Area density of smooth muscle cells and response to endothelin 1 in human hyperplastic prostate.
BACKGROUND
alpha-Agonists and endothelins (ETs) are the only agents that have been proved to induce significant contraction of the prostate. Although the response to phenylephrine (PE) is dependent on the quality of smooth muscle (SM) within the prostate, it is not clear whether the response to ET-1 is also influenced by SM density. We evaluate the relationship between contractile responsiveness to ET-1 and the area density of SM of the human prostate.


METHODS
Specimens were obtained from 17 patients with prostatic hyperplasia that underwent transurethral resection of the prostate. Specimens were used for isometric tension study (PE, KCl and ET) and also for quantitative morphometric analysis.


RESULTS
PE and ET-1 induced dose-dependent contractile responses. There were no significant differences in the average maximum response (E(max)) to these two agents. E(max) to KCl and PE showed direct positive correlations with the area density of SM. E(max) to ET-1 also showed a positive correlation with the SM density, although this relationship was weaker than those for the other two agents. Moreover, there was a strong positive relationship between E(max) to PE, KCl and that to ET-1.


CONCLUSIONS
The area density of SM appeared to significantly influence the contractile response to ET-1 as well as the response to PE and KCl.
Ishigooka
M
M
Department of Urology, Yamagata University School of Medicine, Yamagata, Japan. QZV10733@nifty.ne.jp
Yazawa
H
H
Nakada
T
T
Zermann
D H
DH
D000368:Aged; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000494:pharmacology* / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D009130:Muscle, Smooth / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D010656:Phenylephrine / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology; D011336:Probability; D011467:Prostate / Q000187:drug effects* / Q000473:pathology; D011470:Prostatic Hyperplasia / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D012680:Sensitivity and Specificity; D020728:Transurethral Resection of Prostate
D019332:Endothelin-1; D010656:Phenylephrine; D011189:Potassium Chloride