Serotonin actions within the prelimbic cortex induce anxiolysis mediated by serotonin 1a receptors

Author(s)

Yamashita, Paula S. M. ^{[1, 2, 3]} ; Rosa, Daiane S. ^[4] ; Lowry, Christopher A. ^{[1, 2]} ; Zangrossi, Jr., Helio ^{[4, 3]}

Affiliation

^[1] Univ Colorado, Dept Integrat Physiol, Boulder, CO 80309 - USA

^[2] Univ Colorado, Ctr Neurosci, Boulder, CO 80309 - USA

^[3] Univ Sao Paulo, Dept Pharmacol, Ribeirao Preto Med Sch, 3900 Bandeirantes Ave, BR-14049900 Ribeirao Preto, SP - Brazil

^[4] Univ Sao Paulo, Dept Neurosci & Behav Sci, Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: JOURNAL OF PSYCHOPHARMACOLOGY; v. 33, n. 1, p. 3-11, JAN 2019.
• Web of Science Citations: 1

Abstract

Background: Serotonin plays an important role in the regulation of anxiety, acting through complex modulatory mechanisms within distinct brain structures. Serotonin can act through complex negative feedback mechanisms controlling the neuronal activity of serotonergic circuits and downstream physiologic and behavioral responses. Administration of serotonin or the serotonin 1A receptor agonist, (+/-)-8-hydroxy-2-(dipropylamino)tetralin (8-OH-DPAT), into the prefrontal cortex, inhibits anxiety-like responses. The prelimbic area of the prefrontal cortex regulates serotonergic neurons within the dorsal raphe nucleus and is involved in modulating anxiety-like behavioral responses. Aims: This study aimed to investigate the serotonergic role within the prelimbic area on anxiety- and panic-related defensive behavioral responses. Methods: We investigated the effects of serotonin within the prelimbic area on inhibitory avoidance and escape behaviors in the elevated T-maze. We also extended the investigation to serotonin 1A, 2A, and 2C receptors. Results: Intra-prelimbic area injection of serotonin or 8-OH-DPAT induced anxiolytic effects without affecting escape behaviors. Previous administration of the serotonin 1A receptor antagonist, WAY-100635, into the prelimbic area counteracted the anxiolytic effects of serotonin. Neither the serotonin 2A nor the serotonin 2C receptor preferential agonists, (+/-)-2,5-dimethoxy-4-iodoamphetamine (DOI) and 6-chloro-2-(1-piperazinyl) pyrazine (MK-212), respectively, affected behavioral responses in the elevated T-maze. Conclusion: Facilitation of serotonergic signaling within the prelimbic area of rats induced an anxiolytic effect in the elevated T-maze test, which was mediated by local serotonin 1A receptors. This inhibition of anxiety-like defensive behavioral responses may be mediated by prelimbic area projections to neural systems controlling anxiety, such as the dorsal raphe nucleus or basolateral amygdala. (AU)

• FAPESP's process: 10/07544-8 - Involvement of the pathway prefrontal cortex - dorsal raphe nucleus - dorsal periaqueductal gray in the regulation of defensive responses associated to the anxiety and to the panic
• Grantee: Paula Shimene de Melo Yamashita
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 12/17626-7 - Cellular and molecular mechanisms involved in the role of atypical neurotransmitters in neuropsychiatric disorders
• Grantee: Francisco Silveira Guimaraes
• Support Opportunities: Research Projects - Thematic Grants