Force-velocity characteristics of respiratory airway smooth muscle

Stephens, N. L.; Kroeger, E A; Mehta, Janak A.

doi:10.1152/jappl.1969.26.6.685

Cited by 106 publications

(52 citation statements)

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“…The present direct measurement method overcomes these problems and makes it possible to obtain more directly the force-velocity relationship of muscle. In the present study, we found that in vivo trachealis muscle 10 sec after vagal stimulation exhibited a hyperbolic force-velocity relationship generally similar to that obtained in in vitro measurement of trachealis muscle (Stephens et al 1969;Antonissen et al 1979) and in other smooth muscles (Hellstrand et al 1972).…”

Section: Vagal Stimulation Wassupporting

confidence: 88%

“…On the other hand, the developed force of the trachealis muscle in vitro under isometric conditions reached its peak in around 8 sec (Stephens and Kromer 1971). The present forces developed by vagal stimulation were lower than those by electrical field stimulations (Stephens et al 1969 ;Antonissen et al 1979 ;Sasaki et al 1986). The faster rate and higher values of force development under isometric conditions in vitro than in vivo could be due to different method of vagal stimulation resulting in different amount of actomyosin-ATPase activity.…”

Section: Vagal Stimulation Wasmentioning

confidence: 69%

“…to obtain the force per cross sectional area, which was calculated from the muscle weight, tracheal segmental length and muscle length (lo) with the assumption of a specific gravity of the muscle of 1.05 g/cm3 (Stephens et al 1969). to was measured along the curvature of tracheal ring and about 30% of to was loosely connected to the tracheal cartilage.…”

Section: Trachealis Muscle Shorteningmentioning

confidence: 99%

“…During dynamic respiratory maneuvers, the time course of airway caliber is determined by the balance of timing of passively length-cycled airway smooth muscle and shortening velocity of the contracted airway smooth muscle (Sasaki and Hoppin 1979). Stephens et al (1969) and Antonissen et al (1979) studied the shortening velocity of airway smooth muscle using excised trachealis muscle strips under electrical field stimulation and found that the force-velocity relationship was hyperbolic and could be described by Hill's equation (Hill 1938). They reported that the shortening velocity of the trachealis muscle was slower than that of the striated muscles and suggested that the trachealis muscle could not play a significant role in rapid adjustment of transmural forces transmitted to the airway by the considerably faster striated respiratory muscles.…”

mentioning

confidence: 99%

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Effect of duration of vagal stimulation on shortening velocity of in vivo canine trachealis muscle.

Okayama

Ishii

et al. 1989

Tohoku J. Exp. Med.

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We studied shortening velocity of in vivo canine trachealis muscle contracted by bilateral vagus nerve stimulation, as a function of duration of contraction. The cervical trachea was transected at two locations, cut at the ventral portion, and opened. One side of the cartilage cut was connected to a force transducer and the other to a lever with a given weight as an afterload, the length of which was measured by a linear displacement transducer. Bilateral vagosympathetic trunks were stimulated by supramaximal electrical impulses. With vagal stimulation, the trachealis muscle started to contract isometrically and at a given time the muscle was allowed to contract isotonically by unlocking a stopper at a given afterload. The shortening velocity was reduced with longer duration of active state. Ten sec after vagal stimulation the maximum force was 730+105 g/cm2 (mean ±s.D.) and maximum velocity at zero load calculated by Hill's equation was 0.092 to /sec. We conclude that the force-velocity relationship of in vivo canine trachealis muscle stimulated by vagus nerves exhibits a time-dependency similar to that in vitro. airway mechanics ; airway smooth muscle ; isotonic contraction ; vagal stimulation Constriction of airway smooth muscle controls total and local ventilation by changing airway resistances. During dynamic respiratory maneuvers, the time course of airway caliber is determined by the balance of timing of passively length-cycled airway smooth muscle and shortening velocity of the contracted airway smooth muscle (Sasaki and Hoppin 1979). Stephens et al. (1969) and Antonissen et al. (1979) studied the shortening velocity of airway smooth muscle using excised trachealis muscle strips under electrical field stimulation and found that the force-velocity relationship was hyperbolic and could be described by Hill's equation (Hill 1938). They reported that the shortening velocity of the

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Section: Vagal Stimulation Wassupporting

confidence: 88%

Section: Vagal Stimulation Wasmentioning

confidence: 69%

Section: Trachealis Muscle Shorteningmentioning

confidence: 99%

mentioning

confidence: 99%

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Effect of duration of vagal stimulation on shortening velocity of in vivo canine trachealis muscle.

Okayama

Ishii

et al. 1989

Tohoku J. Exp. Med.

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“…As predicted by Huxley's 1957 model (22), the actomyosin cross-bridge interaction should result in a load-dependent shortening velocity that can be described by a hyperbolic function. Such a hyperbolic relationship between load and shortening velocity has been demonstrated in isolated single cells (43) and cell bundles (17,39) of smooth muscle. It appears therefore that there is strong evidence for actomyosin interaction as the molecular mechanism in smooth muscle contraction, as in striated muscle.…”

mentioning

confidence: 78%

Time course of isotonic shortening and the underlying contraction mechanism in airway smooth muscle

Syyong

Raqeeb

Paré

et al. 2011

Journal of Applied Physiology

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Syyong HT, Raqeeb A, Paré PD, Seow CY. Time course of isotonic shortening and the underlying contraction mechanism in airway smooth muscle. J Appl Physiol 111: 642-656, 2011. First published June 2, 2011; doi:10.1152/japplphysiol.00085.2011.-Although the structure of the contractile unit in smooth muscle is poorly understood, some of the mechanical properties of the muscle suggest that a sliding-filament mechanism, similar to that in striated muscle, is also operative in smooth muscle. To test the applicability of this mechanism to smooth muscle function, we have constructed a mathematical model based on a hypothetical structure of the smooth muscle contractile unit: a side-polar myosin filament sandwiched by actin filaments, each attached to the equivalent of a Z disk. Model prediction of isotonic shortening as a function of time was compared with data from experiments using ovine tracheal smooth muscle. After equilibration and establishment of in situ length, the muscle was stimulated with ACh (100 M) until force reached a plateau. The muscle was then allowed to shorten isotonically against various loads. From the experimental records, length-force and force-velocity relationships were obtained. Integration of the hyperbolic force-velocity relationship and the linear length-force relationship yielded an exponential function that approximated the time course of isotonic shortening generated by the modeled sliding-filament mechanism. However, to obtain an accurate fit, it was necessary to incorporate a viscoelastic element in series with the sliding-filament mechanism. The results suggest that a large portion of the shortening is due to filament sliding associated with muscle activation and that a small portion is due to continued deformation associated with an element that shows viscoelastic or power-law creep after a step change in force. mathematical model; contractile unit; sliding-filament mechanism THE STRUCTURE OF THE CONTRACTILE unit in smooth muscle is unknown, despite the common belief that the cycling-crossbridge/sliding-filament mechanism of contraction, which operates in striated muscle, is also responsible for smooth muscle contraction. The predominant model for the sarcomere-equivalent contractile unit in smooth muscle is a side-polar myosin (thick) filament sandwiched by two oppositely oriented actin (thin) filaments, each attached to a dense body that is believed to function like a Z disk in striated muscle (18,21,27), as shown in Fig. 1. An important assumption associated with the model is that the sliding of the thick and thin filaments relative to each other is caused by repetitive interaction of the myosin heads (cross bridges) of the thick filament with the thin filaments, in the same manner described for striated muscle (22,23). Such a cross-bridge mechanism for smooth muscle myosin has been observed in experiments where the interaction of isolated individual myosin heads with thin filaments was visualized and quantified directly (14, 15, 28). As predicted by Huxley's 1957 model (22), the ...

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Overview of Length‐Tension Relationships in Isolated Tissue

Kenakin

1998

CP Pharmacology

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This unit describes critical aspects of preparing isolated tissues for experiments to determine the response of specific receptors in the tissue to compounds in a surrounding fluid bath. The two most common methods of evaluating muscle function in pharmacological length‐tension relationships experiments is through measuring isometric and isotonic contraction. In an isometric contraction, which occurs in muscles when they exert force without changing length, the contractile element shortens and the stress transmitted onto the series elastic component is measured in newtons or grams, reflecting the increase in total tension. Isotonic contraction is the shortening of a muscle under a constant load. A key factor in the sensitivity of an isolated tissue receptor system is the resting length under which the muscle is mounted. A discussion of important issues relating to resting length is included.

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Force-velocity characteristics of respiratory airway smooth muscle

Cited by 106 publications

References 0 publications

Effect of duration of vagal stimulation on shortening velocity of in vivo canine trachealis muscle.

Effect of duration of vagal stimulation on shortening velocity of in vivo canine trachealis muscle.

Time course of isotonic shortening and the underlying contraction mechanism in airway smooth muscle

Overview of Length‐Tension Relationships in Isolated Tissue

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