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British Journal of Pharmacology and... Mar 1949
Topics: Cholinesterases; Hostility; Tubocurarine
PubMed: 18113150
DOI: 10.1111/j.1476-5381.1949.tb00512.x -
Anesthesiology Dec 1971
Topics: Adolescent; Adult; Drug Interactions; Electric Stimulation; Gallamine Triethiodide; Humans; Injections, Intravenous; Middle Aged; Neuromuscular Junction; Succinylcholine; Time Factors; Tubocurarine; Ulnar Nerve
PubMed: 5166393
DOI: 10.1097/00000542-197112000-00003 -
British Journal of Anaesthesia Aug 1986In order to evaluate the sensitivity of different muscle types to neuromuscular blocking drugs, a system using mouse muscles in vitro was developed and applied to detect... (Comparative Study)
Comparative Study
In order to evaluate the sensitivity of different muscle types to neuromuscular blocking drugs, a system using mouse muscles in vitro was developed and applied to detect changes in drug sensitivity in relation to age. The effect of pancuronium and tubocurarine on initial twitch and on the ratio of fourth twitch to first twitch (T4/T1) of a train-of-four at 2 Hz were compared in fast-twitch, slow-twitch and respiratory muscles in the mouse. The muscles used were: extensor digitorum longus (EDL), soleus (SOL) and diaphragm (DIA). For both drugs the order of decreasing sensitivity was EDL greater than SOL greater than DIA. This result was the same whether first twitch or T4/T1 was used, although the latter was a more sensitive indicator. The sensitivity of neuromuscular block was less in muscles from old (30-33 month) animals than in the equivalent muscles from young (8-12 month) animals.
Topics: Aging; Animals; Diaphragm; In Vitro Techniques; Male; Mice; Muscle Contraction; Muscles; Neuromuscular Junction; Pancuronium; Synaptic Transmission; Tubocurarine
PubMed: 3015178
DOI: 10.1093/bja/58.8.909 -
The Journal of Physiology Jul 1973The effects of eserine and D-tubocurarine on the axon and Schwann cell membrane potentials have been studied in the giant nerve fibre of the squid.1. The addition of...
The effects of eserine and D-tubocurarine on the axon and Schwann cell membrane potentials have been studied in the giant nerve fibre of the squid.1. The addition of eserine at concentrations of up to 10(-4)M to the external sea-water medium has no appreciable effects on either the Schwann cell electrical potential of unstimulated nerve fibres or on the resting and action potentials of the axon.2. However, eserine at a concentration of 10(-9)M prolongs the long-lasting Schwann cell hyperpolarizations which follow the conduction of impulse trains by the axon.3. Higher concentrations of eserine (10(-7), 10(-4)M) decrease and block the long-lasting effects of nerve impulse train conduction.4. D-tubocurarine at concentrations of up to 10(-5)M has no appreciable effect on the resting and action potentials of the axon.5. However, D-tubocurarine at a concentration of 10(-9)M blocks completely the hyperpolarizing effects of nerve impulse trains on the Schwann cell electrical potential.6. In addition to its blocking action, D-tubocurarine induces transient hyperpolarizations in the Schwann cells of unstimulated nerve fibres both in intact fibres and in slitted preparations.7. These findings suggest that a cholinergic system, which may be located at the axon-Schwann cell boundary, is involved in the genesis of the long-lasting Schwann cell hyperpolarization caused by the conduction of nerve impulse trains by the axon.
Topics: Action Potentials; Animals; Axons; Decapodiformes; Electric Stimulation; Membrane Potentials; Neural Conduction; Physostigmine; Schwann Cells; Tubocurarine
PubMed: 4733485
DOI: 10.1113/jphysiol.1973.sp010264 -
Anesthesiology May 1983The in vivo cat soleus and gastrocnemius muscles were used to compare isometric contraction strength and the train-of-four (T4) response (2 Hz for 2 s) of two muscle... (Comparative Study)
Comparative Study
The in vivo cat soleus and gastrocnemius muscles were used to compare isometric contraction strength and the train-of-four (T4) response (2 Hz for 2 s) of two muscle types (fast and slow) during onset of competitive neuromuscular blockade in order to determine the extent of the correlation between twitch depression and T4 fade. Prior to drug administration the muscles that were studied differed significantly in that the T4 ratio was 1.0 in the gastrocnemius and only 0.87 in the soleus. Three competitive neuromuscular-blocking agents were compared: d-tubocurarine, pancuronium, and vecuronium. d-Tubocurarine was found to produce a close correlation between the degrees of twitch strength depression and T4 for both muscles. However, these muscles demonstrated significantly different ED50 values (105 micrograms/kg for gastrocnemius, 150 micrograms/kg for soleus). Pancuronium also produced a similar relationship between twitch strength depression and T4 decrement for each muscle. In this case, however, there was little difference in their ED50 values for twitch depression (11.5 micrograms/kg for gastrocnemius, 13 micrograms/kg for soleus). The effects of vecuronium were quite different from the other two muscle relaxants. Although vecuronium produced a comparable correlation between twitch tension and T4 fade in fast muscle, no such relationship was found to exist in slow muscle. Even when the twitch strength was blocked to 18% of control, the soleus T4 response was depressed to only 75% of control. These results highlight major differences among competitive neuromuscular-blocking agents and suggest multiple sites of action.
Topics: Animals; Cats; Dose-Response Relationship, Drug; Electric Stimulation; Female; Male; Muscle Contraction; Pancuronium; Tubocurarine; Vecuronium Bromide
PubMed: 6132567
DOI: 10.1097/00000542-198305000-00004 -
British Journal of Anaesthesia Jun 1981Cumulation and interaction of neuromuscular blocking effects of neomycin and tubocurarine were determined on responses of the tibialis anterior muscle of the...
Cumulation and interaction of neuromuscular blocking effects of neomycin and tubocurarine were determined on responses of the tibialis anterior muscle of the anaesthetized cat to indirect stimulation. Neuromuscular block produced by neomycin was cumulative despite rapid and apparent full recovery of twitch tension and an interval of 3 h between dose-response studies. Ed50 of neomycin on twitch tension decreased (P less than 0.05) from 22 +/- 4 mg kg-1 to 12 +/- 3 mg kg-1 after 3 h; marked post-tetanic exhaustion was observed after the antibiotic. Neuromuscular block (80-90%) with neomycin 25-30 mg kg-1 followed by full recovery and 3-h interval decreased (P less than 0.05) the ED50 of tubocurarine on twitch tension from 0.2 +/- 0.02 mg kg-1 to 0.13 +/- 0.03 mg kg-1. Tubocurarine exhibited no cumulative effects at intervals of 2 h and did not significantly affect the response of twitch and tetanic tension to neomycin after an interval of 2 h. It is concluded that neomycin increases the sensitivity of neuromuscular transmission to tubocurarine despite apparently normal responses to indirect stimulation and that the post-tetanic exhaustion observed with neomycin alone may explain apnoea reported in patients with the antibiotic.
Topics: Animals; Cats; Dose-Response Relationship, Drug; Drug Synergism; Female; Male; Neomycin; Neuromuscular Junction; Time Factors; Tubocurarine
PubMed: 7248120
DOI: 10.1093/bja/53.6.571 -
British Medical Journal Apr 1947
Topics: Curare; Electric Stimulation Therapy; Humans; Seizures; Thiopental; Tubocurarine
PubMed: 20248016
DOI: 10.1136/bmj.1.4500.445 -
British Journal of Pharmacology and... Mar 1949
Topics: Anesthesia; Anesthesia, Local; Anesthetics, Local; Animals; Guinea Pigs; Intestines; Rabbits; Tubocurarine
PubMed: 18113151
DOI: 10.1111/j.1476-5381.1949.tb00513.x -
British Journal of Anaesthesia Dec 1969
Comparative Study
Topics: Anesthesia, General; Drug Synergism; Electric Stimulation; Ethnicity; Humans; London; New York; Succinylcholine; Synaptic Transmission; Tubocurarine
PubMed: 4312426
DOI: 10.1093/bja/41.12.1041 -
Anesthesiology Nov 1978To determine the effects of hypothermia on the pharmacokinetics and pharmacodynamics of d-tubocurarine (dTc), serum, biliary, and urinary concentrations were determined...
To determine the effects of hypothermia on the pharmacokinetics and pharmacodynamics of d-tubocurarine (dTc), serum, biliary, and urinary concentrations were determined and twitch tension monitored following intravenous administration of dTc, 0.7 mg/kg, at 39 (n = 5), 34 (n = 5), and 28 C (n = 6) in cats anesthetized with chloralose and urethane. Time from injection of dTc to maximum neuromuscular blockade was prolonged by hypothermia (28 C). Similarly, moderate (28 C) but not mild (34 C) hypothermia delayed recovery from paralysis. The serum half-life was prolonged 76% and the serum clearance rate decreased 60% by hypothermia (28 C). The combined biliary and urinary elimination of dTc was decreased 47% at 28 C compared with 34 and 39 C. The serum concentration of dTc necessary for neuromuscular blockade was less at 39 C (ED50 0.87 microgram/ml) than at 34 or 28 C (ED50 1.13 microgram/ml). It is concluded that, in vivo, hypothermia antagonizes a dTc-induced neuromuscular blockade but decreases the elimination of dTc. At 28 C the net effect is a prolongation of neuromuscular blockade.
Topics: Animals; Cats; Hypothermia; Kinetics; Neuromuscular Junction; Time Factors; Tubocurarine
PubMed: 736287
DOI: 10.1097/00000542-197811000-00005