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

1.用膀胱法观察正常意识大鼠膀胱内输注ET-1对排尿反射的影响。ET-1在10^<-6>M至10^<-5>M间缩间隔缩短。ET_A受体拮抗剂BQ123可拮抗该效应，而ET_B受体拮抗剂BQ788不能拮抗该效应。ET_B受体激动剂sarafotoxin S6c无作用。这些数据表明，激活膀胱内的ET_A受体可诱导排尿反射。观察薄荷醇对乙酰胆碱和αβ-亚甲基ATP诱导的大鼠离体逼尿肌平滑肌收缩的影响。薄荷醇强烈抑制这两种物质引起的收缩。采用膀胱测量法观察尿路麻醉大鼠膀胱输注薄荷醇对排尿反射的影响。3mM薄荷醇缩短了收缩间隔。在对辣椒素敏感的c纤维脱敏的大鼠中也观察到这种效果。这些结果表明薄荷醇抑制逼尿肌平滑肌收缩，但膀胱内输注薄荷醇可诱导独立于辣椒素敏感的c -纤维的排尿反射。采用膀胱测量法观察脑内输注薄荷醇对脊髓损伤大鼠排尿的影响。薄荷醇在1mM和3mM时膀胱容量和残余体积增加，排尿量减少，排尿压力降低。这些影响可能是由于薄荷醇抑制逼尿肌平滑肌收缩。脑内薄荷醇可能有利于脊髓损伤患者通过清洁间歇导尿排空膀胱，以预防尿失禁和高压空洞。

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.