Nerve induced responses and force-velocity relations of regenerated detrusor muscle after subtotal cystectomy in the XXXX .

@entity3159 @entity16312 @entity861 @entity2647 @entity35 @entity5591 @entity5402
AIMS: To study the pharmacological and mechanical properties of newly developed detrusor muscle after subtotal cystectomy, to explore if the regenerated detrusor has characteristics similar to the normal bladder base, from which it regenerated, or to the normal bladder body which it replaces. METHODS: Partial cystectomy was performed in female @entity35 . Fifteen weeks later, detrusor strips were cut from supratrigonal and equatorial segments. Unoperated @entity35 served as controls. Responses to field stimulation were obtained in the absence and presence of @entity5591 , @entity3159 , and @entity16312 blockade. Dose-response curves were obtained for @entity5402 , @entity861 , and @entity2647 . Force-velocity data were obtained on maximally activated chemically skinned preparations. RESULTS: Maximal contractile response to field stimulation was 60% of that to high-K+ with no difference between strips from control and cystectomy bladders. @entity3159 had no effect. @entity5591 decreased maximal response of supratrigonal strips to 62 +/- 6 (controls) and 61 +/- 4% (operated) of that without blocker. For equatorial strips the decrease was to 81 +/- 5 (controls) and 58 +/- 8% (operated). Frequency-response relations were obtained during blockade with @entity5591 , @entity861 , and @entity3159 . Supratrigonal strips showed a pronounced additional inhibition up to 40 Hz. Equatorial strips from controls were completely inhibited at all frequencies. Equatorial strips from operated bladders were inhibited up to 20 Hz but not at 40 and 60 Hz. @entity5402 EC(50) values were similar in all groups. Maximum response to @entity2647 was 10-20% of high-K+ response. Maximal shortening velocity (Vmax) was similar in control supratrigonal and equatorial strips, but was significantly lower in the operated bladders. CONCLUSIONS: (1): A regional difference exists in pharmacological properties of control detrusor, with a considerable contractile response to stimulation remaining in the supratrigonal muscle after simultaneous cholinergic, adrenergic, and purinergic blockade. (2): The new detrusor was functionally well innervated with no supersensitivity to muscarinic stimulation. (3): The newly formed bladder body had pharmacological properties specific for the supratrigonal segment from which it had developed. (4): There was no regional difference in force-velocity characteristics of the control detrusor. (5): The lowered Vmax in the newly formed bladder might thus be related to growth and regeneration of muscle cells.
