Multidirectional contraction of human hypertrophied prostate.

Abstract 1. 1. The purpose of the present investigation is to evaluate muscle contraction in two directions (longitudinal and circumferential to urethra) physiologically and morphologically for α-adrenoceptor agonists. 2. 2. Norepinephrine (10 −7 −10 −4 M), phenylephrine (10 −7 −10 −4 M) and clonidine (10 −7 −10 −4 M) induced contractions in a dose-dependent manner on human prostate from patients with benign prostatic hypertrophy (BPH). 3. 3. No significant differences were observed between longitudinal and circumferential directions of human prostate in 50% of the maximal muscle contraction (EC 50 values) and the maximal muscle contractions caused by any agents used. 4. 4. Morphometric analysis for muscle in prostates was performed using formalin-fixed, paraffin-embedded sections stained by the Mallory-Azan method. 5. 5. There was no significant difference in the density of the muscle area between longitudinal and circumferential directions of prostatic strips. 6. 6. These results suggest that there are no significant differences in responsiveness of α-adrenoceptor agonists and the smooth muscle contents in longitudinal and circumferential directions to urethra, for human hypertrophied prostate.