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@#Objective To study the effects of nitroglycerin on leak point pressure of chronic complete spinal cord injury female rats. Methods Models of chronic complete spinal cord injury in female rats were established. Changes of leak point pressure were investigated following nitroglycerin 3 mg intraperitoneal injection. Results Leak point pressure decreased from (32.27±15.00) cmH2O to (23.29±9.46) cmH2O. Conclusion There was obvious descent of leak point pressure of chronic complete spinal cord injury female rats following nitroglycerin intraperitoneal injection.
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@#Objective To study the effects of nitroglycerin on urethral sphincter of chronic complete spinal cord injury female rats in vitro. Methods 30 SD female rats with 3 months old were transected at T10 spinal cord. After 8 weeks, the 10 rats with BBB scores ≤5 were selected as experimental group, and other 10 normal rats as control group. The difference of tension in both proximal segment (urethral smooth muscle strips) and distal segment (external urethral sphincter muscle strips) were surveyed before and after nitroglycerin 0.5 mg administration in bath. Results The tension of distal segment in control group reduced from (640.50±91.79) mg to (597.50±92.61) mg, and from (485.50±68.94) mg to (459.90±69.51) mg in experimental group. The difference between proximal segment and distal segment were (222.30±12.14) mg and (42.00±7.86) mg before and after administration in control group, and were (223.00±15.78) mg and (25.60±5.17) mg in experimental group. Conclusion The administration of nitroglycerin 0.5 mg in bath can reduce the tension of both urethral smooth muscle and external urethral sphincter in both normal and spinal cord injured rats. The relaxative effect on external urethral sphincter muscle of normal rats exceed that of injured ones, but approximate on urethral smooth muscle.
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@#Objective To investigate the neuronal nitric oxide synthase (nNOS) distribution in intramural striated sphincter of female rats. Methods 4 female Wistar rats were anesthetized with chloral hydrate. The whole bladder and urethra specimen were harvested, fixed in formalin and imbedded in paraffin wax. Longitudinal and transverse sections were developed with 2 urethra respectively. Routine HE staining and Mallory phosphotungstic acid-hematoxylin staining were used for observation of urethral microstructure. nNOS distribution in intramural striated sphincter was determined with immunohistochemical staining. Results The urethras of female Wistar rat were tubular structure about 1.5～2.0 cm long. From outside inward,the structure included circular striated muscle layer,circular smooth muscle layer,longitudinal smooth muscle layer,dense connective tissue and epithelium. The longitudinal sections showed intramural striated muscle predominates the middle and distal third,not the whole urethral length. The transverse sections showed intramural striated muscle is closed ring shape,about 5～10 layers uneven distributed with more layers in the posterior wall than in the front wall. Strong positive expression of nNOS immunoreactivity was found in some intramural striated muscle fiber. Conclusion nNOS expresses in some intramural striated muscle fiber, surggesting nitric oxide may play an important role on intramural striated sphincter.
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@# Injection of botulinum toxin type A (BTX-A) seems to have a positive therapeutic effect in multiple urological conditions, including detrusor external sphincter dyssynergia, voiding dysfunction, painful pelvic floor, bladder overactivity, frequency-urgency syndrome, interstitial cystitis, benign prostatic hyperplasia, and be thought as a novel and promising treatment for a variety of lower urinary tract dysfunctions within the urological field. However, there is a long way to go to assess the clinical efficacy of this form by randomized, double blinded, placebo-controlled trials.