Maximum Twitch Tension Research Articles

Epitrochlearis muscle. I. Mechanical performance, energetics, and fiber composition.

An in vitro rat muscle preparation is described that can contract at rates of 12-240 twitches/min. Maximum dF/dt paralleled maximum twitch tension, their ratio being constant at approximately 8 ms for contraction rates of 12-120 twitches/min. Time to peak tension was 8-13 ms, time to peak dF/dt 5-8 ms, and half-relaxation time 4 ms. These parameters were unaffected by rate of contraction or duration of isometric work. Differential ATPase staining demonstrated that 60-65% of the fibers were fast-twitch white, 20% fast-twitch red, and 15% slow-twitch red. The preponderance of fast-twitch fibers correlated with the observed mechanical performance of the muscle. Muscles contracting for 60 min at rates up to 48 twitches/min maintained total adenine nucleotide content (ATP, ADP, AMP) at near resting levels. At higher twitch rates (72-240 twitches/min), total adenine nucleotide content decreased 40%, reflecting exclusively a fall in ATP in the presence of adequate phosphocreatine stores. Adequate oxygenation was reflected by lactate-to-pyruvate ratios in the range of 11-15 at all rates of contraction.

Effects of calcium on the sarcomere length-tension relation in rat cardiac muscle. Implications for the Frank-Starling mechanism.

HomeCirculation ResearchVol. 47, No. 4Effects of calcium on the sarcomere length-tension relation in rat cardiac muscle. Implications for the Frank-Starling mechanism. Free AccessAbstractPDF/EPUBAboutView PDFSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyRedditDiggEmail Jump toFree AccessAbstractPDF/EPUBEffects of calcium on the sarcomere length-tension relation in rat cardiac muscle. Implications for the Frank-Starling mechanism. A M Gordon and G H Pollack A M GordonA M Gordon Search for more papers by this author and G H PollackG H Pollack Search for more papers by this author Originally published1 Oct 1980https://doi.org/10.1161/01.RES.47.4.610Circulation Research. 1980;47:610–619 Previous Back to top Next FiguresReferencesRelatedDetailsCited ByHancock W, Martyn D and Huntsman L (1993) Ca2+ and segment length dependence of isometric force kinetics in intact ferret cardiac muscle., Circulation Research, 73:4, (603-611), Online publication date: 1-Oct-1993.Walley K, Ford L and Wood L (1991) Effects of hypoxia and hypercapnia on the force-velocity relation of rabbit myocardium., Circulation Research, 69:6, (1616-1625), Online publication date: 1-Dec-1991.Schouten V, Bucx J, de Tombe P and ter Keurs H (1990) Sarcolemma, sarcoplasmic reticulum, and sarcomeres as limiting factors in force production in rat heart., Circulation Research, 67:4, (913-922), Online publication date: 1-Oct-1990.Gupta K, Bavaria J, Ratcliffe M, Edmunds L and Bogen D (1989) Measurement of end-systolic pressure-volume relations by intra-aortic balloon occlusion., Circulation, 80:4, (1016-1028), Online publication date: 1-Oct-1989.Urthaler F, Walker A, Reeves D and Hefner L (1988) Maximal twitch tension in intact length-clamped ferret papillary muscles evoked by modified postextrasystolic potentiation., Circulation Research, 62:1, (65-74), Online publication date: 1-Jan-1988.Lew W (1988) Time-dependent increase in left ventricular contractility following acute volume loading in the dog., Circulation Research, 63:3, (635-647), Online publication date: 1-Sep-1988.de Beer E, Schiereck P and van Kaam F (1986) Real-time kinetics of sarcomere relaxation by laser diffraction., Circulation Research, 58:6, (896-897), Online publication date: 1-Jun-1986.Pollack G (1986) Quantal mechanisms in cardiac contraction., Circulation Research, 59:1, (1-8), Online publication date: 1-Jul-1986.Lecarpentier Y, Martin J, Claes V, Chambaret J, Migus A, Antonetti A and Hatt P (1985) Real-time kinetics of sarcomere relaxation by laser diffraction., Circulation Research, 56:3, (331-339), Online publication date: 1-Mar-1985.Tucci P, Bregagnollo E, Spadaro J, Cicogna A and Ribeiro M (1984) Length dependence of activation studied in the isovolumic blood-perfused dog heart., Circulation Research, 55:1, (59-66), Online publication date: 1-Jul-1984. October 1, 1980Vol 47, Issue 4Article InformationMetrics Download: 250 Copyright © 1980 by American Heart Associationhttps://doi.org/10.1161/01.RES.47.4.610 Originally publishedOctober 1, 1980 PDF download

Liposomes. Effect of temperature on their mode of action on single frog skeletal muscle fibers

Liposomes containing the fluorescent dye 6-carboxyfluorescein were made from dipalmitoyl phosphatidylcholine and stearylamine. At 4°C the liposomes are adsorbed on the fiber surface and when the temperature is raised to 21°C, their contents are transferred directly into the fibers at a linear rate. Liposomes had little effect on the time course of the maximal twitch tension.

The effects of acute and chronic ethanol administration on twitch and tetanic force production by rat gastrocnemius muscle in situ.

The effects of acute ethanol injection on force production were measured in normal and chronic alcoholic rats. Acutely injected normal rats, acutely injected chronic alcoholic rats, and noninjected chronic alcoholic rats were compared with control groups: normal nonalcoholic rats and a dietetically deprived control group. Acute ethanol injection increased twitch force in normal rats but not in chronic alcoholic rats. Chronic alcohol ingestion caused a decrease in maximal twitch and tetanic tension. The dietetically deprived control group developed less maximal tetanic force, with no significant decrease in maximal twitch force. Chronic alcohol ingestion seemed to decrease maximal twitch tension, whereas the decrease in maximal tetanic could be attributed to the effects of malnutrition.

Effects of paraplegia produced by intrathecal 6-aminonicotinamide on motor units in the rat

An intrathecal injection of 6-aminonicotinamide (6-AN) in adult rats produced a central myelopathy with destruction of neurons and gliosis. After a latent period of 24 to 36 h, the animals developed flaccid paralysis of the hind limbs, followed by irreversible hypertonic paraplegia. Motor nerve conduction velocities in the tibial nerve of 6-AN-treated animals (serial recordings 3–550 days) were the same as controls and teased nerve fibers to extensor digitorum longus (EDL) and soleus muscles showed no evidence of nerve regeneration. In vivo studies of contractile properties of 6-AN-treated soleus showed that the mean maximal twitch and tetanic tensions were greatly reduced compared to controls by 14 days. The same occurred in the 6-AN-treated EDL, but to a lesser degree. These changes in contractile properties persisted throughout the 570-day period of observation. There was no significant change in the percentage of fiber types in the soleus muscles after 6-AN. However, the EDL had an increased number of type I fibers by 30 days and this peaked at 90 days and was associated with a decrease in type IIC and IIA but not IIB fibers. Initially the type I fibers occurred at random, but by 2 to 3 months, they occurred in small groups of 5 to 20 fibers. The mean areas of all fibers were reduced as early as 2 weeks in both 6-AN-treated EDL and soleus muscles. These changes most likely resulted from the chronic hypertonic paraplegia with extensor posturing, followed by immobilization at knee and ankle joints and loss of some spinal motoneurons with peripheral sprouting, especially of type I motoneurons.

Pharmacological properties of kryptopyrrole and its oxidation products on isolated sciatic nerve of rat and on guinea-pig ileum.

1 Kryptopyrrole (2, 4-dimethyl, 3-ethylpyrrole) inhibited conduction in rat sciatic nerve by a local anaesthetic action. 2 Tone and both spontaneous and electrically-induced contractions of guinea-pig ileum were also inhibited by kryptopyrrole. The concentration of kryptopyrrole required for 50% inhibition of a maximum twitch tension (ID50) was 0.085 mM. 3 Oxidation products of kryptopyrrole with chromatographic properties similar to those of urinary constituents reported in schizophrenia and hepatic porphyrias had little or no effect at similar concentrations. 4 Dose-response curves to exogenous acetylcholine in guinea-pig ileum were shifted to the right by kryptopyrrole, with loss of parallelism and reduction in the maximum contraction. 5 Acetylcholine overflow from ileal segments at rest and during electrical stimulation was reduced by kryptopyrrole. 6 These results on ileal segments are consistent with kryptopyrrole having both a post-junctional site of action, presumably directly on the muscle, and a pre-junctional site reducing the output of acetylcholine from the myenteric plexus. 7 The significance of these findings is discussed in relation to a possible clinical pathological role for these compounds.

Evidence for the maintenance of motoneurone properties by msucel activity.

1. Electrophysiological properties of soleus motoneurones in adult cats were examined with intracellular electrodes following alterations of activity of the soleus muscle induced by transection of the thoracic spinal cord or by conduction block of the muscle nerve with tetrodotoxin (TTX) cuffs. Attempts were also made to maintain muscle activity by daily stimulation of the maintain muscle activity by daily stimulation of the peripheral nerve. 2. Within 8 days after transection of the thoracic cord, soleus motoneurones showed a significant decrease in the duration of afterhyperpolarization following action potentials. This change in motoneurone properties induced by cord transection was prevented by daily stimulation of the sciatic nerve. 3. Soleus motoneurones showed a significant decrease in the duration of after-hyperpolarization within 8 days after conduction block of the soleus nerve with TTX. This change in montoneurone properties was prevented by daily stimulation of the nerve peripheral to the TTX cuff but not central to the cuff. 4. The soleus muscle showed a significant decrease in weight relative to body weight within 8 days after transection of the thoracic cord. This decrease in muscle weight following cord transection was prevented by daily stimulation of the sciatic nerve. 5. No fibrillation was detected in the soleus muscle 8 days after conduction block of the soleus nerve with TTX. The maximum twitch tension of the soleus muscle evoked by nerve stimulation showed no significant difference between the two sides treated and untreated with TTX. Fast axoplasmic transport measured with cholinesterase as a marker was not affected by TTX. Thus, there was no sign of functional although morphological abnormalities were found in some nerve fibres. 6. It is concluded that motoneurone properties in an adult depend partly upon some factors associated with activity of the innervated muscles and that such trophic signals are retrogradely carried by the motor axons.

Muscular dystrophy in mice after chronic subcutaneous treatment with cannabinoids

Swiss male albino mice were treated subcutaneously with the main cannabinoids (CBN, CBD, Δ 9-THC) at the dosage of 1 mg/kg per day for 30 days, and with the crude resin. At the end of the treatment, after supramaximal stimulation of the sciatic nerve, a significant decrease of both maximal twitch and tetanus tensions was observed in Δ 9-THC-treated animals; CBD and resin treatment produced some decrease in active tension, while CBN treatment induced an enhancement of the contractile strength. Histology showed lesions interpretable as due to muscular dystrophy. Analysis of protein and hydroxyproline muscular content showed a marked reduction in protein in all treated animals, with a corresponding high increase in hydroxyproline content.

Oxygen sufficiency in working rabbit papillary muscle at 25°C

The mechanical and metabolic responses of isometrically contracting rabbit papillary muscle were studied as a function of cross-sectional area to determine whether a hypoxic core developed with increasing frequency of stimulation ( v ). Papillary muscles ( n =21) were divided by cross-sectional area ( A ) into three sets: I A 2 ; II 0.4 A 2 and III A >0.8 mm 2 . The stimulation frequency was varied from 0.025 Hz to 0.8 Hz. The mechanical response was measured by the maximum twitch tension, maximum time derivative of the tension and the time to peak tension. Although there were differences in the ratios of the mechanical response between the three sets of muscles, the differences were not frequency dependent. The metabolic response was measured by monitoring the maximum change in intramitochondrial NADH fluorescence resulting from contractile activity. The differences in metabolic response between the three sets of muscles were similar to those evident with the mechanical parameters and were also frequency independent. Since differences in mechanical and metabolic response between the three sets of muscles were frequency independent, it is unlikely that a hypoxic core develops in rabbit papillary muscle with A 2 , v T =25°C.

A study of functional denervation in fast and slow muscles of dystrophic mice of various ages

It has been claimed that some fibers in dystrophic mouse muscle are denervated and, furthermore, that there is no increase in motor unit size which would be expected to occur if reinnervation took place. If these observations are correct, it ought to be possible to demonstrate a mechanical correlate of the denervation phenomenon. The functional innervation ratio (ratio of maximum twitch tension in response to nerve stimulation × 100 to maximum twitch tension in response to direct muscle stimulation) has been determined for the extensor digitorum longus and soleus muscles of normal ( C57B1 6J ) and dystrophic ( dy 2J dy 2J ) mice of various ages. It is shown that although a fall in the functional innervation ratio is seen in both muscles, it occurs some time after the symptoms of the disease are apparent. This suggests that denervation may not be the primary event in murine muscular dystrophy. The fall in functional innervation ratio is apparently not due to an enhanced susceptibility of the dystrophic neuromuscular junction to anoxia, because dystrophic muscles showed the same response to a raised bath temperature as did normal muscles.

The twitch-contraction characteristics of opossum jaw musculature

The characteristics of twitch contractions in the masticatory muscles of the American opossum were investigated in situ. The mean time to peak contraction in Temporalis was 18.3 msec, in Masseter—15.8 msec, in Medial Pterygoid—15.9 msec and in Anterior Digastric-11.1 msec. The length-tension relationship (length expressed as a jaw position) was highly characteristic for each elevator muscle. The maximum twitch tension was produced at different jaw positions in each case: Temporalis at 33 ° open, Masseter at 29 ° and Medial Pterygoid at 20 ° open. Hysteresis was present, however, in the length-tension relationship.

Contractile properties of muscle undergoing "compensatory" hypertrophy and its increased susceptibility to denervation and reflex atrophy.

The contraction properties of the soleus muscle undergoing “compensatory” hypertrophy were studiedin situ in 120–150 g male rats 7 and 85 days after tenotomy of synergistic muscles. The time to peak of isometric twitch contractions in seven-day hypertrophy is somewhat prolonged, while the twitch tension is diminished as compared with control muscles of rats of corresponding weight and age. Maximum twitch tension of muscles hypertrophied by 26% is significantly reduced by 29% when calculated per gram dry muscle weight. Tetanic tension, on the other hand, was 13% higher in the hypertrophied muscles, but still lower when calculated per gram dry muscle weight. Eighty-five days after tenotomy of synergists, when there is still 15% hypertrophy of the soleus, there was a tendency of the various contraction paramaters to become normalized. The newly formed muscle mass during “compensatory” muscle hypertrophy is highly susceptible to the catabolic effects of denervation, or nociceptive stimulation. Superimposition of denervation or reflex atrophy (induced by fracture of metatarsal bones of the paw and turpentine oil injection) upon three-day hypertrophy led to a dramatic loss of weight. After four-day denervation, the soleus lost 42.7% in weight, the plantaris 28.0% and the extensor digitorum longus 24.4%. The corresponding values in the case of reflex atrophy were 26.5%, 25.5% and 17.7% respectively.

Muscle strength in boys of different ages.

Isometric twitch contractions have been studied in extensor hallucis brevis muscles of 32 healthy male subjects aged between 3 and 25 years. The maximum twitch tensions were found to increase gradually with age and then to undergo marked enhancement at puberty. After puberty little further change occurred. In the youngest children examined the twitch contraction times were already within the adult range, though the half-relaxation times were prolonged.

Contractile properties of skeletal muscle from trained miniature pig.

The isometric contractile properties of thetibialis anterior muscle were measuredin situ in male miniature pigs. The pigs were divided into three groups at 2 mouths of age; one group trained by endurance running, the second group trained by sprint running and the third group served as an unexercised control. After 7 months of training, the endurance group ran continuously for 60 min at 95 m/min and a 5% slope and the sprint group ran ten 60 sec sprints at 198 m/min and a 10% slope, each sprint interspersed with a 1 min rest interval. The mean values for contraction time, one-half relaxation time, twitch tension, tetanus tension and twitch-tetanus ratio were not significantly different (P>0.05) among the three groups. Fatigability was measured by stimulating the muscle preparation for 45 min at a frequency of 4 impulses/sec. Both trained groups maintained a significantly higher (P<0.05) percentage of their maximal twitch tension than the control group over the 45 min period. These results support previous research which suggest that isometric contractile properties of whole, heterogeneous muscle resist change after chronic, physiological exercise programs. However, both types of training produced increased skeletal muscle endurance.

Overloaded skeletal muscles of a nonhuman primate ( Galago senegalensis)

Selected morphological, biochemical, and physiological properties of skeletal muscles from five control and six trained adult nonhuman primates, Galago senegalensis, were studied. After a 6-month treadmill endurance-training program, fewer glycogen-depleted fibers were found in the plantaris of trained than in controls after 15 min of electrical stimulation. There was an increase in the proportion of fast-twitch oxidative-glycolytic fibers at the expense of fast-twitch glycolytic fibers, enhanced cytochrome a and c concentrations, and elevated SDH activity. No changes in glycolytic enzymes or contraction time of the normally fast-twitch plantaris muscle were found. Maximal twitch and tetanic muscle tension and overall fiber size were not significantly different in the controls and trained Galagos. However, fast-twitch oxidative-glycolytic fibers in the plantaris were significantly larger in the trained Galagos. These adaptations were muscle specific, demonstrating that muscles vary in response to treadmill exercise depending on anatomical location or action (or both) in the exercise as well as fiber-type composition.

A comparison of isometric contractions of the whole muscle with those of motor units in a fast-twitch muscle of the cat

Isometric twitches and tetani of motor units and of the whole muscle were observed at various muscle lengths in a fast-twitch muscle of the cat. Some of the motor units developed maximum twitch and tetanic tensions at similar muscle lengths which were close to the optimum lengths for whole muscle contractions, but for others the optimum for the twitch was much longer than that for the tetanus. Contrary to earlier reports the anomalous behavior of this second group of units was not related to the size of the motor unit, nor was it due to neuromuscular failure. Mechanical latencies were not prolonged below the motor unit twitch optimum. Nonlinear summation of single motor unit twitches with those of larger groups of muscle fibers was sometimes found. There was a deficit of one third in the summed twitches of all the motor units but little distortion of contraction times.

Effects of PCO2, bicarbonate and lactate on the isometric contractions of isolated soleus muscle of the rat.

Isometric contractions of isolated soleus muscles of 3 weeks old rats show a potentiation of the maximal twitch tension when theP CO2 is increased, or when the [HCO 3 − ] is increased with a reciprocal decrease in [Cl−]. The reverse response is observed on decrease of theP CO2 and on decrease of the [HCO 3 − ] with a reciprocal increase in [Cl−]. The addition of lactate ions results in a potentiation of the maximal twitch, whether accompanied by a reciprocal decrease in [HCO 3 − ] or in [Cl−]. The maximal tetanic tension is augmented by rising theP CO2, by increasing the [HCO 3 − ] with simultaneous lowering of [Cl−], or by the addition of lactate ions.

Neuromuscular function at low temperatures in frogs from cold and warm climates

1. 1. Nerve-muscle function was studied at a variety of temperatures in the most northerly American frog, Rana sylvatica, and in a southern (west-central Mexico) population of Rana pipiens. 2. 2. Maximal twitch tension in isolated gastrocnemius muscles increased with decreasing temperature in R. sylvatica but decreased with decreasing temperature in R. pipiens. 3. 3. R. sylvatica muscles excitable to sciatic nerve stimulation until the freezing point (−3 to −5°C) was reached. Muscles from R. pipiens became inexcitable to either nerve or direct stimulation at about 0°C. 4. 4. No temperature-related differences in nerve function were seen between the two species.

Thermal adjustments in cardiac and skeletal muscles of lizards

1. Isometric twitch tension development was measured over a wide range of temperatures in skeletal and cardiac (ventricular) muscles from diverse Australian lizards representing several families and including both diurnal and nocturnal species. 2. The temperatures at which maximal twitch tension develops (optimal temperatures) in the skeletal muscles is higher, by about 10–15° C, than in the ventricular muscles from the same species. Resistance to heat damage (thermostability) is similar for the two tissues. 3. Interspecific divergence is evident in the optimal temperatures and thermostabilities of both muscles, and these tissue differences parallel the preferred body temperatures of the species from which they are taken. In several nocturnal lizards (geckos) that have high preferred body temperatures, the thermal adjustments of the muscles resemble those of diurnal species, whereas muscles from geckos with low preferenda have relatively low optimal temperatures. 4. Variations in the heat resistance of the tissues correlate with variations in organismal heat resistance and in general, lethal temperatures for excised muscles and organism are similar. 5. These data are interpreted as indicating that divergence in the thermal adjustments for contractility of muscular tissues are most directly associated with the temperatures characteristically maintained through the behavior of the species rather than to the general geographical (climatic) distribution or phylogenetic position of the species.

Combined effects of nitrate and caffeine on contractions of skeletal muscles

Joint action of 1 mm caffeine and NO3– after exposure to NO3– alone did not increase tension output of excised, curarized gastrocnemius muscles of healthy mice beyond NO3– values. In dystrophic mouse muscles, twitch tension increased further and 1.5 times as much as in 1 mm caffeine alone. In both muscles caffeine pretreatment permitted NO3– further to enhance twitch tension as though it were acting alone. Caffeine enhancement of tetanus tension disappeared in normal and rose further in dystrophic muscles. In both muscles jointly evoked maximal twitch tensions were the same regardless of pretreatment. Neither agent alone could duplicate jointly elicited tension increases. In excised, curarized frog sartorius muscles jointly produced twitch tensions after NO3– pretreatment were the sum of individual NO3– and caffeine enhancements. Caffeine pretreatment reduced the subsequent NO3– alone. These results suggest defects in NO3–-susceptible Ca++ sites of dystrophic membranes, and greater sensitivity to caffeine-induced Ca++ mobility in frog than in mouse muscles.