تغييرات جريان خون پوستي به دنبال تزريق مرفين و نقش نيتريك اكسايد در بروز اين تغييرات

Skin blood flow changes due to morphine and the role of nitric oxide

The effect of morphine on skin blood flow (SBF) and the involvement of NO were investigated using laser Doppler flowmetry (LDF) technique. The results showed that subcutaneous injection of morphine (3 mg/kg) significantly increased SBF in two serial steps and then reduced it until the end of the experiment. An increase in rectal temperature (1.4 °C) and a decrease in tail blood pressure (18.6%) were observed. Although the first phase of SBF increment was immediately after morphine injection with no significant change in temperature and blood pressure, but the second phase of SBF increase was associated with temperature increase and the falling phase of SBF was associated with a reduction in BP. In addition, L-NAME (SC, 5 mg/kg) reversed the first phase of morphine-induced SBF increase, but had no effect on the second phase and the reduction phase of SBF. On the other hand, L-NAME at a dose of 20 mg/kg inhibited both phases of SBF increase and had no effect on the falling phase of SBF. Based on these results, it can be concluded that morphine, in addition to its direct effect on SBF (immediately after injection), has also indirect effects on SBF due to its influence on body temperature and blood pressure. Meanwhile, the concurrent effect of morphine in induction of hyperthermia and hypotension continue up to the end of the experiment and SBF increase was transient due to temperature increase. On the other hand, inhibition of NO release reduced SBF and had no significant effect on SBF change due to morphine hypotensive effect.