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1.
Science ; 212(4499): 1170-2, 1981 Jun 05.
Article in English | MEDLINE | ID: mdl-7233212

ABSTRACT

Gallamine triethiodide (Flaxedil) is commonly used as a neuromuscular blocking agent. Voltage-clamp studies show that gallamine also directly affects amphibian and mammalian myelinated nerve fibers. Externally, gallamine is about five times more potent than tetraethylammonium in blocking potassium conductance, where this is present, but has no effect on the sodium channel. Internal application slows sodium inactivation, which in addition is often incomplete. At positive potentials, gallamine can occlude sodium channels, thereby almost eliminating outward sodium currents.


Subject(s)
Gallamine Triethiodide/pharmacology , Myelin Sheath/physiology , Neurons/physiology , Animals , Electric Conductivity , Membrane Potentials/drug effects , Myelin Sheath/drug effects , Pancuronium/pharmacology , Potassium/pharmacology , Ranidae , Rats , Sodium/metabolism , Tetraethylammonium Compounds/pharmacology
2.
Eur J Pharmacol ; 569(1-2): 37-40, 2007 Aug 13.
Article in English | MEDLINE | ID: mdl-17588565

ABSTRACT

Neuromuscular blocking drugs produce muscle weakness by interaction with nicotinic-acetylcholine receptors. Cardiovascular side effects have been reported. In this study the neuromuscular blocking drug vecuronium and the controls gallamine and pancuronium slowed the rate of atropine induced [(3)H]N-methylscopolamine dissociation from Chinese hamster ovary cells expressing recombinant human muscarinic M2 receptors K(off) values min(-1); vecuronium (125 nM), atropine 0.45+/-0.07+blocker 0.04+/-0.02; gallamine (21 nM), atropine 0.42+/-0.05+blocker 0.15+/-0.04; pancuronium(21 nM), atropine 0.36+/-0.03+blocker 0.03+/-0.01). These data indicate that vecuronium, gallamine and pancuronium interact with an allosteric site on the muscarinic M2 receptor (located on the heart) and this may explain some of their cardiac side effects.


Subject(s)
Neuromuscular Blocking Agents/pharmacology , Pancuronium/pharmacology , Receptor, Muscarinic M2/metabolism , Vecuronium Bromide/pharmacology , Allosteric Regulation/drug effects , Animals , Atropine/pharmacology , Binding, Competitive/drug effects , CHO Cells , Cricetinae , Cricetulus , Gallamine Triethiodide/pharmacology , Humans , Kinetics , Muscarinic Antagonists/pharmacology , N-Methylscopolamine/metabolism , Pancuronium/metabolism , Radioligand Assay , Receptor, Muscarinic M2/antagonists & inhibitors , Receptor, Muscarinic M2/genetics , Recombinant Proteins/metabolism , Tritium
3.
Br J Pharmacol ; 46(3): 514-6, 1972 Nov.
Article in English | MEDLINE | ID: mdl-4511872

ABSTRACT

The motor nerve outflow in the pithed rat was stimulated from the spinal column and contractions of individual skeletal muscles recorded. The preparation is anaesthetic-free and well suited to a study of muscle relaxants.


Subject(s)
Muscle Contraction/drug effects , Spinal Nerves/physiology , Animals , Cordotomy , Decamethonium Compounds/pharmacology , Electric Stimulation , Gallamine Triethiodide/pharmacology , Pancuronium/pharmacology , Rats , Tubocurarine/pharmacology
4.
Br J Pharmacol ; 84(1): 3-5, 1985 Jan.
Article in English | MEDLINE | ID: mdl-3838488

ABSTRACT

The muscarinic receptor mediating vasodilatation of the rabbit aorta and dog femoral artery has been assessed using muscarinic antagonists. With the exception of pirenzepine, the antagonist affinities were similar to those reported for the ileal receptors and dissimilar to those reported for the atrial receptors. Pirenzepine exhibited an affinity (7.54) intermediate between that reported for the CNS receptors (8.4) and that reported for the ileal receptors (6.77). This value for pirenzepine was confirmed using acetylcholine as the agonist and using the dog femoral artery as the vascular tissue. It is concluded that the muscarinic receptor profile mediating vasodilatation is not easily accommodated into the current receptor classification.


Subject(s)
Parasympatholytics/pharmacology , Receptors, Muscarinic/drug effects , Vasodilation/drug effects , Acetylcholine/pharmacology , Animals , Aorta, Thoracic/drug effects , Atropine/pharmacology , Benzodiazepinones/pharmacology , Carbachol/pharmacology , Dogs , Female , Femoral Artery/drug effects , Gallamine Triethiodide/pharmacology , In Vitro Techniques , Male , Pancuronium/pharmacology , Phenethylamines/pharmacology , Piperidines/pharmacology , Pirenzepine , Rabbits
5.
Br J Pharmacol ; 54(1): 91-100, 1975 May.
Article in English | MEDLINE | ID: mdl-166720

ABSTRACT

1. In the rat isolated diaphragm preparation hexamethonium and other low potency competitive antagonists of acetylcholine (ACh), including gallamine and hyoscine butylbromide, reverse block by the potent antagonists tubocurarine, pancuronium and alcuronium. 2. In the presence of tubocurarine, hexamethonium increases the amplitude of the end-plate potential without increasing the quantal content. It enhances the response to ACh applied iontophoretically to the end-plate but does not enhance the response to ACh applied in the bath. 3. The anti-curare effect of hexamethonium is abolished in the diaphragm of the rat, guinea-pig and mouse by inhibitors of acetylcholinesterase. The effect is not observed in the indirectly stimulated toad sartorius muscle. 4. The effect is explained if tubocurarine does not dissociate appreciably in the time taken for ACh to achieve high occupancy of receptors, so that a fraction of receptors is completely excluded from occupation by ACh. Equilibration with hexamethonium reduces the fraction excluded by tubocurarine and the transmitter now competes with hexamethonium for more receptors and produces a larger response. 5. On the basis of this explanation the half-time for dissociation of tubocurarine must be about 1 millisecond. It follows that tubocurarine does not act competitively with ACh at synapses when transmitter action is sufficiently brief, and that its binding to the receptor is probably diffusion-limited.


Subject(s)
Hexamethonium Compounds/pharmacology , Neuromuscular Junction/drug effects , Receptors, Drug , Synaptic Transmission/drug effects , Tubocurarine/antagonists & inhibitors , Acetylcholine/antagonists & inhibitors , Alcuronium/pharmacology , Animals , Anura , Binding, Competitive , Bis-Trimethylammonium Compounds/pharmacology , Chlorisondamine/pharmacology , Cholinesterase Inhibitors , Drug Interactions , Gallamine Triethiodide/pharmacology , Guinea Pigs , Mice , Pancuronium/pharmacology , Rats , Scopolamine/pharmacology , Tropanes/pharmacology , Tubocurarine/pharmacology
6.
Biochem Pharmacol ; 39(3): 415-20, 1990 Feb 01.
Article in English | MEDLINE | ID: mdl-1968337

ABSTRACT

There have been reports of hypotension and flushing following vecuronium administration. The etiology of these symptoms, which are similar to those of histamine release, is not clear. The steroidal neuromuscular relaxants (NMRs), unlike muscle relaxants structurally similar to curare, have been shown not to cause histamine release after the administration of typical clinical doses. Histamine levels in plasma reflect a balance between release and catabolism. In humans, histamine N-methyl-transferase (HNMT) is the enzyme primarily degrading for histamine. Therefore, we performed in vitro kinetic studies of purified HNMT to determine the effects of the steroidal and curare-like NMRs and also of gallamine on histamine catabolism. We demonstrated that all NMRs tested were inhibitors of HNMT in vitro. The inhibition was competitive with respect to the cosubstrate S-adenosyl-L-[3H-methyl] methionine, and noncompetitive with respect to histamine. The rank order of inhibition was vecuronium greater than pancuronium greater than gallamine greater than d-tubocurarine greater than metocurine greater than atracurium greater than pipecuronium, with Ki values ranging from 1.2 to 44.8 microM. Our data suggest that HNMT-based radioenzymatic assays for histamine should be susceptible to inhibition by concurrent use of NMRs, particularly vecuronium.


Subject(s)
Histamine N-Methyltransferase/antagonists & inhibitors , Methyltransferases/antagonists & inhibitors , Neuromuscular Blocking Agents/pharmacology , Neuromuscular Nondepolarizing Agents/pharmacology , Androstane-3,17-diol/analogs & derivatives , Androstane-3,17-diol/pharmacology , Animals , Atracurium/pharmacology , Gallamine Triethiodide/pharmacology , Kidney/enzymology , Pancuronium/pharmacology , Pipecuronium , Piperazines/pharmacology , Rats , Tubocurarine/analogs & derivatives , Tubocurarine/pharmacology , Vecuronium Bromide/pharmacology
7.
Chest ; 83(2 Suppl): 349-51, 1983 Feb.
Article in English | MEDLINE | ID: mdl-6129950

ABSTRACT

Administration of tubocurarine, pancuronium, gallamine, or decamethonium into the cisterna magna of chloralosed dogs induced a rise in blood pressure. Clonidine (3 micrograms/kg) administered into the cisterna magna after tubocurarine, pancuronium, or gallamine significantly increased blood pressure; no significant change was found after decamethonium. The pressor response to clonidine after tubocurarine was antagonized by injection of the alpha 1-adrenoceptor-blocking agents AR-C 239 or prazosin into the cisterna magna at low doses prior to injection of clonidine. Yohimbine, a preferential alpha 2-adrenoceptor-blocking agent was ineffective. It is suggested that the pressor response to intracisternal clonidine after intracisternal tubocurarine is due to stimulation of alpha 1-adrenoceptor stimulation.


Subject(s)
Blood Pressure/drug effects , Clonidine/antagonists & inhibitors , Neuromuscular Nondepolarizing Agents/pharmacology , Adrenergic alpha-Antagonists/pharmacology , Animals , Cisterna Magna , Decamethonium Compounds/pharmacology , Dogs , Female , Gallamine Triethiodide/pharmacology , Hypertension/chemically induced , Male , Pancuronium/pharmacology , Prazosin/pharmacology , Pressoreceptors/drug effects , Receptors, Adrenergic, alpha/drug effects , Stimulation, Chemical , Tubocurarine/pharmacology , Yohimbine/pharmacology
8.
J Biochem ; 112(4): 495-502, 1992 Oct.
Article in English | MEDLINE | ID: mdl-1337082

ABSTRACT

Since binding of an agonist to an ionotropic neurotransmitter receptor causes not only channel opening, but also desensitization of the receptor, inhibition of the receptor by the antagonist sometimes becomes very complicated. The transient state kinetics of ligand association and dissociation, and desensitization of the receptor were considered on the basis of the minimal model proposed by Hess' group, and the following possibilities were proposed. 1) When an agonist is simultaneously applied to the receptor with an antagonist whose affinity to the receptor is extremely strong and different from that of the agonist, it is usually impossible to estimate the real inhibition constant exactly from the responses because desensitization of the receptor proceeds before the equilibrium of the ligand binding. Simultaneous addition of the antagonist with strong affinity to the receptor may apparently accelerate inactivation (desensitization) of the receptor. The association rate constant of the antagonist can be estimated by analyses of the rate of the inactivation in the presence and the absence of the antagonist. 2) A preincubated antagonist with a slow dissociation rate constant, i.e., a very effective inhibitor, may cause apparent noncompetitive inhibition of the receptor, since the receptor is desensitized by an agonist as soon as the antagonist dissociates from the receptor and the dissociation of the antagonist from the receptor becomes the rate-determining step. A nicotinic acetylcholine receptor (nAChR) was expressed in Xenopus oocytes by injecting mRNA prepared from Electrophorus electricus electroplax and used for the experiments on inhibition by an antagonist.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Receptors, Neurotransmitter/antagonists & inhibitors , Acetylcholine/pharmacology , Animals , Binding, Competitive , Female , Gallamine Triethiodide/metabolism , Gallamine Triethiodide/pharmacology , Ion Transport/drug effects , Ion Transport/physiology , Kinetics , Mathematical Computing , Oocytes/drug effects , Oocytes/physiology , Pancuronium/metabolism , Pancuronium/pharmacology , Receptors, Glycine , Receptors, Neurotransmitter/metabolism , Receptors, Neurotransmitter/physiology , Strychnine/pharmacology , Time Factors , Tubocurarine/metabolism , Tubocurarine/pharmacology , Xenopus/physiology
9.
Surv Ophthalmol ; 21(6): 494-500, 1977.
Article in English | MEDLINE | ID: mdl-331534

ABSTRACT

General anesthetics may have diverse effects on intraocular pressure, possibly leading to serious complications such as vitreous loss and iris prolapse. Clinical and research findings on the effects of depolarizing and nondepolarizing agents are discussed, and methods of avoiding or counteracting adverse reactions are summarized.


Subject(s)
Anesthesia, General/adverse effects , Anesthetics/adverse effects , Intraocular Pressure/drug effects , Anesthesia, Inhalation/adverse effects , Anesthetics/pharmacology , Aqueous Humor/drug effects , Child , Gallamine Triethiodide/adverse effects , Gallamine Triethiodide/pharmacology , Humans , Ketamine , Muscle Relaxants, Central , Oculomotor Muscles/drug effects , Pancuronium/adverse effects , Pancuronium/pharmacology , Succinylcholine/adverse effects , Succinylcholine/pharmacology , Tubocurarine/adverse effects , Tubocurarine/pharmacology
10.
J Clin Pharmacol ; 30(2): 170-3, 1990 Feb.
Article in English | MEDLINE | ID: mdl-2312770

ABSTRACT

The pathophysiology of poliomyelitis and the recognition of the "post-polio syndrome" suggest that susceptibility to muscle relaxants of patients previously affected by this disease, may be altered. We compared the effects of d-tubocurarine (dTc), pancuronium (P), and gallamine (G) on two pediatric surgical patient groups: one with a previous history of polio disease, occurring 6 to 12 years prior admission (N = 30, average age: 13 yrs, weight: 43 kg) and another without history of this disease (N = 51, average age: 11 yrs, weight: 39 kg). Following uniform premedication, thiopental, N2O/O2 + narcotic (fentanyl) anesthesia was given for reconstructive surgeries. For orotracheal intubation the patients were briefly paralyzed with 0.7 mg/kg suxamethonium. The thumb adductor responses to supramaximal 1/5 Hz impulses (continuous mode) and to 50 Hz tetanic stimuli (periodically) were recorded. After full recovery from the effect of suxamethonium (100% return of the neurally evoked muscle response) cumulative ED50 values and the recovery index (minutes elapsed from 90% to 50% block of the twitch response) of the three nondepolarizing muscle relaxants were determined. The ED50 of dTc and P were significantly lower with both neuromuscular responses in the post-polio groups (dTc, N = 12 and P, N = 10) as compared to the controls (N = 24 and 18). A tendency toward lower ED50 values in the polio group was also observed with G (N = 6). The differences, however, as compared to the control group (N = 9) were not significant (P less than .2). Recovery times were identical in the polio versus non-polio groups.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Gallamine Triethiodide/pharmacology , Pancuronium/pharmacology , Poliomyelitis/physiopathology , Tubocurarine/pharmacology , Adolescent , Child , Humans , Time Factors
11.
Brain Res ; 400(1): 133-8, 1987 Jan 01.
Article in English | MEDLINE | ID: mdl-3493056

ABSTRACT

The effect of muscarinic antagonists was studied on the muscarinic slow IPSP (inhibitory postsynaptic potential) and slow EPSP (excitatory postsynaptic potential) in bullfrog sympathetic ganglia using the sucrose-gap recording method. Pirenzepine, alcuronium and atropine reduced slow IPSP amplitude more than slow EPSP amplitude. The most selective antagonists studied were pancuronium and gallamine which blocked or substantially reduced the slow IPSP without significantly affecting slow EPSP amplitude. The results suggest that the muscarinic inhibitory response may involve a different muscarinic receptor subtype, and/or receptor-ion-channel complex, than the muscarinic excitatory response.


Subject(s)
Ganglia, Sympathetic/physiology , Receptors, Muscarinic/physiology , Alcuronium/pharmacology , Animals , Atropine/pharmacology , Electric Stimulation , Evoked Potentials/drug effects , Gallamine Triethiodide/pharmacology , Ganglia, Sympathetic/drug effects , In Vitro Techniques , Pancuronium/pharmacology , Pirenzepine/pharmacology , Rana catesbeiana , Receptors, Muscarinic/drug effects
12.
Eur J Pharmacol ; 438(1-2): 35-43, 2002 Mar 01.
Article in English | MEDLINE | ID: mdl-11906708

ABSTRACT

Administration of certain combinations of non-depolarising muscle relaxants produces greater than expected neuromuscular blockade. Synergistic effects may be explained by drug interactions with the postsynaptic muscle nicotinic acetylcholine receptor. To investigate this hypothesis, the adult mouse muscle nicotinic acetylcholine receptor (alpha(2)beta delta epsilon) was heterologously expressed in Xenopus laevis oocytes and activated by the application of acetylcholine (10 microM). The effects of five individually applied muscle relaxants and six combinations of structurally similar and dissimilar compounds were studied. Drug combinations containing equipotent concentrations of two agents were tested and dose-response curves were determined. All compounds tested alone and in combination produced rapid and readily reversible, concentration-dependent inhibition. Isobolographic and fractional analyses indicated additive interactions for all six tested combinations. These findings suggest that synergistic neuromuscular blocking effects, observed for the administration of certain combinations of muscle relaxants, do not result from purely postsynaptic binding events at the muscle nicotinic acetylcholine receptor, but rather from differential actions on pre- and postsynaptic sites.


Subject(s)
Neuromuscular Nondepolarizing Agents/pharmacology , Nicotinic Antagonists/pharmacology , Receptors, Nicotinic/drug effects , Acetylcholine/pharmacology , Animals , Dose-Response Relationship, Drug , Drug Interactions , Electrophysiology , Female , Gallamine Triethiodide/pharmacology , Isoquinolines/pharmacology , Mice , Mivacurium , Oocytes/cytology , Oocytes/drug effects , Oocytes/physiology , Pancuronium/pharmacology , Receptors, Nicotinic/genetics , Receptors, Nicotinic/physiology , Tubocurarine/pharmacology , Vasodilator Agents/pharmacology , Vecuronium Bromide/pharmacology , Xenopus
13.
Naunyn Schmiedebergs Arch Pharmacol ; 335(4): 367-71, 1987 Apr.
Article in English | MEDLINE | ID: mdl-3600815

ABSTRACT

The effects of atropine, pancuronium and gallamine were tested on pre- and post-junctional muscarinic receptors in the lung. Inhibition of bronchoconstriction induced by intravenous injection of acetylcholine (ACh) was used as a measure of post-junctional receptor blockade. All three antagonists reduced ACh-induced bronchoconstriction. The effects were dose-related for atropine and pancuronium and complete inhibition was obtained with 0.01 mg/kg and 10 mg/kg respectively. Gallamine was much less potent than the other two drugs; the inhibitory effect was not dose-related and never exceeded 50% even at a dose of 10 mg/kg. In contrast, blockade of pre-junctional inhibitory muscarinic receptors in pulmonary parasympathetic nerves by these three antagonists, produced potentiation of bronchoconstriction induced by vagal-nerve stimulation. Consequently, the effect of the three antagonists on vagally-induced bronchoconstriction is dependent on the balance between their pre- and post-junctional blocking activity. Gallamine was the most effective and atropine the least effective antagonist for potentiating nerve-induced bronchoconstriction. At doses which produce 100% neuromuscular blockade, both pancuronium (0.04 mg/kg) and gallamine (4 mg/kg) potentiated vagally-induced bronchoconstriction. At these doses, pancuronium doubled and gallamine caused a four-fold increase in vagally-induced bronchoconstriction, despite partial concurrent blockade of muscarinic receptors in the smooth muscle of the airways.


Subject(s)
Gallamine Triethiodide/pharmacology , Lung/innervation , Pancuronium/pharmacology , Parasympatholytics , Receptors, Muscarinic/drug effects , Acetylcholine/pharmacology , Animals , Atropine/pharmacology , Bronchi/drug effects , Electric Stimulation , Guinea Pigs , Heart Rate/drug effects , In Vitro Techniques , Lung/drug effects , Male , Parasympathetic Nervous System/physiology
14.
Naunyn Schmiedebergs Arch Pharmacol ; 329(2): 176-81, 1985 Apr.
Article in English | MEDLINE | ID: mdl-4010794

ABSTRACT

Neuromuscular blocking drugs have a high affinity for muscarinic acetylcholine receptors in the heart atria and ileal smooth muscle. In experiments on homogenates, alcuronium, gallamine, pancuronium, tercuronium and ritebronium inhibited the binding of the muscarinic antagonist (3H)quinuclidinyl benzilate (QNB) to rat heart atria with IC50 values of 0.15-0.53 mumol X 1(-1) and to ileal longitudinal muscles with IC50 values of 0.12-0.45 mumol X 1(-1). d-Tubocurarine and decamethonium inhibited (3H)QNB binding to these tissues with IC50 values of 6.2-8.5 mumol X 1(-1). For each neuromuscular blocking drug, the IC50 values were virtually identical for (3H)QNB displacement in the homogenates of the atria and of the ileal muscle. Alcuronium and gallamine differed from the other blocking agents in that they produced less steep (3H)QNB displacement curves both in the atria and the ileal muscle; Hill coefficients for the binding of alcuronium and gallamine to atrial and ileal homogenates were lower than unity. On isolated atria, gallamine, pancuronium, ritebronium and tercuronium antagonized the inhibition of tension development caused by the muscarinic agonist, methylfurmethide, with Kd values which were of the same order of magnitude as the IC50 values for the displacement of (3H)QNB binding to homogenates; the Kd of alcuronium was 12.5 times higher. d-Tubocurarine and decamethonium did not antagonize the effects of methylfurmethide at concentrations up to 100 mumol X 1(-1). On isolated ileal longitudinal muscle, gallamine and pancuronium antagonized the effects of methylfurmethide with Kd values that were 53 times and 100 times higher than their respective Kd values in the atria.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Heart/drug effects , Muscle, Smooth/drug effects , Neuromuscular Blocking Agents/pharmacology , Receptors, Cholinergic/drug effects , Alcuronium/pharmacology , Animals , Binding, Competitive/drug effects , Decamethonium Compounds/pharmacology , Female , Gallamine Triethiodide/pharmacology , Ileum/drug effects , In Vitro Techniques , Kinetics , Muscle, Smooth/metabolism , Myocardium/metabolism , Neuromuscular Blocking Agents/metabolism , Pancuronium/pharmacology , Piperidines/metabolism , Piperidines/pharmacology , Quaternary Ammonium Compounds/metabolism , Quaternary Ammonium Compounds/pharmacology , Quinuclidinyl Benzilate , Rats , Rats, Inbred Strains , Tubocurarine/pharmacology
15.
Life Sci ; 57(25): 2325-33, 1995.
Article in English | MEDLINE | ID: mdl-7491091

ABSTRACT

The effect of pancuronium pretreatment on the function of the prejunctional muscarinic receptor in guinea-pig trachea was studied by using electrical field stimulation (EFS). The effects of cumulative doses of the muscarinic M2 receptor antagonist gallamine were investigated in tracheal smooth muscle strips from guinea-pigs after addition of pancuronium in vitro and in strips from guinea-pigs which had been pretreated with doses of pancuronium that caused 100% neuromuscular blockade. The results of both types of experiments were compared to those of control groups of the same size. In all strips a dose response curve with cumulative doses of methacholine was made before EFS was switched on. No differences were found between the mean pD2 value and slope of the concentration-response curves of untreated guinea-pigs and animals treated with anaesthetics and pancuronium. The animals showed variable responses to pancuronium. The bath concentration of pancuronium which decreased the EFS-induced contraction to half the original value varied between 14-61 microM. The intravenous dose necessary to paralyze the muscles, varied among the different guinea-pigs from 0.017-0.085 mg.kg-1. The EFS-induced contraction for the concentration range of gallamine 0.32 microM-0.32 mM was found to differ significantly between the strips treated with pancuronium in the organ bath and their control group. For the guinea-pigs anaesthetized and pretreated with pancuronium a significant difference with control was observed at gallamine concentrations ranging from 0.032-0.32 mM. These results show that pancuronium, added to the organ bath as well as administered intravenously to the guinea-pig, masked the inhibitory muscarinic receptor.


Subject(s)
Autoreceptors/drug effects , Neuromuscular Nondepolarizing Agents/pharmacology , Pancuronium/pharmacology , Receptors, Muscarinic/drug effects , Trachea/drug effects , Animals , Female , Gallamine Triethiodide/pharmacology , Guinea Pigs , In Vitro Techniques , Male , Methacholine Chloride/pharmacology , Muscle Contraction/drug effects , Muscle, Smooth/drug effects , Muscle, Smooth/physiology , Trachea/physiology
16.
J Pharm Pharmacol ; 27(10): 721-7, 1975 Oct.
Article in English | MEDLINE | ID: mdl-52704

ABSTRACT

Org 6368 is a homologue of pancuronium bromide. Its interactions with other agents in the cat sciatic nerve-gastrocnemius muscle preparation revealed that paralysis was of the non-depolarizing type. This was confirmed in experiments using avian muscle. Org 6368 is a potent muscle relaxant being 2-4 times as potent as (+)-tubocurarine in the cat. Paralysis in the cat is rapid in onset and of appreciably shorter duration than that of pancuronium and (+)-tubocurarine. Repeated injections of the same dose of Org 6368 show no cumulative effect. Muscle relaxant doses generally cause a slight increase in both blood pressure and heart rate. Although its histamine-releasing capacity is greater than that of pancuronium it is less than that of (+)-tubocurarine. Org 6368 shares with pancuronium a very weak effect on both the muscarinic receptor and ganglionic transmission. Differences in the muscle relaxant profiles of Org 6368 and pancuronium are discussed.


Subject(s)
Neuromuscular Blocking Agents/pharmacology , Pancuronium/analogs & derivatives , Animals , Autonomic Fibers, Preganglionic/physiology , Cats , Chickens , Electric Stimulation , Female , Gallamine Triethiodide/pharmacology , Ganglia, Spinal/drug effects , Guinea Pigs , Hexamethonium Compounds/pharmacology , Histamine Release/drug effects , In Vitro Techniques , Male , Muscles/drug effects , Neuromuscular Junction/drug effects , Pancuronium/pharmacology , Parasympatholytics/pharmacology , Phrenic Nerve/physiology , Sciatic Nerve/physiology , Synaptic Transmission/drug effects , Tubocurarine/pharmacology
17.
Acta Med Okayama ; 51(1): 13-8, 1997 Feb.
Article in English | MEDLINE | ID: mdl-9057930

ABSTRACT

The effect of various non-depolarizing neuromuscular blocking agents (gallamine, pancuronium, vecuronium, d-tubocurarine, metocurine, atracurium and pipecuronium) on [3H]acetylcholine release in the response to field electrical stimulation was investigated in vitro in preparations of the guinea pig right atrium. In this preparation, atropine enhanced and oxotremorine, a muscarinic agonist, reduced the release of [3H] acetylcholine. Atropine reversed the inhibitory effect of oxotremorine in a concentration dependent manner, indicating that there is negative feedback modulation of acetylcholine release from the vagal nerve. While pancuronium, gallamine and atracurium enhanced the release of [3H]acetylcholine, d-tubocurarine, metocurine, vecuronium and pipecuronium did not affect it. Pancuronium and gallamine also reduced the inhibitory effect of oxotremorine and the Kd value of pancuronium for muscarinic receptors located on cholinergic nerve terminals was 2.31 microM. These findings indicate that pancuronium and gallamine enhanced the release of acetylcholine from the atrial parasympathetic nerve, probably by inhibiting presynaptic muscarinic receptors.


Subject(s)
Acetylcholine/metabolism , Heart Atria/metabolism , Neuromuscular Nondepolarizing Agents/pharmacology , Animals , Atracurium/pharmacology , Atrial Function, Right/physiology , Electric Stimulation , Female , Gallamine Triethiodide/pharmacology , Guinea Pigs , Heart Atria/drug effects , In Vitro Techniques , Male , Pancuronium/pharmacology , Parasympathetic Nervous System/physiology , Pipecuronium/pharmacology , Receptors, Muscarinic/physiology , Tubocurarine/analogs & derivatives , Tubocurarine/pharmacology , Vecuronium Bromide/pharmacology
18.
Res Vet Sci ; 36(3): 348-53, 1984 May.
Article in English | MEDLINE | ID: mdl-6463378

ABSTRACT

The non-depolarising muscle relaxants alcuronium (0.1 mg kg-1), gallamine (1 mg kg-1) and pancuronium (0.06 mg kg-1) were administered to six dogs. At 50 per cent return of neuromuscular activity, as measured by the train-of-four technique, the depolarising muscle relaxant suxamethonium (0.3 mg kg-1) was injected intravenously. At 50 per cent return of neuromuscular activity, atropine and neostigmine were administered to reverse the neuromuscular block. The duration of action of suxamethonium was reduced by each of the non-depolarising muscle relaxants.


Subject(s)
Anesthesia/veterinary , Dogs/surgery , Neuromuscular Blocking Agents/pharmacology , Succinylcholine/pharmacology , Alcuronium/pharmacology , Animals , Dogs/physiology , Drug Interactions , Gallamine Triethiodide/pharmacology , Muscles/drug effects , Pancuronium/pharmacology , Preanesthetic Medication , Thiopental
19.
Res Vet Sci ; 32(1): 121-3, 1982 Jan.
Article in English | MEDLINE | ID: mdl-7089375

ABSTRACT

A technique is described for assessing the extent of residual neuromuscular block following non-depolarising agents in the dog. The ulnar nerve was electrically stimulated with a train-of-four impulses and the muscle responses recorded. Heights of the control and, following the administration of the muscle relaxant, the first, second and fourth twitch tensions (T1, T2 and T4) of the train were measured. There was a highly significant linear correlation between the ratio T1/control, used to determine the extent of neuromuscular block, and the other ratios T2/T1 and T4/T1. Both of the ratios T2/T1 and T4/T1 avoid the use of control heights.


Subject(s)
Gallamine Triethiodide/pharmacology , Muscles/drug effects , Neuromuscular Junction/drug effects , Pancuronium/pharmacology , Animals , Dogs , Electric Stimulation , Forelimb , Muscle Contraction/drug effects , Muscles/physiology , Ulnar Nerve/physiology
20.
Res Vet Sci ; 29(3): 277-80, 1980 Nov.
Article in English | MEDLINE | ID: mdl-7255889

ABSTRACT

Evoked muscle responses to train-of-four electrical nerve stimuli were recorded from the nose and foreleg in the intact dog. Low and high doses of both suxamethonium and either pancuronium or gallamine were injected, and the recordings of muscle responses from each dog were examined. Recordings taken from the foreleg showed the presence of train-of-four fade until complete neuromuscular block was established. Simultaneous recordings from the nose showed the development of a train-of-four fade in early stages of neuromuscular block, but as the block increased, an unusual response developed where the twitch height became equal. This finding occurred following suxamethonium as well as non-depolarising relaxants.


Subject(s)
Electric Stimulation/methods , Neuromuscular Junction/physiology , Animals , Dogs , Evoked Potentials , Facial Nerve/physiology , Forelimb/physiology , Gallamine Triethiodide/pharmacology , Muscle Contraction/drug effects , Neuromuscular Junction/drug effects , Nose/physiology , Pancuronium/pharmacology , Succinylcholine/pharmacology , Ulnar Nerve/physiology
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