Serotonergic activity in ventral hippocampus on 5th2a receptors in the regulation of the defensive behaviours related to generalized anxiety and panic

• Grant number: 16/16015-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): November 01, 2016
• Effective date (End): October 31, 2017
• Field of knowledge: Biological Sciences - Pharmacology - Neuropsychopharmacology
• Principal Investigator: Telma Goncalves Carneiro Spera de Andrade
• Grantee: Paloma Molina Hernandes
• Host Institution: Faculdade de Ciências e Letras (FCL-ASSIS). Universidade Estadual Paulista (UNESP). Campus de Assis. Assis , SP, Brazil

Abstract

The serotoninergic activity on 5-HT1A receptors in the ventral hippocampus (VH) in the regulation of different types of anxiety is not well known. A previous study in our laboratory using the Elevated T Maze (ETM) showed that the activation of receptors 5-HT1A in VH decreases the avoidance behavior of the animals without affecting the escape responses, similar to what was observed as a result of midazolam action on receptors GABAA, indicating involvement of receptors in the regulation of Generalized Anxiety Disorder, but not panic disorder. However, although there was no direct effect of serotonin and not evaluated the activation of other subtypes of serotoninergic receptors 5-HT2A type have been identified in this region of the hippocampus on the manifestation of these subtypes of anxiety through the ETM. Thus, in order to investigate these aspects, male Wistar rats will undergo stereotactic surgery to implant cannulas, enabling access to the Ventral hippocampus bilaterally. For habituation of animals to the researcher, the 4th and 5th postoperative day, the animals will be submitted to the "handling" (5 minutes/day). On the 6th day after the surgery will be confined in one of the open arms of the Elevated T Maze for 30 minutes. Twenty-four hours after the confinement will undergo behavioral assessment in the Elevated T Maze and sequence in the Arena (on the 7th day after stereotactic surgery), immediately after the microinjection bilaterally in the hippocampus Ventral. The study will be developed in two steps, and in each there will be a control group with saline microinjection in VH. Each group will consist of a minimum of 10 animals. Step 1 - microinjection VH Serotonin (4, 8 ou 16 nmol - 5-Hydroxytryptamine hydrochloride); Step 2 - microinjection VH specific agonist of 5-HT2A (DOI 4, 8 e 16 nmol - R(-)-2,5-dimethoxy-4-iodoamphetamine). The results will be submitted to Anova of the repeated measures, evaluating separately the avoidances and escapes on ETM, comparing treatments (solutions and doses used) and reexposition in each arm, at each step of the study separately. The number of squares covered in the arena, as the index of motor activity of animals will be evaluated by ANOVA one way.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

HERNANDES, PALOMA MOLINA; BATISTELA, MATHEUS FITIPALDI; VILELA-COSTA, HELOISA HELENA; SANT `ANA, ANA BEATRIZ; KUMPEL, VINICIUS DIAS; TIRAPELLE, MARIANE CARIATI; BOM, ARIELA DE OLIVEIRA PEDRO; DE ANDRADE, TELMA GONCALVES CARNEIRO SPERA; ZANGROSSI JR, HELIO. Role of 5-HT1A receptors in the ventral hippocampus in the regulation of anxiety- and panic-related defensive behaviors in rats. Behavioural Brain Research, v. 408, JUN 25 2021. (16/16015-5, 17/18437-7)