Proceedings of The Physiological Society
University of Manchester (2010) Proc Physiol Soc 19, PC240
An investigation on the analgesic effects of oxytocin in mice model of painful diabetic neuropathy
M. Ozcan1, A. Ayar2, E. Alcin3, I. Serhatlioglu1, S. Ozcan4, S. Kutlu3, H. Kelestimur3
1. Biophysics, Firat University Faculty of Medicine, Elazig, Turkey. 2. Physiology, Karadeniz Technical University, Trabzon, Turkey. 3. Physiology, Firat University, Elazig, Turkey. 4. Anesthesiology, Firat University, Elazig, Turkey.
In addition to essential role in parturition and lactation, oxytocin (OT) is known to function as a neuromodulator or neurotransmitter in the brain. It is known that the oxytocinergic system has a modulatory function on nociception but the effect of OT on neuropathic pain is less studied. In this study, the effects of OT on painful diabetic neuropathy in mice were investigated by using in vivo hot plate test. Adult male Balb/C mice were allowed to acclimate to the hot plate (50±0.1°C) for a period of 1 week prior to the experiment. Paw withdrawal latency (PWL) to noxious heat (pain threshold) was determined using hot-plate analgesia meter (following the ethical guidelines for investigations of experimental pain in conscious animals; Zimmermann, 1983). After responding or after the allocated cut-off time of 60 s had elapsed, mice were removed from the plate. Diabetes was induced by intraperitoneal injection of streptozotocin. OT was administered intraperitoneal injection to the animals and hot-plate test was repeated for 6 times at 5 min intervals (n=7 for each groups). Vehicle was administered to the control group (n=7). Pain threshold values were determined and analyzed by Kruskal-Wallis one-way analysis of variance followed by a pairwise comparison using a Dunnett’s t-test on the ranked data. The analgesic effectiveness of different doses of OT was measured. OT (10µg/kg) increased the PWL, only in the 10th minute, compared to same period of control group (P<0.05). 30µg/kg OT significantly increased the pain threshold in both 5th and 10th minute compared to control (P<0.05). The highest dose of OT (100µg/kg) increased the pain threshold in the 5th, 10th and 15th minute (P<0.05). Data from this study indicated, for the first time, that OT has analgesic action in diabetic mice. This result may provide additional insight for therapeutic potential of OT in the treatment of neuropathic pain.
Where applicable, experiments conform with Society ethical requirements