Series elastic component of tracheal smooth muscle

Stephens, N. L.; Kromer, U.

doi:10.1152/ajplegacy.1971.220.6.1890

Cited by 31 publications

(11 citation statements)

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“…3), comparable to the values in both time and developed pressures observed in situ studies by Palombini and Coburn (1972). 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).…”

Section: Vagal Stimulation Wassupporting

confidence: 81%

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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: 81%

“…The change in muscle length can be separated into two distinct phases ; 1. a rapid shortening phase presumably due to recoil of the series elastic component (Stephens and Kromer 1971), and 2. a relatively slow phase of shortening of the contractile elements preceded by transient instabilities.…”

Section: Resultsmentioning

confidence: 99%

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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“…The amount of series elasticity in the portal vein greatly exceeds that in skeletal muscle (15). It also exceeds that in cardiac (2, 3) and tracheal muscle (19) but is comparable to the value that has been reported for intestine (7,20). Injured tissue at the ends of the vascular preparation may contribute significantly to the series elastic element.…”

Section: Circuuticn Rtstmrb Vol XXXII Fibrtury 197}supporting

confidence: 78%

Active State in the Smooth Muscle of the Rat Portal Vein in Relation to Electrical Activity and Isometric Force

Johansson

1973

Circulation Research

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Contractile activity in smooth muscle is usually too variable to permit a meaningful analysis of the time course of the active state. A regular activity of uniform contractions was obtained in the present experiments on isolated rat portal veins by simultaneous increases in the external potassium and calcium concentrations. The contractions were associated with electrical discharges which lasted between 0.8 and 1.5 seconds. The active state during these uniform contractions was determined from the shortening velocities after isotonic releases and from the redevelopment of tension after controlled releases. Results obtained with the two methods agreed satisfactorily. The active state increased over the first 0.4-0.6 seconds. Suggestive evidence of a plateau phase was found in some experiments. The active state clearly began to fall about 1 second after the start of the contraction, and this fall coincided with the fall in the first time derivative of isometric force (dP/dt). The maximal intensity of the active state was, on the average, 173% of the maximal isometric force. During isometric contractions, the series elastic element was stretched by as much as 1535 of the total muscle length. Active-state values were therefore corrected for changes in contractile element length. The curve then obtained might represent the time course of the level of activation, reflect variations in internal calcium concentration, and relate to the electrical response. Concepts developed for the mechanics of striated muscle can apparently be applied to propagating vascular smooth muscle, and this applicability might help to clarify electromechanical relations and the actions of vasoactive substances in blood vessels.KEY WORDS vascular smooth muscle quick release excitation-contraction coupling effects of potassium and calcium sucrose-gap method series elasticity

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“…The relatively small series elastic component that we have found in TSM (Stephens and Kromer 1971) n~ininmizes changes in internal geometry that occur when the contractile element shortens on stimulation.…”

Section: Hfatesials and Methodsmentioning

confidence: 64%

Study of reversibility of effects of hypoxia in airway smooth muscle

Stephens¹

1977

Can. J. Physiol. Pharmacol.

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We have shown in the past that hypoxia impairs contractile activity in tracheal smooth muscle (TSM). This was associated with partial uncoupling of mitochondria. It remained to be determined whether these changes were reversible. The TSM model was felt to be superior to the isolated mitochondria since it was likely to be free from artefacts inherent in procedures involving homogenisation and extraction. We report here that the oxygen uptake rates of the isolated, mechanically active TSM were increased in the posthypoxia recovery period when compared with the prehypoxia active muscle. Mechanical recovery was complete.

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Series elastic component of tracheal smooth muscle

Cited by 31 publications

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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.

Active State in the Smooth Muscle of the Rat Portal Vein in Relation to Electrical Activity and Isometric Force

Study of reversibility of effects of hypoxia in airway smooth muscle

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