Objective: To explore the role of 5-HT and postsynaptic 5-HT1A receptors in the stress adaptation.
Methods: p-PCA was used to deplete the 5-HT in rats. The 5-HT1A agonist 8-OH-DPAT and antagonist WAY100635 were used to determine the effect of postsynaptic 5-HT1A receptors on the ratso behaviors in the Elevated Plus-Maze test, the Forced Swimming test, and the Morris Water Maze test.
Results: Compared with the intact rats, the 5-HT depleted rats showed more seriously anxious behaviors in the Elevated Plus-Maze test and more obvious learned helplessness in the Forced Swimming test. After having been stressed the 5-HT depleted rats showed significantly impaired learning and memory compared with the intact rats according to Morris Water Maze test. Activation of postsynaptic 5-HT1A receptors by 8-OH-DPAT in the 5-HT depleted rats or the 5-HT depleted stress rats significantly decreased the symptoms of anxiety and learned helplessness behaviors which were prevented by the treatment of WAY100635. The 8-OH-DPAT and WAY100635 had no obvious effect on the 5-HT depletion or 5-HT depleted stress rats in the Morris Water Maze test.
Conclusion: Deficiency of 5-HT in rats may suppress its ability to stress adaptation. Activation of post-synaptic 5-HT1A receptors can attenuate the anxiety and depressive behavior symptoms, and facilitate rats to adapt stress.