Comparative length-tension relationship of urinary bladder strips from hamsters, rats, guinea-pigs, rabbits and cats

Longhurst, Penelope A.; Kang, Jianshe; Wein, Alan J.; Levin, Robert M.

doi:10.1016/0300-9629(90)90069-5

Cited by 28 publications

(20 citation statements)

References 4 publications

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“…These data have also been corroborated by Longhurst et al [5] who noted that in several species comparative length-tension curves for bladder smooth muscle gave very similar results with maximal force generated at a point 2.5 times the slack length. This paper differs by adding the obser vation that the error incurred in studying the muscle strips at a fixed length is 11% and equal across the groups studied here.…”

Section: Discussionsupporting

confidence: 78%

What Is the Most Accurate Way to Study the Active Properties of Bladder Smooth Muscle?

Zderic¹,

Lv²,

Haab³

et al. 1994

Pharmacology

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There is often disagreement over the optimal method by which to study the active properties of smooth muscle. While some favor setting smooth muscle strips at a resting or passive tension of 1 g, others have argued in favor of determining the L_o or optimal length for maximal force generation for each individual strip. Setting each strip to its individual L_o is tedious, especially if one is dealing with multiple strips during one experiment. Is it possible to study smooth muscle strips at an average length at which most strips of similar dimensions exhibit their maximal force, and if this method is used to what extent does it underestimate the maximal force generated? When comparing bladder smooth muscle strips 1 cm long from pregnant versus virginal rabbits, the average length at which maximal force was generated was 2.41 and 2.45 cm, respectively (p = n.s.). Studying all strips at a length of 2.5 cm (2.5 × the slack length) would have resulted in a 10% underestimate of the maximal force within each group (p = n.s.). We conclude that comparative bladder smooth muscle strip studies can be accurately carried out at an average fixed length provided that preliminary studies are done to determine the length-tension relationships for the specific experimental situation.

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Section: Discussionsupporting

confidence: 78%

What Is the Most Accurate Way to Study the Active Properties of Bladder Smooth Muscle?

Zderic¹,

Lv²,

Haab³

et al. 1994

Pharmacology

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show abstract

“…How the actomyosin crossbridges in the bladder are prepared and positioned to contract efficiently over this broad length range during the filling phase remains to be determined. Earlier studies have shown that DSM produces a somewhat parabolic L-T a curve with ascending and descending limbs and a nonlinear L-T p curve that exhibits greater tension at longer lengths, 16,29,30 very similar to the curves produced by striated muscles 9 and by other smooth muscles. 10,14 In skeletal muscle, the L-T a and L-T p relationships are considered to be static, with a single maximum T a value and a single T p value corresponding to each muscle length.…”

Section: Introductionmentioning

confidence: 85%

“…3a, points 9-13) and then multiple contractions at an intermediate length, 9 mm (Fig. 3a, points [14][15][16][17][18][19]. Based on our prior studies, we expected to find that multiple contractions at each length increased T a at that length.…”

Section: L-t Curve Adaptation Protocolsmentioning

confidence: 91%

Length Adaptation of the Passive-to-Active Tension Ratio in Rabbit Detrusor

2010

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The passive and active length-tension (L-T (p) and L-T (a)) relationships in airway, vascular, and detrusor smooth muscles can adapt with length changes and/or multiple contractions. The present objectives were to (1) determine whether short-term adaptation at one muscle length shifts the entire L-T (a) curve in detrusor smooth muscle (DSM), (2) compare adaptation at shorter versus longer lengths, and (3) determine the effect of adaptation on the T (p)/T (a) ratio. Results showed that multiple KCl-induced contractions on the descending limb of the original L-T (a) curve adapted DSM strips to that length and shifted the L-T (a) curve rightward. Peak T (a) at the new length was not different from the original peak T (a), and the L-T (p) curve shifted rightward with the L-T (a) curve. Multiple contractions on the ascending limb increased both T (a) and T (p). In contrast, multiple contractions on the descending limb increased T (a) but decreased T (p). The T (p)/T (a) ratio on the original descending limb adapted from 0.540 +/- 0.084 to 0.223 +/- 0.033 (mean +/- SE, n = 7), such that it was not different from the ratio of 0.208 +/- 0.033 at the original peak T (a) length, suggesting a role of length adaptation may be to maintain a desirable T (p)/T (a) ratio as the bladder fills and voids over a broad DSM length range.

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“…It was shown, in separate experiments, that contractility of isolated rat bladder strips in response to field stimulation (FS) and cholinergic stimulation is significantly greater than that of isolated rabbit bladder strips [7][8][9]. Similarly, whole rat bladder in vitro is capable of generating 3-4 times more intravesical pressure than whole rabbit bladder in vitro in response to FS and carbachol [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Rabbit versus Rat Urinary Bladder: Effects of in vitro Hypoxia

Whitbeck

Barreto²,

Horan³

et al. 1999

Pharmacology

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Purpose: Studies indicate that bladder hypoxia may be an etiological factor for lower urinary tract dysfunction. Rat and rabbit are two species of experimental animals used frequently to study lower urinary tract function and dysfunction. The objective of this study was to compare directly effects of in vitro hypoxia on contractile responses of rat and rabbit urinary bladder to different forms of stimulation. Methods: Sexually mature male New Zealand White rabbits and Sprague-Dawley rats were compared. Each bladder was excised while the animal was anesthetized, and longitudinal bladder strips were cut, then mounted in organ baths. A tension of 2 g was placed on all strips. Effects of 1, 2, 3 and 4 h hypoxia followed by 1 h of reoxygenation on contractile responses of bladder strips to field stimulation (FS), carbachol (100 μmol/l), ATP (1 mmol/l) and KCl (120 mmol/l) were determined. Results: Contractility, per unit tissue mass, of rat bladder strips was significantly greater than that of rabbit bladder strips in response to FS (all frequencies), carbachol, KCl and ATP. Hypoxia (followed by reoxygenation) resulted in time-dependent progressive reduction in contractile responses of bladder strips to all stimuli. Rat bladder was significantly more sensitive to hypoxia than rabbit bladder in response to FS and carbachol. Hypoxia induced similar effects on rat and rabbit bladder responses to ATP and KCl. Conclusion: Rat bladder neurogenic and cholinergic responses are significantly more sensitive to hypoxia than are those of rabbit bladder, which may be due to the rat bladder’s greater contractile force generation and previously reported higher Ca²⁺-ATPase activity.

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Comparative length-tension relationship of urinary bladder strips from hamsters, rats, guinea-pigs, rabbits and cats

Cited by 28 publications

References 4 publications

What Is the Most Accurate Way to Study the Active Properties of Bladder Smooth Muscle?

What Is the Most Accurate Way to Study the Active Properties of Bladder Smooth Muscle?

Length Adaptation of the Passive-to-Active Tension Ratio in Rabbit Detrusor

Rabbit versus Rat Urinary Bladder: Effects of in vitro Hypoxia

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