Research on the mechanism of voiding in the neurogenic bladder due to spinal cord injury and cerebral infarction

1.膀胱测压法检测膀胱内注射ET-1对正常清醒大鼠排尿反射的影响。ET-1在10^lt；-6M至10^lt；-5M缩短收缩间期。此作用可被ET_A受体拮抗剂BQ123拮抗，但不能被ET_B受体拮抗剂BQ788拮抗。ET_B受体激动剂沙拉毒素S6c无作用。2.观察了薄荷脑对乙酰胆碱和αβ-亚甲基三磷酸腺苷引起的大鼠逼尿肌收缩的影响。3.膀胱内注入薄荷醇对乌拉坦麻醉正常大鼠排尿反射的影响。3 mm薄荷脑缩短收缩间期。在辣椒素敏感的C纤维脱敏大鼠中也观察到了这种作用。这些结果表明，薄荷醇抑制逼尿肌的收缩，但膀胱内注入薄荷醇诱导的排尿反射不依赖于辣椒素敏感的C纤维。4.膀胱内注入薄荷醇对清醒脊髓损伤大鼠排尿的影响。1 mm和3 mm薄荷醇可增加膀胱容量和残气量，减少排尿量和排尿压力。这些效应很可能是由于薄荷醇抑制逼尿肌收缩所致。对于脊髓损伤患者，膀胱内应用薄荷醇可能有益于通过清洁间歇插管正常排空膀胱，以防止尿失禁和高压排空。

1.Effects of intravesical infusion of ET-1 on micturition reflex were examined by cystmetry in normal conscious rats. ET-1 at 10^<-6>M to 10^<-5>M shortened intercontraction interval. The effect was antagonized by ET_A receptor antagonist BQ123 but not by ET_B receptor antagonist BQ788. ET_B receptor agonist sarafotoxin S6c had no effect. These data suggest that activation of ET_A receptor in the urinary bladder induces the micturiton reflex.2.Effects of menthol on contractions of rat isolated detrusor smooth muscle indued by acetylcholine and αβ-methylene ATP were examined. Menthol strongly inhibited contractions induced by both of them.3.Effects of intravesical infusion of menthol on micturition reflex were examined by cystmetry in urethane anesthetized normal rats. 3mM menthol shortened intercontraction interval. And this effect was also observed in capsaicin-sensitive C-fiber desensitized rats.These result suggest that menthol inhibits detrusor smooth muscle contractility but intravesical infusion of menthol induces micturition reflex independent from capsaicin-sensitive C-fiber.4.Effects of intravesical infusion of menthol on micturition were examined by cystmetry in conscious spinal cord injured rats. Menthol at 1mM and 3mM increased bladder capacity and residual volume and decreased voided volume and reduced micturition pressure. It is likely that these effects were due to inhibition of detrusor smooth muscle contractility by menthol. Intravesical administrarion of menthol may be beneficial to spinal cord injured patients normally emptying their bladder by clean intermittent catherterization for prevention of incontinence and high pressure void.