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Study of the involvement of the opioid system and the neural networks between medial hypothalamus and periaqueductal grey matter in antinociceptive processes induced by oriented escaped reactions evoked after chemical stimulation of the medial hypothalamus

Grant number: 09/01157-5
Support Opportunities:Scholarships in Brazil - Master
Effective date (Start): March 01, 2010
Effective date (End): October 31, 2010
Field of knowledge:Biological Sciences - Pharmacology - Neuropsychopharmacology
Principal Investigator:Norberto Cysne Coimbra
Grantee:Maria Angelica Castiblanco Urbina
Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil


The electrical and chemical stimulation of some mesencephalic structures, such as periaqueductal gray matter, deep layers of superior colliculus and central nucleus of the inferior colliculus induce explosive defensive behaviors, associated to fear and similar to panic disorder in humans. When the stimulation is made into the medial hypothalamus, the defensive response is characterized by a high or moderate oriented escape reaction. Studies showed that, the antinocioceptive processes are modulated by different opioids and non-opioids mediators in the mesencephalic mesencephalic structures and nuclei of the pain inhibitory endogenous system and hypothalamic complex, for wich are destined inhibitory GABAergic projections. The objective of the present study is to establish the connections between the ventro-medial and dorso-medial hypothalamus with the periaqueductal gray matter and the pain inhibitory endogenous system, through an anatomic study with iontophoretic microinjections of anterograde and retrograde neurotracer, biodextran marked with texas red or fluoresceine, in each hypothalamic nucleus studied in this project. Another study will be made on the effect of the neurotoxic lesion with chloride cobalt into the dorsal periaqueductal gray matter, This structure may have direct or indirect connections with the ventro-medial and dorso-medial hypothalamus and has a role in the analgesia induced by evoked fear for chemical stimulation into ventro-medial and dorso-medial hypothalamus. In this study, the effects of pre- treatment with microinjections with opioids antagonists into the periaqueductal gray matter will be determined, a nucleus rich in encefaline and beta-endorfine, this nucleus possibly has direct connections with ventro-medial and dorso-medial hypothalamus. Thus, an evaluation of the involvement of the neural networks imply in the pain control during the organized antinocioception will be realized. (AU)

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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)
URIBE-MARINO, ANDRES; FRANCISCO, AUDREY; CASTIBLANCO-URBINA, MARIA ANGELICA; TWARDOWSCHY, ANDRE; SALGADO-ROHNER, CARLOS JOSE; CRIPPA, JOSE ALEXANDRE S.; CECILIO HALLAK, JAIME EDUARDO; ZUARDI, ANTONIO WALDO; COIMBRA, NORBERTO CYSNE. Anti-Aversive Effects of Cannabidiol on Innate Fear-Induced Behaviors Evoked by an Ethological Model of Panic Attacks Based on a Prey vs the Wild Snake Epicrates cenchria crassus Confrontation Paradigm. NEUROPSYCHOPHARMACOLOGY, v. 37, n. 2, p. 412-421, . (09/01153-0, 08/08955-1, 08/00531-8, 09/01157-5)

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