Effects of cannabidiol on behavioral and plastic consequences promoted by stress

• Grant number: 07/07070-3
• Support Opportunities: Scholarships in Brazil - Doctorate
• Effective date (Start): March 01, 2008
• Effective date (End): July 31, 2011
• Field of knowledge: Biological Sciences - Pharmacology - Neuropsychopharmacology
• Principal Investigator: Francisco Silveira Guimaraes
• Grantee: Alline Cristina de Campos
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 07/03685-3 - Typical and atypical neurotransmitters in neuropsychiatric disorders, AP.TEM

Abstract

Posttraumatic stress disorder (PTSD) is an incapacitating chronic syndrome that reflects cognitive, emotional, and physiological processing disorders that follows an initial reaction to a traumatic experience. Limbic structures such as the amigdala, prefrontal cortex, hippocampus and periaqueductal grey could be involved with aversive memory processing and defensive behavioral expressions related to PTSD. Serotonin (mainly 5HT1A signaling) and endocannabinoids seems to decrease defensive behaviors and several brain structures. Moreover, CB1 receptors could participate in aversive memories extinction. Cannabidiol (CBD), a nonpsychotomimetic constituent of Cannabis sativa plant, produces anxiolytic-like effects in animal models and humans. Although its mechanisms of action are not clear, CBD could facilitate the neurotransmission mediated by 5HT1A and CB1 receptors. However the effects of CBD in PTSD models have not been investigated yet. Thus, the aim of this study is to investigate CBD effects on behavioral, morphologic and molecular changes in rats submitted to a PTSD model. As specific objectives we will investigate: 1. if systemic administration of CBD will be able to attenuate long lasting defensive behaviors of rats exposed to a live cat; 2. if these effects involve activation of 5HT1A or CB1 receptors; 3. if the systemic effects of CBD can also be observe after injections in brain structures related to PSTD; 4. if the CBD treatment decrease the plastic changes produced by predator exposure. (AU)