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Human Urinary Bladder Strip Relaxation by the β-Adrenoceptor Agonist Isoprenaline: Methodological Considerations and Effects of Gender and Age.

Schneider T, Fetscher C, Michel MC - Front Pharmacol (2011)

Bottom Line: Storage of detrusor strips in cold buffer for up to 2 days did not affect contractile responses to KCl or efficacy of isoprenaline to cause relaxation but significantly affected the isoprenaline potency.The type (KCl vs. passive tension) or strength of contractile stimulus had only minor effects on isoprenaline responses although these differences reached statistical significance in some cases.Similarly, gender and age had only minor if any effects on KCl-induced contraction or isoprenaline-induced relaxation, but the current data are too limited for robust conclusions.

View Article: PubMed Central - PubMed

Affiliation: Departments of Urology and Medicine, University of Duisburg-Essen Essen, Germany.

ABSTRACT
The present study was primarily designed to explore various methodological aspects related to organ bath experiments evaluating human detrusor relaxation by the β-adrenoceptor agonist isoprenaline. Data are based upon a series of 30 consecutive patients, and this cohort was also used to explore possible effects of gender and age. KCl-induced contraction was related to strip length but not weight or cross-sectional area, indicating that the former is most suitable for data normalization. Storage of detrusor strips in cold buffer for up to 2 days did not affect contractile responses to KCl or efficacy of isoprenaline to cause relaxation but significantly affected the isoprenaline potency. No such alterations were observed with up to 1 day of cold storage. The type (KCl vs. passive tension) or strength of contractile stimulus had only minor effects on isoprenaline responses although these differences reached statistical significance in some cases. Similarly, gender and age had only minor if any effects on KCl-induced contraction or isoprenaline-induced relaxation, but the current data are too limited for robust conclusions. In summary we have evaluated experimental conditions for the testing of human detrusor strip contraction and relaxation which should be useful for future larger studies.

No MeSH data available.


Related in: MedlinePlus

Effect of type of contractile stimulus (KCl vs. passive tension) on the potency and efficacy of isoprenaline to relax human detrusor strips. Bars describe group means whereas each data point represents one patient (2–4 strips being tested per patient).
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Figure 6: Effect of type of contractile stimulus (KCl vs. passive tension) on the potency and efficacy of isoprenaline to relax human detrusor strips. Bars describe group means whereas each data point represents one patient (2–4 strips being tested per patient).

Mentions: We next explored the role of type and strength of contractile stimulus for the isoprenaline-induced relaxation. Paired relaxation data against passive tension (10 mN) and KCl-induced tone as assessed within one patient were available for 16 pairs of strips from five patients as measured on day 0 and 1. While the potency and efficacy of isoprenaline was numerically higher against passive tension than against KCl (Figure 4), this difference did not reach statistical significance (p = 0.0832 and 0.3713, respectively; Figure 6). We then used the heterogeneity in KCl-induced tension to explore the role of strength of contractile stimulus. Based upon 54 strips from days 0 and 1, the potency of isoprenaline was not significantly related to strength of contractile stimulus (r2 = 0.0141; p = 0.3931); in contrast, the efficacy of isoprenaline was weakly but significantly associated with contractile tone, i.e., a greater initial tension was correlated with a greater degree of relaxation (r2 = 0.1651; p = 0.0023; Figure 7).


Human Urinary Bladder Strip Relaxation by the β-Adrenoceptor Agonist Isoprenaline: Methodological Considerations and Effects of Gender and Age.

Schneider T, Fetscher C, Michel MC - Front Pharmacol (2011)

Effect of type of contractile stimulus (KCl vs. passive tension) on the potency and efficacy of isoprenaline to relax human detrusor strips. Bars describe group means whereas each data point represents one patient (2–4 strips being tested per patient).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3108483&req=5

Figure 6: Effect of type of contractile stimulus (KCl vs. passive tension) on the potency and efficacy of isoprenaline to relax human detrusor strips. Bars describe group means whereas each data point represents one patient (2–4 strips being tested per patient).
Mentions: We next explored the role of type and strength of contractile stimulus for the isoprenaline-induced relaxation. Paired relaxation data against passive tension (10 mN) and KCl-induced tone as assessed within one patient were available for 16 pairs of strips from five patients as measured on day 0 and 1. While the potency and efficacy of isoprenaline was numerically higher against passive tension than against KCl (Figure 4), this difference did not reach statistical significance (p = 0.0832 and 0.3713, respectively; Figure 6). We then used the heterogeneity in KCl-induced tension to explore the role of strength of contractile stimulus. Based upon 54 strips from days 0 and 1, the potency of isoprenaline was not significantly related to strength of contractile stimulus (r2 = 0.0141; p = 0.3931); in contrast, the efficacy of isoprenaline was weakly but significantly associated with contractile tone, i.e., a greater initial tension was correlated with a greater degree of relaxation (r2 = 0.1651; p = 0.0023; Figure 7).

Bottom Line: Storage of detrusor strips in cold buffer for up to 2 days did not affect contractile responses to KCl or efficacy of isoprenaline to cause relaxation but significantly affected the isoprenaline potency.The type (KCl vs. passive tension) or strength of contractile stimulus had only minor effects on isoprenaline responses although these differences reached statistical significance in some cases.Similarly, gender and age had only minor if any effects on KCl-induced contraction or isoprenaline-induced relaxation, but the current data are too limited for robust conclusions.

View Article: PubMed Central - PubMed

Affiliation: Departments of Urology and Medicine, University of Duisburg-Essen Essen, Germany.

ABSTRACT
The present study was primarily designed to explore various methodological aspects related to organ bath experiments evaluating human detrusor relaxation by the β-adrenoceptor agonist isoprenaline. Data are based upon a series of 30 consecutive patients, and this cohort was also used to explore possible effects of gender and age. KCl-induced contraction was related to strip length but not weight or cross-sectional area, indicating that the former is most suitable for data normalization. Storage of detrusor strips in cold buffer for up to 2 days did not affect contractile responses to KCl or efficacy of isoprenaline to cause relaxation but significantly affected the isoprenaline potency. No such alterations were observed with up to 1 day of cold storage. The type (KCl vs. passive tension) or strength of contractile stimulus had only minor effects on isoprenaline responses although these differences reached statistical significance in some cases. Similarly, gender and age had only minor if any effects on KCl-induced contraction or isoprenaline-induced relaxation, but the current data are too limited for robust conclusions. In summary we have evaluated experimental conditions for the testing of human detrusor strip contraction and relaxation which should be useful for future larger studies.

No MeSH data available.


Related in: MedlinePlus