Objective: 

The participation of vasoactive intestinal peptide (VIP) in various normal and pathological processes is under intensive investigations lately. It was shown that diabetes mellitus is associated with a decrease in VIP content of gastrointestinal tract. The role of VIP in diabetes is not clear, and will be studied by us in the near future. VIP possesses a potent antioxidant, anti-inflammatory and neuroprotective activity, suggesting that this neuropeptide is a prospective protective peptide.

Methods: 

Guinea-pig detrusor strips isolated from urinary bladder were mounted for tension recording in small organ baths. The strips were subjected to electrical field stimulation (5 s trains, 0.05 ms duration, 40 Hz, 50 V) with 15-min intervals between stimulations. The nerves were subjected to 60 min of ischemia followed by 150 min of reperfusion. VIP was added to the perfusing Krebs solution at 0.1, 0.3 and 1 microM concentrations and kept during the whole ischemia plus the first 30 min of reperfusion. Inhibition of lipid peroxidation was assessed based on the oxidation of linoleic acid initiated by ABAP. Five increasing concentrations VIP were added to the peroxidising system.

Results: 

VIP improved the neurogenically-induced contractions during ischemia and reperfusion as compared to the untreated controls. The antioxidant activity of VIP assessed as its capability to scavenge peroxyl radicals during linoleic acid oxidation was 6.42 ± 0.13 pIC50 M.

Conclusions: 

VIP counteracts the damage suffered by neurons in the urinary bladder, exposed to ischemia-reperfusion conditions.

Acknowledgement: Supported by Grant DDVU-02-24/2010 from the National Science Fund, Sofia, Bulgaria.