibitors ; Cholinesterase Inhibitors ; pharmacology ; Female ; Humans ; Laparoscopy ; Magnesium Sulfate ; pharmacology ; Middle Aged ; Neostigmine ; pharmacology ; Neuromuscular Blockade ; Neuromuscular Nondepolarizing Agents ; antagonists & inhibitors

In this study, we tested the hypothesis that volatile anesthetic enhancement of muscle relaxation is the result of combined drug effects on the nicotinic acetylcholine receptors. The poly A m RNA from muscle by isolation were microinjected into Xenopus oocytes for receptor expression. Concentration-effect curves for the inhibition of Ach-induced currents were established for vecuronium, rocuranium, and isoflurane. Subsequently, inhibitory effects of NDMRs were studied in the presence of the isoflurane at a concentration equivalent to half the concentration producing a 50% inhibition alone. All tested drugs produced rapid and readily reversible concentration-dependent inhibition. The 50% inhibitory concentration values were 889 micromol/L (95% CI: 711-1214 micromol). 33.4 micromol (95% CI: 27.1-41.7 nmol) and 9.2 nmol (95% CI: 7.9-12.3 nmol) for isoflurane. rocuranium and vecuronium, respectively. Coapplication of isoflurane significantly enhanced the inhibitory effects of rocuranium and vecuronium, and it was especially so at low concentration of NMDRs. Isoflurane increases the potency of NDMRs, possibly by enhancing antagonist affinity at the receptor site.
Androstanols ; pharmacology ; Anesthetics, Inhalation ; pharmacology ; Animals ; Drug Synergism ; Female ; Isoflurane ; pharmacology ; Neuromuscular Blocking Agents ; pharmacology ; Neuromuscular Junction ; drug effects ; Neuromuscular Nondepolarizing Agents ; pharmacology ; Oocytes ; Receptors, Nicotinic ; drug effects ; Vecuronium Bromide ; pharmacology ; Xenopus laevis

In this study, we tested the hypothesis that volatile anesthetic enhancement of muscle relaxation is the result of combined drug effects on the nicotinic acetylcholine receptors. The poly A m RNA from muscle by isolation were microinjected into Xenopus oocytes for receptor expression. Concentration-effect curves for the inhibition of Ach-induced currents were established for vecuronium, rocuranium, and isoflurane. Subsequently, inhibitory effects of NDMRs were studied in the presence of the isoflurane at a concentration equivalent to half the concentration producing a 50% inhibition alone. All tested drugs produced rapid and readily reversible concentration-dependent inhibition. The 50% inhibitory concentration values were 889 micromol/L (95% CI: 711-1214 micromol). 33.4 micromol (95% CI: 27.1-41.7 nmol) and 9.2 nmol (95% CI: 7.9-12.3 nmol) for isoflurane. rocuranium and vecuronium, respectively. Coapplication of isoflurane significantly enhanced the inhibitory effects of rocuranium and vecuronium, and it was especially so at low concentration of NMDRs. Isoflurane increases the potency of NDMRs, possibly by enhancing antagonist affinity at the receptor site.
Androstanols/*pharmacology ; Anesthetics, Inhalation/pharmacology ; Drug Synergism ; Isoflurane/*pharmacology ; Neuromuscular Blocking Agents/*pharmacology ; Neuromuscular Junction/drug effects ; Neuromuscular Nondepolarizing Agents/*pharmacology ; Oocytes ; Receptors, Nicotinic/*drug effects ; Vecuronium Bromide/pharmacology ; Xenopus laevis

OBJECTIVETo determine the effects of atracurium pretreatment with magnesium on speed of onset, duration, and recovery of neuromuscular block.

METHODSThirty patients who were undergoing elective gynecologic laparoscopic examination and treatments under general anesthesia were randomized into magnesium group (n = 15) and control group (n = 15). Before induction of general anesthesia, patients in magnesium group intravenously received MgSO4 30 mg/kg in saline within 5 minutes, and patients in control group received the same volume of saline without MgSO4. In both groups, the train-of-four (TOF) responses to stimuli of the ulnar nerve were measured at intervals of 12 seconds. Anesthesia was induced with Fentanyl and Propofol through target controlled infusion (TCI), and tracheal intubation was performed with 0.5 mg/kg atracurium after stabilization of the electromyography recording. The onset time of muscle relaxation, clinical duration of action, recovery index, and recovery time were recorded. To determine serum magnesium and calcium levels, blood samples were collected before MgSO4/saline infusion and at the end of operation. Haemodynamic changes and other responses during induction were also recorded.

RESULTSThe onset time from the end of injection to maximum neuromuscular blockade was significantly shorter in magnesium group than in control group (P < 0.01). Duration of relaxant action, recovery index, and recovery time in magnesium group were significantly prolonged than in control group (P < 0.01). Serum magnesium level significantly decreased after management (P < 0.01), and there was also a decrease trend in magnesium group. No change of serum calcium levels in both groups was observed. No adverse event was reported.

CONCLUSIONPrior administration of magnesium sulphate can increase the onset speed of atracurium and prolong the duration of atracurium-induced neuromuscular blockade.

Adolescent ; Adult ; Anesthesia Recovery Period ; Anesthesia, General ; Atracurium ; pharmacology ; Drug Synergism ; Female ; Humans ; Magnesium Sulfate ; pharmacology ; Middle Aged ; Neuromuscular Blockade ; Neuromuscular Junction ; drug effects ; Neuromuscular Nondepolarizing Agents ; pharmacology ; Time Factors ; Young Adult

Objective To investigate diabetes-mediated changes in the neuromuscular pharmacodynamics of rocuronium in rats. Methods Diabetes mellitus was induced by a single injection of streptozotocin in rats.A total of 24 male SD rats were assigned to four groups using random number table:the normal control group,diabetic 2-week group,diabetic 4-week group,and diabetic 8-week group(6 rats per group).The sciatic nerve was stimulated in a rain-of-four(TOF)pattern,and the twitch tension changes in the tibialis anterior muscle were demonstrated by mechanomyography after intravenous injection of rocuronium in vivo.The time course characteristics of rocuronium,including onset time,and the recovery time from rocuronium injection to TOF ratio 75%(RT75%)and 90%(RT90%),were recorded,and half maximal inhibitory concentration(IC)values of rocuronium were determined using a four-parameter dose response curve. Results Compared with the normal controls,the diabetic rats had significantly prolonged onset time of rocuronium,while the RT75% and RT90% were decreased at all rocuronium doses(P<0.001).The time course changes became increasingly significant as the duration of diabetes lengthened(P<0.001).The IC and 95% confidence interval values for rocuronium in the normal control group,diabetic 2-week group,diabetic 4-week group,and diabetic 8-week group were 0.37(0.35-0.38)mg/kg,0.44(0.43-0.46)mg/kg,0.59(0.57-0.61)mg/kg,and 0.64(0.61-0.66)mg/kg,respectively.IC values were significantly higher in the diabetic groups vs.normal control(P<0.001)and gradually increased as the duration of diabetes lengthened(P<0.001).Conclusion Diabetes is associated with the rat skeletal muscle hyposensitivity to rocuronium,which is featured by prolonged onset time of rocuronium,decreased RT 75% and RT 90%,and right shift of the cumulative dose-response curve of rocuronium.
Animals ; Diabetes Mellitus, Experimental ; physiopathology ; Male ; Muscle, Skeletal ; drug effects ; Neuromuscular Nondepolarizing Agents ; pharmacology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Rocuronium ; pharmacology

BACKGROUNDThe antagonistic actions of anticholinesterase drugs on non-depolarizing muscle relaxants are theoretically related to the activity of acetylcholinesterase (AChE) in the neuromuscular junction (NMJ). However, till date the changes of AChE activity in the NMJ during sepsis have not been directly investigated. We aimed to investigate the effects of sepsis on the antagonistic actions of neostigmine on rocuronium (Roc) and the underlying changes of AChE activity in the NMJ in a rat model of cecal ligation and puncture (CLP).

METHODSA total of 28 male adult Sprague-Dawley rats were randomized to undergo a sham surgery (the sham group, n = 12) or CLP (the septic group, n = 16). After 24 h, the time-response curves of the antagonistic actions of 0.1 or 0.5 μmol/L of neostigmine on Roc (10 μmol/L)-depressed diaphragm twitch tension were measured. Meanwhile, the activity of AChE in the NMJ was detected using a modified Karnovsky and Roots method. The mRNA levels of the primary transcript and the type T transcript of AChE (AChET) in the diaphragm were determined by real-time reverse transcription-polymerase chain reaction.

RESULTSFour of 16 rats in the septic group died within 24 h. The time-response curves of both two concentrations of neostigmine in the septic group showed significant upward shifts from those in the sham group (P < 0.001 for 0.1 μmol/L; P = 0.009 for 0.5 μmol/L). Meanwhile, the average optical density of AChE in the NMJ in the septic group was significantly lower than that in the sham group (0.517 ± 0.045 vs. 1.047 ± 0.087, P < 0.001). The AChE and AChETmRNA expression levels in the septic group were significantly lower than those in the sham group (P = 0.002 for AChE; P = 0.001 for AChET).

CONCLUSIONSSepsis strengthened the antagonistic actions of neostigmine on Roc-depressed twitch tension of the diaphragm by inhibiting the activity of AChE in the NMJ. The reduced content of AChE might be one of the possible causes of the decreased AChE activity in the NMJ.

Acetylcholinesterase ; metabolism ; Androstanols ; pharmacology ; Animals ; Cecum ; injuries ; Cholinesterase Inhibitors ; pharmacology ; Diaphragm ; drug effects ; metabolism ; Disease Models, Animal ; Ligation ; Male ; Neostigmine ; pharmacology ; Neuromuscular Junction ; enzymology ; Neuromuscular Nondepolarizing Agents ; pharmacology ; Punctures ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Sepsis ; physiopathology

The neuromuscular and hem+odynamic effects of mivacurium 0.15 mg/kg and succinylcholine 1 mg/kg were compared in 26 adult patients (ASA I and II) during nitrous oxide-oxygen-propofol-fentanyl anesthesia. Neuromuscular block was monitored by recording the compound electromyogram of the hypothenar muscle resulting from supramaximal train-of-four stimuli applied to the ulnar nerve. Time to onset of over 95% block and duration to 25% recovery of control twitch after injection of mivacurium were significantly longer than for succinylcholine (201 +/- 37.6 vs 54 +/- 5.2 sec and 13.0 +/- 2.2 vs 8.4 +/- 2.1 min; mean +/- SD). Onset of mivacurium with priming technique was shortened (125 +/- 20.7 sec), but was also slower than that of succinylcholine. Although the recovery index during spontaneous recovery was significantly longer for mivacurium than for succinylcholine (6.9 +/- 1.3 vs 5.1 +/- 0.9 min), antagonism with neostigmine at 25% recovery of twitch height sufficiently facilitated the recovery index of mivacurium (4.5 +/- 1.0 min) to a level similar to that of succinylcholine with no statistical difference. The hemodynamic effects of mivacurium were few as compared to those of succinylcholine. In conclusion, mivacurium is considered to have additional advantages for short procedures when succinylcholine is undesirable.
Adult ; Anesthesia ; Female ; Fentanyl/administration & dosage ; Hemodynamics/*drug effects ; Humans ; Isoquinolines/*pharmacology ; Male ; Neuromuscular Junction/*drug effects ; Neuromuscular Nondepolarizing Agents/*pharmacology ; Nitrous Oxide/administration & dosage ; Propofol/administration & dosage ; Succinylcholine/*pharmacology

AIMTo investigate the roles of acetylcholine (ACh) receptors in the rapid effects of corticosterone (CORT) on the presympathetic neurons in the rostral ventrolateral medulla (RVLM) of rats, and study the non-genomic mechanism of glucocorticoid (GC) in the integration of sympathetic cardiovascular activity.

METHODSThe effects of microelectrophoresis of CORT on the discharge of the presympathetic neurons in the RVLM were observed by extracellular recording in urethane-anaesthetized rats. The responses of atropine (a blocker for M type of ACh receptor, ATR), d-tubocurarine (a blocker for N1 type of ACh receptor, d-TC) and hexamethonium (a blocker for N2 type of ACh receptor, C6) to the effects of CORT on the presympathetic neurons were investigated respectively.

RESULTSTotally 33 presympathetic neurons in the RVLM were recorded. Among them the firing rate of 25 (76%) presympathetic neurons was increased by microelectrophoresis of CORT. The effects of CORT were also positively correlated with the currents. In the other 8 presympathetic neurons, had was shown no effect after microelectrophoresis of CORT. In 10 presympathetic neurons, which discharge was increased by CORT, microelectrophoresis of ATR decreased the firing rate of these presympathetic neurons (P < 0.05), and did not fully block the excitatory effect induced by CORT. In both 7 and 6 presympathetic neurons, application of d-TC and C6 had no effect on these neurons respectively, and did not fully block the excitatory effect induced by CORT.

CONCLUSIONCORT had rapid excitatory effects on the presympathetic neurons in the RVLM, which effect might be independent on ACh receptors.

Animals ; Cholinergic Antagonists ; pharmacology ; Corticosterone ; pharmacology ; Electrophoresis, Microchip ; Male ; Medulla Oblongata ; drug effects ; physiology ; Neuromuscular Nondepolarizing Agents ; pharmacology ; Neurons ; drug effects ; physiology ; Nicotinic Antagonists ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptors, Cholinergic ; physiology

OBJECTIVETo evaluate the effect of dexmedetomidine (Dex) on bispectral index (BIS) and auditory evoked potential index (AAI) during anesthesia with target controlled infusion (TCI) of propofol and remifentanyl.

METHODSThirty adult patients (ASA I approximate, equalsII) who were scheduled for elective thyroidectomy were monitored with BIS, AAI, ECG, blood pressure, end-tidal CO(2), and pulse oximeter before and during anesthesia. Anesthesia was induced by TCI with propofol 4 mg/L and remifentanyl 1 mu g/kg. After loss of consciousness the patients were intubated after rocuronium 0.6 mg/kg intravenous injection, remifentanyl was then infused at 0.2 microg/(kg x min)(-1) and propofol infusion (Ct) was titrated to maintain a BIS value at 50 +/- 3. At 10 min after stabilization of anesthesia the patients were randomly and double-blindly divided into 2 groups: Group D (n=15) received Dex 0.4 mu g/kg iv administered over 5 min and Group C (n=15) received equal volume of normal saline. Values of BIS, AAI, MAP, HR were recorded every 2 min within 20 min after the administration of the drugs.

RESULTSBefore anesthesia the BIS index was 90 +/- 2 in Group D and 92 +/- 2 in Group C, AAI was 81 +/- 1 in Group D and 78 +/- 1 in Group C. In anesthesia with target controlled infusion of propofol, BIS index showed a significant decrease with the i.v. administration of Dex 0.4 microg/kg, while AAI remained unchanged. In Group C, both of BIS and AAI remained unchanged after saline injection.

CONCLUSIONDuring propofol and remifentanyl anesthesia, after the administration of Dex, BIS value demonstrates a predominant decrease, whereas AAI shows no changes.

Adrenergic alpha-Agonists ; administration & dosage ; Adult ; Androstanols ; administration & dosage ; Anesthetics, Combined ; administration & dosage ; Anesthetics, Intravenous ; administration & dosage ; Dexmedetomidine ; administration & dosage ; pharmacology ; Double-Blind Method ; Evoked Potentials, Auditory ; drug effects ; Female ; Humans ; Infusions, Intravenous ; methods ; Male ; Medetomidine ; pharmacology ; Middle Aged ; Monitoring, Intraoperative ; methods ; Neuromuscular Nondepolarizing Agents ; administration & dosage ; Piperidines ; administration & dosage ; pharmacology ; Propofol ; administration & dosage ; pharmacology ; Thyroidectomy

The purpose of this study was to determine the effectiveness of antihistamine therapy for withdrawal movements caused by rocuronium injection. One hundred seventy one ASA I-II adults undergoing elective surgery were randomly assigned to one of two groups. Patients in the control group (Group C) were premedicated with 2 mL normal saline, and those in the antihistamine group (Group A) were pre-medicated with 2 mL (45.5 mg) pheniramine maleate. After the administration of thiopental sodium 5 mg/kg, rocuronium 0.6 mg/kg was injected. Withdrawal movements were assessed using a four-grade scale. The administration of antihistamine reveals lower grade of withdrawal movement after rocuronium injection.
Adult ; Androstanols/*administration & dosage/adverse effects ; Anesthetics, Intravenous/administration & dosage ; Double-Blind Method ; Female ; Histamine H1 Antagonists/*pharmacology ; Humans ; Incidence ; Injections, Intravenous ; Male ; Middle Aged ; Movement/drug effects/physiology ; Neuromuscular Nondepolarizing Agents/*administration & dosage/adverse effects ; Pain/chemically induced ; Pain Measurement ; Pheniramine/*pharmacology ; Thiopental/administration & dosage