Gabriela V M Oliveira, Paloma M Hernandes, Fábio H Dos Santos, Victor P M N Soares, Luiz Luciano Falconi-Sobrinho, Norberto C Coimbra, Carsten T Wotjak, Rafael Carvalho Almada
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引用次数: 0
Abstract
Rationale: Despite the existing anatomical and physiological evidence pointing to the involvement of orexinergic projections from the lateral hypothalamus (LH) in regulating fear-related responses, little is known regarding the contribution of the orexin system in the prelimbic cortex (PL) on contextual fear.
Objectives: We investigated the role of orexin-A (OrxA) and orexin type 1 receptors (Orx1R) in the PL during the expression of contextual conditioned fear in mice.
Methods: Neural tract tracing of the LH-PL pathway and Orx1R immunoreactivity in the PL of C57BL/6 male mice were performed. In a pharmacological approach, the animals were treated with either the Orx1R selective antagonist SB 334,867 (3, 30, and 300 nM/0.1 µL) or OrxA (28, 70, and 140 pmol/0.1 µL) in the PL before the test session of contextual fear conditioning.
Results: Neural tract tracing deposits in the LH showed some perikarya, mainly axons and terminal buttons in the PL, suggesting LH-PL reciprocate pathways. Furthermore, we showed a profuse network comprised of Orx1R-labeled thin varicose fibers widely distributed in the same field of LH-PL pathways projection. The selective blockade of Orx1R with SB 334,867 at 30 and 300 nM in the PL caused a decrease in freezing response, whereas the treatment with OrxA at 140 pmol promoted an increase in freezing response.
Conclusion: In summary, these data confirmed an anatomical link between LH and PL, established the presence of Orx1R in the PL, and a modulatory role of the orexin system in such structure, possibly mainly via Orx1R, during contextual fear conditioning.
期刊介绍：
Official Journal of the European Behavioural Pharmacology Society (EBPS)
Psychopharmacology is an international journal that covers the broad topic of elucidating mechanisms by which drugs affect behavior. The scope of the journal encompasses the following fields:
Human Psychopharmacology: Experimental
This section includes manuscripts describing the effects of drugs on mood, behavior, cognition and physiology in humans. The journal encourages submissions that involve brain imaging, genetics, neuroendocrinology, and developmental topics. Usually manuscripts in this section describe studies conducted under controlled conditions, but occasionally descriptive or observational studies are also considered.
Human Psychopharmacology: Clinical and Translational
This section comprises studies addressing the broad intersection of drugs and psychiatric illness. This includes not only clinical trials and studies of drug usage and metabolism, drug surveillance, and pharmacoepidemiology, but also work utilizing the entire range of clinically relevant methodologies, including neuroimaging, pharmacogenetics, cognitive science, biomarkers, and others. Work directed toward the translation of preclinical to clinical knowledge is especially encouraged. The key feature of submissions to this section is that they involve a focus on clinical aspects.
Preclinical psychopharmacology: Behavioral and Neural
This section considers reports on the effects of compounds with defined chemical structures on any aspect of behavior, in particular when correlated with neurochemical effects, in species other than humans. Manuscripts containing neuroscientific techniques in combination with behavior are welcome. We encourage reports of studies that provide insight into the mechanisms of drug action, at the behavioral and molecular levels.
Preclinical Psychopharmacology: Translational
This section considers manuscripts that enhance the confidence in a central mechanism that could be of therapeutic value for psychiatric or neurological patients, using disease-relevant preclinical models and tests, or that report on preclinical manipulations and challenges that have the potential to be translated to the clinic. Studies aiming at the refinement of preclinical models based upon clinical findings (back-translation) will also be considered. The journal particularly encourages submissions that integrate measures of target tissue exposure, activity on the molecular target and/or modulation of the targeted biochemical pathways.
Preclinical Psychopharmacology: Molecular, Genetic and Epigenetic
This section focuses on the molecular and cellular actions of neuropharmacological agents / drugs, and the identification / validation of drug targets affecting the CNS in health and disease. We particularly encourage studies that provide insight into the mechanisms of drug action at the molecular level. Manuscripts containing evidence for genetic or epigenetic effects on neurochemistry or behavior are welcome.
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