Effects of nociceptin/orphanin FQ on cross-organ sensitization in rat model with visceral hypersensitivity / 中华消化杂志

ABSTRACT

Objective To investigate the effect of nociceptin/orphanin FQ (N/OFQ) on crossorgan sensitization and bladder function disorders in rat model with visceral hypersensitivity. Methods The model of cross-organ sensitization was induced by basic OVA-sensitization combined with colon mustard oil instillation in 44 female SD rats. All rats were then divided into control group (n= 14,infusion with 0.9% NaCl solution), model group (n= 14) and N/OFQ group (n= 16, infusion with N/OFQ). The anti-nociceptive effect of N/OFQ were evaluated by using the visceromotor response (VMR) to grade bladder distention (0. 5～2.0 ml, 20 s). Bladder function was evaluated with the cystometry by measuring voiding pressure and micturition frequency. Results The rats in model group had a significant increase of VMR response at 1.0 ml, 1.5 ml and 2.0 ml of pressure when compared to those in control group (P=0. 006,0. 015 and 0. 0331, respectively). However, N/OFQ treatment was able to reverse the increased VMR response in N/OFQ group at 1.5 ml and 2.0 ml of pressure (P=0. 016 and 0. 031, respectively). It was showed that mustard oil significantly reduced bladdervoiding pressure (P＜0. 01) and significantly increased micturition frequency (P＜0.01)in model group when compared to control group. The N/OFQ reversed the decrease of voiding pressure (P=0. 0038) and the increase of micturition frequency in N/OFQ group( P = 0. 001). Conclusions These findings indicate that the rat model of cross-organ sensitization was able to be established successfully by the basic OVA-sensitization combined with colon mustard oil instillation. N/OFQ has an antinociceptive effect on cross-organ hypersensitivity and attenuates changes in bladder urodynamic function.