Inducible Nitric Oxide Synthase Inhibition in the Medial Prefrontal Cortex Attenuates the Anxiogenic-Like Effect of Acute Restraint Stress via CB1 Receptors

Arthur A Coelho; Carla Vila-Verde; Ariandra G Sartim; Daniela L Uliana; Laura A Braga; Francisco S Guimarães; Sabrina F Lisboa

doi:10.3389/fpsyt.2022.923177

Inducible Nitric Oxide Synthase Inhibition in the Medial Prefrontal Cortex Attenuates the Anxiogenic-Like Effect of Acute Restraint Stress via CB₁ Receptors

Front Psychiatry. 2022 Jul 14:13:923177. doi: 10.3389/fpsyt.2022.923177. eCollection 2022.

Authors

Arthur A Coelho^{1

2}, Carla Vila-Verde¹, Ariandra G Sartim², Daniela L Uliana^{1

3}, Laura A Braga¹, Francisco S Guimarães¹, Sabrina F Lisboa^{1

2}

Affiliations

¹ Pharmacology Department, Ribeirão Preto Medical School-University of São Paulo, São Paulo, Brazil.
² Biomolecular Sciences Department, School of Pharmaceutical Sciences of Ribeirão Preto-University of São Paulo, São Paulo, Brazil.
³ Departments of Neuroscience, Psychiatry and Psychology, University of Pittsburgh, Pittsburgh, PA, United States.

Abstract

Stress exposure can result in several proinflammatory alterations in the brain, including overexpression of the inducible isoform of nitric oxide synthase (iNOS) in the medial prefrontal cortex (mPFC). These changes may be involved in the development of many psychiatric conditions. However, it is unknown if iNOS in mPFC plays a significant role in stress-induced behavioral changes. The endocannabinoid (ECB) system is also influenced by stress. Its activation seems to be a counter regulatory mechanism to prevent or decrease the stress-mediated neuroinflammatory consequences. However, it is unclear if the ECB system and iNOS interact to influence stress consequences. This study aimed to test the hypothesis that the anti-stress effect of iNOS inhibition in mPFC involves the local ECB system, particularly the CB₁ cannabinoid receptors. Male Wistar rats with guide cannula aimed at the mPFC were submitted to acute restraint stress (RS) for 2 h. In the following morning, rats received bilateral microinjections of vehicle, AM251 (CB₁ antagonist; 100 pmol), and/or 1400W (iNOS selective inhibitor; 10^-4, 10^-3, or 10^-2 nmol) into the prelimbic area of mPFC (PL-mPFC) before being tested in the elevated plus-maze (EPM). iNOS inhibition by 1400W prevented the anxiogenic-like effect observed in animals submitted to RS. The drug did not promote behavior changes in naive animals, demonstrating a stress-dependent effect. The 1400W-anti-stress effect was prevented by local pretreatment with AM251. Our data suggest that iNOS inhibition may facilitate the local endocannabinoid signaling, attenuating stress effects.

Keywords: CB1 receptor; anxiety; iNOS; medial prefrontal cortex; stress.