Relationship between exposure to stressful agents and oxidative stress could function as a possible nexus between stress related pychopathologies, such as major depression or anxiety, and stress related physiopathologies. Oxidative changes associated to acute restraint and to 5-HT1A receptor modulation was evaluated in rat serum/plasma. Animals submitted to 1 h of acute restraint, and/or pre-treated with the 5-HT1A receptor agonist 8-OH-DPAT and the 5-HT1A receptor antagonist WAY-100635, were decapitated. Plasma and serum samples were then obtained by centrifugation of trunk blood and stored at -80ordm; C until analysis. Levels of total antioxidant status (TAS), superoxide dismutase activity, total thiol groups, lipid hydroperoxides and advanced oxidation protein products were measured following previously described methods, automatized for a COBAS MIRA S analyzer.

Both immobilization stress and treatments with 5-HT1A serotonergic receptor ligands, induce a pro-oxidative status in serum, the main effect being the reduction of total SOD activity and total thiol groups, and thereby affecting TAS. Stepwise Wald logistic regression showed that modifications of total thiol groups are independently associated to changes in TAS (O.R. = 1.248; 95%I.C: 1.055 – 1.476; p<0.05). In conclusion, acute restraint induces an pro-oxidative status as well as the use of drugs with a 5-HT1A binding. We consider of clinical relevance the results obtained in this work.

This work has been supported by a grant from the Spanish DGICYT 99-0159. We thank Mrs. Maria I. Soler from the University of Málaga as English reviewer.