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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 storage on relaxant responses to isoprenaline, expressed as potency (pEC50) and efficacy (Emax) as calculated per strip. Strips were tested on the day of surgical removal (day 0) or 1 or 2 days later (day 1 and 2). Each data point represents one patient (16 and 15 strips, respectively, from 11 patients for the day 0 vs. 1 comparison; 10 and 10 strips, respectively, from six patients for the day 0 vs. 2 comparison), whereas the bars represent the group means. Note that the day 0 patients in the upper panel are not necessarily the same as in the lower panel, as each panel only shows patients for whom data on both days were available. **p < 0.05 in a paired, two-tailed t-test vs. corresponding data from day 0.
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Figure 5: Effect of storage on relaxant responses to isoprenaline, expressed as potency (pEC50) and efficacy (Emax) as calculated per strip. Strips were tested on the day of surgical removal (day 0) or 1 or 2 days later (day 1 and 2). Each data point represents one patient (16 and 15 strips, respectively, from 11 patients for the day 0 vs. 1 comparison; 10 and 10 strips, respectively, from six patients for the day 0 vs. 2 comparison), whereas the bars represent the group means. Note that the day 0 patients in the upper panel are not necessarily the same as in the lower panel, as each panel only shows patients for whom data on both days were available. **p < 0.05 in a paired, two-tailed t-test vs. corresponding data from day 0.

Mentions: Isoprenaline concentration-dependently relaxed KCl-contracted human bladder strips (Figure 4). We first explored whether storage for up to 2 days affected the relaxant response to isoprenaline. If only the strips from the patients with data on day 0 and 1 were considered (16 and 15 strips, respectively, from 11 patients), the potency and efficacy of isoprenaline were very similar and the difference not statistically significant (p = 0.5879 and 0.2391, respectively, in a paired t-test; Figure 5). A different situation was observed when looking at patients with data on day 0 and 2 (10 and 10 strips, respectively, from six patients). While storage for 2 days did not affect isoprenaline efficacy, it reduced its potency by 0.70 log units (p = 0.8275 and 0.0017, respectively; Figure 5). Hence, storage for up to 1 day did not affect relaxant responses, whereas 2-day storage maintained isoprenaline efficacy but reduced its potency. Accordingly, only strips from days 0 and 1 were included in the subsequent analyses.


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 storage on relaxant responses to isoprenaline, expressed as potency (pEC50) and efficacy (Emax) as calculated per strip. Strips were tested on the day of surgical removal (day 0) or 1 or 2 days later (day 1 and 2). Each data point represents one patient (16 and 15 strips, respectively, from 11 patients for the day 0 vs. 1 comparison; 10 and 10 strips, respectively, from six patients for the day 0 vs. 2 comparison), whereas the bars represent the group means. Note that the day 0 patients in the upper panel are not necessarily the same as in the lower panel, as each panel only shows patients for whom data on both days were available. **p < 0.05 in a paired, two-tailed t-test vs. corresponding data from day 0.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: Effect of storage on relaxant responses to isoprenaline, expressed as potency (pEC50) and efficacy (Emax) as calculated per strip. Strips were tested on the day of surgical removal (day 0) or 1 or 2 days later (day 1 and 2). Each data point represents one patient (16 and 15 strips, respectively, from 11 patients for the day 0 vs. 1 comparison; 10 and 10 strips, respectively, from six patients for the day 0 vs. 2 comparison), whereas the bars represent the group means. Note that the day 0 patients in the upper panel are not necessarily the same as in the lower panel, as each panel only shows patients for whom data on both days were available. **p < 0.05 in a paired, two-tailed t-test vs. corresponding data from day 0.
Mentions: Isoprenaline concentration-dependently relaxed KCl-contracted human bladder strips (Figure 4). We first explored whether storage for up to 2 days affected the relaxant response to isoprenaline. If only the strips from the patients with data on day 0 and 1 were considered (16 and 15 strips, respectively, from 11 patients), the potency and efficacy of isoprenaline were very similar and the difference not statistically significant (p = 0.5879 and 0.2391, respectively, in a paired t-test; Figure 5). A different situation was observed when looking at patients with data on day 0 and 2 (10 and 10 strips, respectively, from six patients). While storage for 2 days did not affect isoprenaline efficacy, it reduced its potency by 0.70 log units (p = 0.8275 and 0.0017, respectively; Figure 5). Hence, storage for up to 1 day did not affect relaxant responses, whereas 2-day storage maintained isoprenaline efficacy but reduced its potency. Accordingly, only strips from days 0 and 1 were included in the subsequent analyses.

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