Establishment of detrusor hyperreflexia models in conscious rats

We tried to establish detrusor hyperreflexia models in conscious rats placed in a restraining cage. Intravesical instillation of 30% xylene, an irritant known to activate the capsaicin-sensitive sensory fiber in the afferent branch of the micturition reflex, produced detrusor hyperreflexia characterized by decreases in both bladder capacity and urine volume in the cystometrogram. At this time, the bladder tissue showed experimental cystitis with edema and hemorrhage in the submucosa and a slight increase in prostaglandin E2 content, which is considered to stimulate directly and/or indirectly the capsaicin-sensitive sensory fiber. On the other hand, bilateral transactions of the hypogastric nerve, considered to inhibit the micturition reflex, also produced detrusor hyperreflexia, but the bladder tissue did not show any experimental cystitis. In conclusion, these detrusor hyperreflexia models in conscious rats appear to be useful for evaluating the effects of various agents including anti-pollakiuria agents on bladder function.