Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Muscle Relaxation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed1980

Inotropic effects of non-depolarizing muscle relaxants in isolated canine heart muscle.

The inotropic effects of five non-depolarizing muscle relaxants were examined using an isolated canine heart muscle preparation. Except for fazadinium, all drugs were studied in their commercially available forms. d-Tubocurarine chloride (dTc) and metocurine iodide (MTC) produced dose-dependent decreases in isometric force (F) and the maximum velocity of force development (dF/dt) at concentrations greater than 22.5 x 10(-3) g/L for dTc and greater than 15.0 x 10(-3) g/L for MTC, concentrations which are 3 and 6 times higher than estimated clinical serum concentrations, respectively. Myocardial depression was about 3 times less with MTC than with dTc at equipotent concentrations. The degree of depression in F and dF/dt produced by MTC was almost identical with that produced by phenol, a preservative of MTC, indicating that MTC-induced myocardial depression may be due to the effect of the preservative. Pancuronium bromide (PC) produced a dose-dependent increase in F and dF/dt and decrease in the time to peak force. PC-induced changes in F, dF/dt, and time to peak force were inhibited by administration of propranolol 10(-6) M. The results indicate that PC possesses a positive inotropic effect mediated by beta-adrenergic stimulation. Alcuronium chloride did not change F or dF/dt at concentrations from 5.0 x 10(-3) to 60.0 x 10(-3) g/L. Frazadinium bromide increased F and dF/ dt slightly at a low concentration (1.875 x 10(-2) g/L), but further increases in its concentration returned the values of F and dF/dt to control levels. F and dF/dt were not altered in vitro by concentrations of relaxants that would be anticipated in plasma in vivo in patients given clinically effective doses of 0.3 mg/kg of dTc, 0.1 mg/kg of MTC or PC, 0.2 mg/kg of alcuronium chloride, or 0.75 mg/kg of fazadinium bromide.

Alcuronium↗
PubMed1987

[Reproducibility of intradermal tests after anaphylaxis caused by muscle relaxants].

Intradermal tests with 5 muscle relaxants were performed on two occasions in 56 patients who had experienced an adverse event during general anaesthesia: anaphylactoid reaction with at least one positive test 19.5 +/- 13.5 months previously in 50 cases; adverse reaction unrelated to muscle relaxants and with negative tests 21 +/- 6.4 months previously in 6 cases. Sixteen healthy subjects who had never been tested served as controls; their tests were all negative. The reproducibility of 244 assessable tests in the 56 patients reached 88.1%. Twenty-three (9.4%) of the tests previously positive had become negative and six (2.5%) of the tests previously negative had become positive. Tests performed with pancuronium or vecuronium had more often become negative (47% and 40% respectively) than those performed with the other 3 muscle relaxants tested (P less than 0.001). These results suggest that skin tests should be repeated prior to general anaesthesia in all patients who previously developed an anaphylactoid reaction to muscle relaxants.

Adult↗
PubMed1981

[Effects of muscle relaxant E.M.P.P. on afferent discharges of muscle spindle in man--an microneurographic analysis (author's transl)].

Effects of a new muscle relaxant E.M.P.P.(4'-ethyl-2-methyl-3-piperidino-propiophenone . hydrochloride) on afferent discharges of muscle spindle were studied in 10 healthy volunteer subjects. Single unit afferent discharges of muscle spindle were recorded microneurographically from the median or tibial nerve using a tungsten microelectrode with a tip diameter of about 1 micrometer (impedence: about 10 M omega). Effects of an oral administration of 150--300 mg of E.M.P.P. on spontaneous afferent discharges as well as dynamic and static responses of muscle spindle were analysed in the present study. 1. E.M.P.P. suppressed remarkably the frequency of spontaneous afferent discharges of muscle spindle. Meanwhile, mental activations such as speech of mental arithmetic recovered temporarily the frequency of afferent discharges to that before E.M.P.P. administration. 2. E.M.P.P. suppressed the dynamic and static responses of muscle spindle to stretch. It also suppressed the dynamic responses of muscle spindle in the decontraction phase of electrically-induced twitch contractions of the receptor-bearing muscle. Based on these results, it is concluded that E.M.P.P. suppresses the static and dynamic activities of muscle spindle in man. These effects seem to be due to modifications of descending influences from central structures on the static and dynamic gamma motoneurons which innervate the muscle spindle.

Adult↗
PubMed1984

The pull-up test in rats: a simple method for evaluating muscle relaxation.

A test for muscle relaxation in rats is described. The pull-up test is performed by holding an inverted rat by its hind legs. The time taken by the rat to pull itself up and grasp the hand of the experimenter is used as the test parameter. It is simple and quick and separates muscle relaxation from sedation, catalepsy, and catatonia.

Animals↗
PubMed1996

Muscle relaxants: a clinical update.

The new nondepolarizing muscle relaxant rocuronium belongs to the chemical group of aminosteroidal muscle relaxants and is similar to vecuronium in its chemical structure and pharmacologic action. The principal clinical advantage of rocuronium over vecuronium is the short time to onset of the neuromuscular block. The two other new muscle relaxants, mivacurium and cis-atracurium, belong to the group of benzylisoquinoline muscle relaxants. Mivacurium is rapidly degraded in plasma and its principal characteristic is, hence, a short duration of action. Cis-atracurium is one of the 10 stereoisomers of atracurium. While its action is similar to that of atracurium, it does not release histamine and its administration is not accompanied by marked changes in blood pressure or heart rate. Even the simple tactile monitoring of the neuromuscular transmission enables the clinician to adjust the doses of these and other muscle relaxants to the needs of individual patients. Precise adjustment of the doses of muscle relaxants contributes to their safer clinical use by avoiding an excessively deep and unnecessarily prolonged neuromuscular block.

Androstanols↗
PubMed1996

Variation of serum potassium and creatinine phosphokinase levels in suxamethonium-induced muscle relaxation.

Popular depolarising muscle relaxant, suxamethonium (succinylcholine chloride), produces fasciculation in group of muscles and 'after pain'. Mode of its action is neuromuscular blockage. It also may be associated with muscle fibre injury and altered membrane permeability. These may cause rise of serum K+ and creatinine phosphokinase (CPK) levels. But use of diazepam either during or as pretreatment may reduce the fasciculation, 'after pain' and rise of K+ and CPK levels. Present study was undertaken to show whether any correlation of the degree of fasciculation and postsuxamethonium myalgia is present or not and whether diazepam has any role in reducing muscle injury and in turn reducing the levels of serum K+ and CPK.

Adult↗
PubMed1994

[Modern muscle relaxants and their clinical application].

Various new muscle relaxants are available: atracurium, rocuronium and vecuronium all have an intermediate duration of action, whereas doxacurium and pipecuronium are long-acting and mivacurium is a short-acting nondepolarizing muscle relaxant. The duration of action of atracurium and mivacurium is determined by their degradation, which makes them unique among the nondepolarizing muscle relaxants in this respect. The time of onset is shortest with rocuronium, while vecuronium is probably the muscle relaxant with the fewest undesirable side-effects. In clinical practice, muscle relaxants of short and intermediate duration of action should be preferred, since such agents carry the least risk of residual neuromuscular block postoperatively. Because recovery from them is slow, long-acting agents should preferentially be used only when postoperative mechanical ventilation is intended. The use of a peripheral nerve stimulator is the only reliable guide to appropriate administration of muscle relaxants.

Humans↗
PubMedDate not supplied

Some actions of chandonium iodide, a new short-acting muscle relaxant, in anaesthetized cats and on isolated muscle preparations.

1. The actions of the new skeletal muscle relaxant chandonium (HS310) on the cardiovascular, respiratory and skeletal muscle systems of the cat under chloralose anaesthesia and on chick and rat isolated skeletal muscle preparations have been described. 2. In the cat chandonium exhibited a potent, competitive, non-depolarizing neuromuscular blocking action that was rapid in onset and of short duration. It possessed a selective atropine-like action at the cardiac vagus neuro-effector junction but little or no ganglion blocking activity. Neither adrenergic neurone noralpha-adrenoceptor blocking properties were evident. 3. Unlike tubocurarine, chandonium was without effect on the airways system of the anaesthetized cat. 4. Chandonium possessed weak anticholinesterase action. It is conceivable that this effect may contribute to its short duration of action. 5. The results from these studies suggest that chandonium may have possible clinical applications as a short-acting muscle relaxant.

Acetylcholine↗
PubMed1995

Characterization of ciliary muscle relaxation induced by various agents in cats.

PURPOSE: To understand the cellular mechanism underlying the relaxation of ciliary muscle, relaxation induced by prostaglandins (PGs) and some other agents was characterized in the cat. METHODS: Tone of isolated ciliary muscle was measured by means of a force-displacement transducer. Adenylate cyclase activity was determined with membrane fraction of ciliary muscle by measuring the formation of cyclic adenosine monophosphate (cAMP). RESULTS: The addition of various PGs and isoproterenol relaxed the ciliary muscle that had been precontracted with 3 x 10(-6) M carbachol. The relaxation was dose dependent, with an EC50 of 2 x 10(-7) M for PGE2. The rank order of potency by which PGs induced relaxation (PGE2 = E1 > D2 > F2 alpha > I2) was identical with that reported for EP type prostaglandin receptor-mediated responses except for PGD2, which was more potent than expected. Agents that increased cellular cAMP, such as forskolin and IBMX, also relaxed the precontracted muscle. Nitric oxide donors, such as sodium nitroprusside and S-nitroso-N-acetyl-DL-penicillamine (SNAP), also caused dose-dependent relaxation. PGs and isoproterenol, but not nitroprusside, stimulated adenylate cyclase. The rank order of potency by which PGs stimulate adenylate cyclase was similar to that observed for muscle relaxation, suggesting that cAMP is the cellular second messenger for the PG-induced muscle relaxation and thus that PG receptors of EP2 and DP type are involved. CONCLUSIONS: Relaxation of cat ciliary muscle is mediated by two independent mechanisms: a cAMP-dependent one, which includes beta-adrenergic, EP2, and DP receptor-mediated responses, and a cAMP-independent one, which includes the nitric oxide-induced mechanism.

Adenylyl Cyclases↗
PubMed2003

Muscle relaxants.

Studies on the toxic effects of muscle relaxants are difficult to design because of the need for mechanical ventilation and, consequently, concomitant administration of anaesthetic drugs which may influence the results. The following overview shows that muscle relaxants are weak toxic agents with regard to their teratogenicity, carcinogenicity and cytotoxic effects (including tissue- and organ-damaging effects). Moreover, this chapter presents other side-effects of muscle relaxants under the broad heading of toxicity: the succinylcholine-triggered cytotoxic effects on skeletal muscle cells with different aetiology, for example, or persistent muscle weakness after long-term administration of non-depolarizing muscle relaxants. Receptor stimulation in the central nervous system may cause acute excitement and seizures. Muscle relaxants and their metabolites may interact with muscarinic and nicotinic receptors in other organs and the ganglionic system, for example in the cardiovascular system. Direct stimulation of mast cells, with consequent release of histamine, after administration of muscle relaxants may clinically impose as toxic reactions.

Abnormalities, Drug-Induced↗
PubMed1992

[Effects of magnesium and calcium on muscle contractility and neuromuscular blockade produced by muscle relaxants and aminoglycoside].

The muscle contractility and neuromuscular blockade of muscle relaxants are influenced by the electrolytes, especially magnesium ion(Mg2+) and calcium ion(Ca2+), in the extracellular fluid. The present study was designed to evaluate the effects of Mg2+ and Ca2+ on muscle contractility and on the blocking properties of d-tubocurarine, succinylcholine and aminoglycoside antibiotics, tobramycin in vitro, using rats' phrenic nerve-hemidiaphragm preparations. Mg2+ inhibited the twitch tensions in a concentration dependent manner. A low concentration of Ca2+ decreased the twitch tensions, but a high concentration of Ca2+ had no effect on them. Mg2+ potentiated the block produced by d-tubocurarine, succinylcholine and tobramycin depending on the concentration of Mg2+, and good regression lines were obtained. Ca2+, however, antagonized the neuromuscular blockade of the three drugs at any level of Mg2+ concentration. From these findings, it should be noticed that special care must be taken to prevent a profound neuromuscular blockade due to the drug interaction of each drug when a muscle relaxant or an aminoglycoside antibiotics is administered to a patient suffering from hypermagnesemia and/or hypocalcemia.

Aminoglycosides↗
PubMed1975

Antiphosphodiesterase activity and nonspecific smooth muscle relaxation tested on intestinal smooth muscles.

Mitochondrial, microsomal and soluble fractions separated from the guinea pig taenia and from the dog longitudinal smooth muscle were used as phosphodiesterase preparation. Each preparation had low and high Km values, indicating the existence of at least two kinds of phosphodiesterase. Papaverine and Aspaminol (1, 1-diphenyl-3-piperidinobutanol hydrochloride), hydralazine, caffeine Na benzoate and aminophylline were used at test drugs. Aspaminol had little inhibitory effect on phosphodiesterase. Ki value of papaverine almost equalled the concentration (M) which was necessary to produce 50% relaxation. Relaxation of the guinea pig taenia by papaverine was preceded by an increase of intracellular cyclic AMP,. Therefore, the action of papaverine is likely to be mediated by an increase in cyclic AMP, which is caused by inhibition of the phosphodiesterase-catalyzed breakdown of cyclic AMP. There was little correlation between relaxing activities of the drugs used and their antiphosphodiesterase activities. Relaxation of the smooth muscle induced by the smooth muscle relaxants excepting papaverine is not due to inhibition of phosphodiesterase.

Animals↗
PubMed1981

Inhibition of Ca-movement and mechanical movement in rabbit taenia coli by a smooth muscle relaxant (suloctidil).

A smooth muscle relaxant (suloctidil) relaxed a contractile response of taenia coli to acetylcholine and noncompetitively depressed a dose response curve of Cacl2 Ca-uptake by the microsomal fraction was inhibited by suloctidil. Its noncompetitive antiacetylcholine activity and inhibitory action on Ca-uptake were not influenced by an increase of external Ca-concentration. Ca-release from the Ca-incorporated microsomal fraction was not significantly influenced by suloctidil. These results suggest that suloctidil inhibit Ca-influx noncompetitively, thus inducing smooth muscle relaxation.

Animals↗