Effect of stress on hippocampal nociceptin expression in the rat

Paola Nativio, Esterina Pascale, Angelo Maffei, Sergio Scaccianoce, Francesca Passarelli

Research output: Contribution to journalArticlepeer-review


Nociceptin/orphanin FQ (N/OFQ) peptide and its receptor are not only ubiquitously expressed in mammalian brain and spinal cord but are also abundant in limbic structures, particularly in the hippocampus. The widespread distribution of N/OFQ reflects the broad spectrum of its biological actions such as nociception, food intake, spontaneous locomotor activity, and learning and memory processes. Since the hippocampus is involved in the control of adrenocortical activity, its role in stress-related phenomena is well characterized. In male Wistar rats, we first examined the effects of acute restraint stress (120 min) on the brain immunohistochemical localization of N/OFQ. The analysis carried out on sections obtained at the onset of stress revealed enhanced expression of N/OFQ in CA1, CA3, and the dentate gyrus as well as increased plasma corticosterone concentrations. Next, we examined whether endogenous glucocorticoid hormone plays a role in the modulation of hippocampal N/OFQ expression in response to stress. To this end, rats were injected with corticosterone (1 mg/kg) or subjected to restraint stress 1 week after adrenalectomy. Two hours after corticosterone administration, plasma glucocorticoid concentrations were comparable to those observed after restraint stress, while N/OFQ expression had significantly increased in all the hippocampal subfields examined. By contrast, in adrenalectomized rats, stress did not modify protein expression. These results confirm that stress can affect N/OFQ expression and that glucocorticoids may constitute hormonal mediators of this complex interplay.

Original languageEnglish
Pages (from-to)378-384
Number of pages7
Issue number4
Publication statusPublished - Jul 2012


  • Adrenalectomy
  • Corticosterone
  • Hippocampus
  • Limbic system
  • Nociceptin
  • Restraint stress

ASJC Scopus subject areas

  • Behavioral Neuroscience
  • Endocrine and Autonomic Systems
  • Physiology
  • Psychiatry and Mental health
  • Neuropsychology and Physiological Psychology


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