scholarly journals The influence of lidocaine and racemic bupivacaine on neuromuscular blockade produced by rocuronium: a study in rat phrenic nerve-diaphragm preparation

2009 ◽  
Vol 24 (3) ◽  
pp. 211-215 ◽  
Author(s):  
Vanessa Henriques Carvalho ◽  
Angélica de Fátima de Assunção Braga ◽  
Franklin Sarmento da Silva Braga ◽  
Yolanda Christina S. Loyola ◽  
Daniele Ribeiro de Araújo ◽  
...  
Keyword(s):  
Neuromuscular Blockade ◽  
Phrenic Nerve ◽  
Local Anesthetics ◽  
Neuromuscular Transmission ◽  
Membrane Potentials ◽  
Diaphragm Muscle ◽  
Muscle Response ◽  
End Plate ◽  
Indirect Stimulation

PURPOSE: To evaluate in vitro lidocaine and racemic bupivacaine effects in neuromuscular transmission and in neuromuscular blockade produced by rocuronium. METHODS: Rats were distributed in 5 groups (n = 5) in agreement with the studied drugs: lidocaine, racemic bupivacaine, rocuronium, separately (Groups I, II, III); rocuronium in preparations exposed to local anesthetics (Groups IV, V). The concentrations used were: 20 µg/mL, 5 µg/mL and 4 µg/mL, for lidocaine, bupivacaine and rocuronium, respectively. It was evaluated: 1) amplitude of diaphragm muscle response to indirect stimulation, before and 60 minutes after separately addition of lidocaine, racemic bupivacaine and rocuronium and the association of local anesthetics - rocuronium; 2) membrane potentials (MP) and miniature end-plate potentials (MEPP). RESULTS: Lidocaine and bupivacaine separately didn't alter the amplitude of muscle response and MP. In preparations previously exposed to lidocaine and racemic bupivacaine, the rocuronium blockade was significantly larger (90.10 ± 9.15% and 100%, respectively), in relation to the produced by rocuronium separately (73.12 ± 9.89%). Lidocaine caused an increase in the frequency of MEPP, being followed by blockade; racemic bupivacaine produced decrease being followed by blockade. CONCLUSIONS: Local anesthetics potentiated the blockade caused by rocuronium. The alterations of MEPP identify presynaptic action.

Phrenic nerve-diaphragm preparations in relation to temperature and hibernation

1961 ◽  
Vol 200 (3) ◽  
pp. 565-571 ◽  
Author(s):  
Frank E. South
Keyword(s):  
Mechanical Properties ◽  
Neuromuscular Blockade ◽  
Phrenic Nerve ◽  
Neuromuscular Transmission ◽  
Incubation Temperature ◽  
Diaphragm Muscle ◽  
Muscle Tissues ◽  
Contraction And Relaxation ◽  
Incubation Temperatures ◽  
And Control

Electrical and mechanical properties, as correlates of incubation temperature, of phrenic nerve-diaphragm preparations obtained from hibernating and control hamsters and from rats were examined. Six incubation temperatures, ranging from 5° to 38°C, were used. Nerves of rats evidenced much steeper temperature functions than did either hamster group, with respect to irritability, spike voltage and conduction velocity such that they were inexcitable at 5°C. The hibernating and control hamster groups behaved quite similarly to each other in these respects. Neuromuscular blockade occurred at 10°C in the rat preparations and at 5°C of the control hamster preparations but in no case did it occur among those of hibernating animals. Similar or analogous differences were apparent in diaphragm muscle tissues insofar as irritability, tension production and rates of contraction and relaxation are concerned. These observations were taken to demonstrate the existence of phylogenetic adaptations correlated with the ability of hamsters to hibernate as well as the probable necessity for a prehibernal acclimatization of such mechanisms as neuromuscular transmission on the part of these animals.

scholarly journals Phenobarbital influence on neuromuscular block produced by rocuronium in rats

2008 ◽  
Vol 23 (4) ◽  
pp. 343-347 ◽  
Author(s):  
Angélica de Fátima de Assunção Braga ◽  
Caroline Coutinho de Barcelos ◽  
Franklin Sarmento da Silva Braga ◽  
Samanta Cristina Antoniassi Fernandes ◽  
Yoko Oshima Franco ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Neuromuscular Blockade ◽  
Neuromuscular Block ◽  
Cytochrome B5 ◽  
Muscle Response ◽  
In Vivo Experiments ◽  
Hepatic Microsomes ◽  
Enzymatic Induction

PURPOSE: To evaluate in vitro and in vivo neuromuscular blockade produced by rocuronium in rats treated with Phenobarbital and to determine cytochrome P450 and cytochrome b5 concentrations in hepatic microsomes. METHODS: Thirty rats were included in the study and distributed into 6 groups of 5 animals each. Rats were treated for seven days with phenobarbital (20 mg/kg) and the following parameters were evaluated: 1) the amplitude of muscle response in the preparation of rats exposed to phenobarbital; 2) rocuronium effect on rat preparation exposed or not to phenobarbital; 3) concentrations of cytochrome P450 and cytochrome b5 in hepatic microsomes isolated from rats exposed or not to phenobarbital. The concentration and dose of rocuronium used in vitro and in vivo experiments were 4 µg/mL and 0,6 mg/kg, respectively. RESULTS: Phenobarbital in vitro and in vivo did not alter the amplitude of muscle response. The neuromuscular blockade in vitro produced by rocuronium was significantly different (p=0.019) between exposed (20%) and not exposed (60%) rats; the blockade in vivo was significantly greater (p=0.0081) in treated rats (93.4%). The enzymatic concentrations were significantly greater in rats exposed to phenobarbital. CONCLUSIONS: Phenobarbital alone did not compromise neuromuscular transmission. It produced enzymatic induction, and neuromuscular blockade in vivo produced by rocuronium was potentiated by phenobarbital.

Fatigue of isolated rat diaphragm: role of impaired neuromuscular transmission

1986 ◽  
Vol 61 (3) ◽  
pp. 1077-1083 ◽  
Author(s):  
T. K. Aldrich ◽  
A. Shander ◽  
I. Chaudhry ◽  
H. Nagashima
Keyword(s):  
Neuromuscular Blockade ◽  
Phrenic Nerve ◽  
Neuromuscular Transmission ◽  
Low Frequency ◽  
Rat Diaphragm ◽  
Direct Stimulation ◽  
Low Frequency Stimulation ◽  
Before And After ◽  
Frequency Stimulation ◽  
Isolated Rat

We compared the contributions of impaired neuromuscular transmission (transmission fatigue) and impaired muscle contractility (contractile fatigue) to fatigue of the isolated rat diaphragm. To make this comparison, we measured the differences in active tension elicited by direct muscle stimulation and by indirect (phrenic nerve) stimulation before and after fatigue induced by indirect supramaximal stimulation at varying frequencies and durations. Transmission fatigue was observed after all experimental protocols. Although significant contractile fatigue was not demonstrated after brief periods of low-frequency stimulation (6 min, 15 Hz, 25% duty cycle), it was present after longer or higher frequency stimulation. We repeated the direct stimulation in the presence of neuromuscular blockade with 6 microM d-tubocurarine to demonstrate that a reduced response to stimulation of intramuscular branches of the phrenic nerve during direct stimulation was not responsible for the apparent contractile fatigue. Since we found significant decreases in the response to direct stimulation even after neuromuscular blockade, we could verify the presence of contractile fatigue. We conclude that both contractile and transmission fatigue can occur in the isolated rat diaphragm and that transmission fatigue is a much more important factor after brief periods of fatiguing contractions.

scholarly journals Diaphragm neuromuscular transmission failure in aged rats

2019 ◽  
Vol 122 (1) ◽  
pp. 93-104 ◽  
Author(s):  
Matthew J. Fogarty ◽  
Maria A. Gonzalez Porras ◽  
Carlos B. Mantilla ◽  
Gary C. Sieck
Keyword(s):  
Nerve Stimulation ◽  
Phrenic Nerve ◽  
Neuromuscular Transmission ◽  
Motor Units ◽  
Diaphragm Muscle ◽  
Muscle Stimulation ◽  
Transmission Failure ◽  
Old Rats ◽  
Motor Neuron Loss ◽  
Fast Twitch

In aging Fischer 344 rats, phrenic motor neuron loss, neuromuscular junction abnormalities, and diaphragm muscle (DIAm) sarcopenia are present by 24 mo of age, with larger fast-twitch fatigue-intermediate (type FInt) and fast-twitch fatigable (type FF) motor units particularly vulnerable. We hypothesize that in old rats, DIAm neuromuscular transmission deficits are specific to type FInt and/or FF units. In phrenic nerve/DIAm preparations from rats at 6 and 24 mo of age, the phrenic nerve was supramaximally stimulated at 10, 40, or 75 Hz. Every 15 s, the DIAm was directly stimulated, and the difference in forces evoked by nerve and muscle stimulation was used to estimate neuromuscular transmission failure. Neuromuscular transmission failure in the DIAm was observed at each stimulation frequency. In the initial stimulus trains, the forces evoked by phrenic nerve stimulation at 40 and 75 Hz were significantly less than those evoked by direct muscle stimulation, and this difference was markedly greater in 24-mo-old rats. During repetitive nerve stimulation, neuromuscular transmission failure at 40 and 75 Hz worsened to a greater extent in 24-mo-old rats compared with younger animals. Because type IIx and/or IIb DIAm fibers (type FInt and/or FF motor units) display greater susceptibility to neuromuscular transmission failure at higher frequencies of stimulation, these data suggest that the age-related loss of larger phrenic motor neurons impacts nerve conduction to muscle at higher frequencies and may contribute to DIAm sarcopenia in old rats. NEW & NOTEWORTHY Diaphragm muscle (DIAm) sarcopenia, phrenic motor neuron loss, and perturbations of neuromuscular junctions (NMJs) are well described in aged rodents and selectively affect FInt and FF motor units. Less attention has been paid to the motor unit-specific aspects of nerve-muscle conduction. In old rats, increased neuromuscular transmission failure occurred at stimulation frequencies where FInt and FF motor units exhibit conduction failures, along with decreased apposition of pre- and postsynaptic domains of DIAm NMJs of these units.

Development of an in vitro rat phrenic nerve–diaphragm muscle preparation

2016 ◽  
Vol 81 ◽  
pp. 364
Author(s):  
Steve Roof ◽  
Carlos del Rio ◽  
Popat Patil ◽  
Steven Strauch ◽  
Robert Hamlin
Keyword(s):  
Phrenic Nerve ◽  
Diaphragm Muscle ◽  
Muscle Preparation

The Effect of Replacement of Potassium by Cesium Ions on Neuromuscular Blockade of the Rat Phrenic Nerve – Diaphragm Preparation In Vitro

1974 ◽  
Vol 52 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Andrew Korey ◽  
John T. Hamilton
Keyword(s):  
Intracellular Recording ◽  
Mechanical Response ◽  
Krebs Solution ◽  
Rat Diaphragm ◽  
Cesium Ions ◽  
End Plate ◽  
Blocking Agents ◽  
Potassium Replacement ◽  
Indirect Stimulation

The effect of potassium replacement by cesium in the rat diaphragm preparations has been investigated using conventional intracellular recording techniques; end-plate potentials (EPP's) recorded in modified Krebs' solution with lowered Ca2+ and high Mg2+ were increased until twitching in response to indirect stimulation was restored. This increase in amplitude of the EPP was not acccompanied by any change in the magnitude or frequency of miniature end-plate potentials (MEPP's) suggesting that Cs+ is acting presynaptically to increase evoked release of transmitter. Similar augmentations of EPP's were observed in preparations paralyzed with d-tubocurarine, gallamine, pancuronium, or decamethonium. Parallel studies showed that the mechanical response of the preparations returned towards control values after K+ substitution by Cs+ in diaphragms that were blocked by the above agents but not those blocked by hemicholinium.The results are consistent with the conclusion that the presynaptic action of cesium can overcome directly any effect that the clinically used blocking agents may have on presynaptic sites and that the increased release of transmitter by cesium is sufficient to overcome indirectly the depressant effects of the blocking agents at postsynaptic end-plate receptors.

Effect of hypoxia on neuromuscular transmission in the developing diaphragm

1994 ◽  
Vol 76 (2) ◽  
pp. 708-713 ◽  
Author(s):  
A. R. Bazzy
Keyword(s):  
Nerve Stimulation ◽  
Phrenic Nerve ◽  
Neuromuscular Transmission ◽  
Ringer Solution ◽  
Diaphragm Muscle ◽  
Control Force ◽  
Force Response ◽  
Direct Stimulation ◽  
Frequency Of Stimulation ◽  
Predominant Effect

To study the effects of hypoxia on neuromuscular transmission in the developing diaphragm, phrenic nerve-hemidiaphragm preparations were obtained from newborn (4–9 days) and older (22–30 days) rats. Diaphragms were stimulated directly or indirectly (via the nerve) for 1 s at frequencies of 10–80 Hz. Force generated in response to stimulation was measured during perfusion of oxygenated Ringer solution (control) and Ringer solution bubbled with 95% N2–5% CO2 (hypoxia). After 45 min of hypoxia, the force response of the older diaphragms to direct stimulation had decreased to approximately 50% of control at > or = 40 Hz; however, when stimulation occurred via the nerve at these frequencies only 15–20% of control force was generated. In the newborn diaphragms, the force decrement after similar or longer periods of hypoxia (< or = 90 min) was 30– 40% irrespective of the route or frequency of stimulation. After 15 min of reoxygenation, the force response to both muscle and nerve stimulation recovered completely in the older diaphragms but only partially in the newborn diaphragms (range 77% of control at 50 Hz to 95% of control at 10 Hz). These data suggest that in the newborn diaphragm 1) neuromuscular transmission is more resistant to the effects of hypoxia than the older diaphragm and 2) the predominant effect of hypoxia is peripheral in the diaphragm muscle fibers, whereas in the older diaphragm the effect is before or at the neuromuscular junction.

Effects of isoeugenol on in vitro neuromuscular blockade of rat phrenic nerve-diaphragm preparations

2003 ◽  
Vol 64 (6) ◽  
pp. 690-693 ◽  
Author(s):  
J. Carina Ingvast-Larsson ◽  
V. Charlotte Axen ◽  
Anders K. Kiessling
Keyword(s):  
Neuromuscular Blockade ◽  
Phrenic Nerve

Developmental changes in neuromuscular transmission in the rat diaphragm

1991 ◽  
Vol 71 (1) ◽  
pp. 280-286 ◽  
Author(s):  
J. D. Feldman ◽  
A. R. Bazzy ◽  
T. R. Cummins ◽  
G. G. Haddad
Keyword(s):  
Phrenic Nerve ◽  
Neuromuscular Transmission ◽  
Peak Force ◽  
Neonatal Rat ◽  
Maximum Force ◽  
Muscle Stimulation ◽  
Rat Diaphragm ◽  
Stimulus Train ◽  
Old Rats

Neuromuscular transmission was studied in diaphragms from rats of three ages, 4–7 days old, 11–12 days old, and adults with the use of an in vitro phrenic nerve-hemidiaphragm preparation. Each hemidiaphragm was stimulated via either muscle or nerve with 1-s stimulus trains at frequencies from 10 to 100 Hz. The patterns of force development obtained in response to the two routes of stimulation were compared for each group. Diaphragms from adults developed maximum force in response to stimulation of approximately 40 Hz with no significant decrease in force at higher frequencies. Within each stimulus train, once peak force was achieved, it was maintained for the remainder of the stimulus and responses to nerve and muscle stimulation were almost identical. In contrast, diaphragms from 4- to 7-day-old rats developed maximum force at approximately 20 Hz; stimulation at greater than or equal to 60 Hz induced significantly less peak force. This decrease in peak force at higher frequencies was significantly larger for nerve than for muscle stimulation. In addition, during each nerve stimulus train diaphragms from 4- to 7-day-old rats were unable to maintain peak force, which decreased at frequencies greater than 20 Hz. The decrease in force reached approximately 50% of peak at stimulation frequencies greater than or equal to 60 Hz. Diaphragms from 11- to 12-day-old rats showed intermediate responses. Based on the responses to phrenic nerve stimulation, we conclude that the neonatal rat diaphragm shows marked neuromuscular transmission failure that is not seen in the adult.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Neostigmine in the treatment of snake accidents caused by Micrurus frontalis: report of two cases

1996 ◽  
Vol 38 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Oswaldo Vital Brazil ◽  
Ronan José Vieira
Keyword(s):  
Neuromuscular Blockade ◽  
Neuromuscular Transmission ◽  
Artificial Respiration ◽  
Rapid Rate ◽  
Southern Brazil ◽  
Coral Snake ◽  
Present Communication ◽  
End Plate ◽  
Rate Of Absorption

Antivenom in order to be effective in the treatment of coral snake accidents must be injected very soon after the bite owing to the rapid rate of absorption of the venom neurotoxins. As this is not always possible, other forms of treatment besides serotherapy must be employed to avoid asphyxia and death. Neostigmine and artificial respiration are used for this purpose. Neostigmine restores neuromuscular transmission if the venom-induced blockade results from a reversible interaction of its neurotoxins with the end-plate receptors. This is the mechanism of the neuromuscular blockade produced by the venom of M. frontalis snakes from centereastern and southern Brazil, and Argentine. Neostigmine is able, therefore, to antagonize the blockade, and has been shown to be very effective in the treatment of the experimental envenomation of dogs and monkeys. In the present communication, two cases of M. frontalis accidents treated with antivenom and neostigmine are reported. In both, neostigmine was successful in producing regression of the paralysis, confirming the effectiveness shown in the treatment of the poisoning induced in animals by M. frontalis venom.

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