en Behavioral Neuroscience Behavioral Neuroscience Original Original <p align="left" ><p><b><font color="#221e1f" size="1"><font color="#221e1f" size="1">Introduction: </font></font><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1">The concentration of noradrenalin and corticosterone as the two nociception modulators change after fasting or stress situation. The aim of present study was to investigate the effect of food deprivation on formalin-induced nociceptive behaviours and plasma levels of noradrenalin and corticosterone in rats. </font></font></font><b><font color="#221e1f" size="1"><font color="#221e1f" size="1"><p align="justify">Methods: </p></font></font><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1">Food was withdrawn 12, 24 and 48 h prior to performing the formalin test, but </font></font></font><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1">water continued to be available ad libitum. The formalin solution (50 μL, 2%) was injected into plantar surface of hind paw. The nociception responses of the animals during the first </font></font></font><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1">phase (1-7 minutes), the inter-phase (8-14), the phase 2A (15-60) and the phase 2B (61-90) was separately evaluated. The plasma concentrations of noradrenalin and corticosterone were </font></font></font><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1">measured using specific ELISA and IRA kits, according to manufacturer's instructions. </font></font></font><b><font color="#221e1f" size="1"><font color="#221e1f" size="1"><p align="justify">Results: </p></font></font><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1">In contrast to the increasing of 48 h food deprived animals during phase 2, the nociceptive behaviours of 12 and 24 h groups decreased through the interphase, phase 2A </font></font></font><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1">and phase 2B. The injection of formalin in the normal male rats significantly decreased the </font></font></font><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1">plasma level of noradrenalin and corticosterone. Food deprivation for 12 and 24 h increased </font></font></font><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1">noradrenalin level significantly in comparison with control group which has caused by fasting induced antinociceptive behaviours. There was no significant change in food deprivation for 48 </font></font></font><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1">h group. Food deprivation for 12, 24 and 48 h had no effect on corticosterone level in male rats. </font></font></font><b><font color="#221e1f" size="1"><font color="#221e1f" size="1"><p>Discussion: </p></font></font><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1"><font color="#221e1f" face="Times New Roman,Times New Roman" size="1">The present study emphasizes that the acute food deprivation diminished the nociceptive behaviours in the formalin test and show a correlation with increase in plasma noradrenalin level. </font></font></font></b></b></b></b></p> Rat,Food Deprivation,Noradrenalin,Corticosterone,Formalin Test. 341 347 http://bcn.iums.ac.ir/browse.php?a_code=A-10-1-184&slc_lang=en&sid=1 Nematollah Gheibi 1370031947532846003984 1370031947532846003984 No Mohammadreza Saroukhani 1370031947532846003985 1370031947532846003985 No Hassan Azhdari-Zarmehri 1370031947532846003986 1370031947532846003986 Yes