ABSTRACT
RATIONALE: The production of unconditioned defensive behaviors has been related to the amygdala, a key component of the encephalic aversion system. Microinjection of the neuropeptide substance P (SP) in the amygdala elicits defensive behaviors via the activation of type 1 neurokinin (NK-1) receptors. However, no studies have investigated whether intra-amygdala SP/NK-1 mechanisms can elicit other types of defensive responses, such as antinociception and ultrasonic vocalizations (USVs). METHODS: The present study investigated the effects of SP-induced activation of the neurokininergic system in three main nuclei of the amygdala-basolateral (BLA), central (CeA), and medial (MeA) nuclei-in rats that were subjected to the elevated plus maze (EPM), tail-flick test, and USV recording. The effects of SP in these amygdaloid nuclei were challenged with combined injections of the NK-1 receptor antagonist spantide. RESULTS: The present study showed that SP injections in the CeA and MeA but not BLA exerted anxiogenic-like effects. In contrast to the CeA, the anxiogenic-like effects of SP in the MeA were not dependent on NK-1 mechanisms. In the tail-flick test, SP microinjections produced antinociceptive effects only in the MeA through NK-1 receptor activation. No USV emissions were detected after the SP microinjections. CONCLUSIONS: The present study showed that NK-1 receptors in the CeA and MeA but not BLA are involved in defensive reactions to conditions of fear. The present results may provide a better understanding of the neurochemical mediation of fear states.
Subject(s)
Amygdala/drug effects , Fear/drug effects , Fear/psychology , Neurokinin-1 Receptor Antagonists/pharmacology , Receptors, Neurokinin-1/metabolism , Substance P/antagonists & inhibitors , Substance P/pharmacology , Analgesics/pharmacology , Animals , Behavior, Animal/drug effects , Male , Maze Learning/drug effects , Microinjections , Rats , Substance P/administration & dosage , Substance P/analogs & derivatives , Vocalization, Animal/drug effectsABSTRACT
The substantia nigra pars reticulata (SNpr) is rich in γ-aminobutyric acid (GABA)-ergic neurons and connected to the mesencephalic tectum (MT) structures, such as the superior colliculus and dorsal periaqueductal gray matter. The SNpr presents a high density of cannabinoid receptors (CBRs), suggesting a possible regulatory role that is played by endocannabinoids (eCBs) in the ventral mesencephalon. The present study investigated the involvement of SNpr eCB mechanisms in nigrotectal pathways in the expression of defensive behavior associated with instinctive fear and panic reactions in mice that are confronted with the venomous Viperidae snake Bothrops alternatus. The localization of CB1 receptors (CB1RS) and synaptophysin glycoprotein in the SNpr was also evaluated. Administration of the GABAA receptor antagonist bicuculline in the MT increased defensive responses to the snake that are related to panic, such as freezing and non-oriented escape reactions, sometimes toward the snake itself. Mice that were pretreated with anandamide (5 or 50pmol) in the SNpr, followed by an injection of physiological saline or bicuculline in the MT, exhibited significant decreases in the expression of alertness, freezing, and escape responses. Immunofluorescence showed the presence of fibers that were rich in CB1RS and synaptophysin in the SNpr, indicating that these receptors appear to be located mainly in presynaptic terminals in the striatonigral pathway. These findings suggest that eCB mechanisms in the SNpr facilitate the activity of nigrotectal GABAergic pathways, modulating the activity of striatonigral links during the elaboration and organization of innate fear and panic-like responses in threatening situations.
Subject(s)
Endocannabinoids/metabolism , Fear/physiology , Pars Compacta/physiology , Signal Transduction/physiology , Tectum Mesencephali/metabolism , gamma-Aminobutyric Acid/metabolism , Animals , Arachidonic Acids/pharmacology , Bicuculline/pharmacology , Crotalid Venoms , Endocannabinoids/pharmacology , Escape Reaction/drug effects , Fear/drug effects , Fear/psychology , Functional Laterality , GABA-A Receptor Antagonists/pharmacology , Immobility Response, Tonic/drug effects , Immobility Response, Tonic/physiology , Male , Mice , Mice, Inbred C57BL , Neural Pathways/drug effects , Neural Pathways/physiology , Pars Compacta/drug effects , Polyunsaturated Alkamides/pharmacology , Receptor, Cannabinoid, CB1/metabolism , Signal Transduction/drug effects , Synaptophysin/metabolism , ViperidaeABSTRACT
Several lines of evidence indicate that the dorsal hippocampus (dH) and medial prefrontal cortex (mPFC) regulate contextual fear conditioning. The prelimbic (PrL), infralimbic (IL) and the anterior cingulate cortex (ACC) subregions of the mPFC likely play distinct roles in the expression of fear. Moreover, studies have highlighted the role of serotonin (5-hydroxytryptamine, 5-HT)- and γ-aminobutyric acid (GABA)-mediated mechanisms in the modulation of innate fear in the mPFC. The present study characterized dH-mPFC pathways and investigated the role of serotonergic and GABAergic mechanisms of the PrL, IL and ACC-area 1 (Cg1) in the elaboration of contextual fear conditioning using fear-potentiated startle (FPS) and freezing behavior in Rattus norvegicus. The results of neurotracing with microinjections of biotinylated dextran amine into the dH revealed a neural link of the dH with the PrL and ACC. Intra-PrL injections of the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) and the GABAA receptor-selective agonist muscimol reduced contextual FPS and freezing responses. Intra-Cg1 injections of muscimol but not 8-OH-DPAT decreased FPS and freezing responses. However, neither intra-IL injections of a 5-HT1A agonist nor of a GABAA agonist affected these defensive responses. Labeled neuronal fibers from the dH reached the superficial layers of the PrL cortex and spread to the inner layers of PrL and Cg1 cortices, supporting the pharmacological findings. The present results confirmed the involvement of PrL and Cg1 in the expression of FPS and freezing responses to aversive conditions. In addition, PrL serotoninergic mechanisms play a key role in contextual fear conditioning. This study suggests that PrL, IL and Cg1 distinctively contribute to the modulation of contextual fear conditioning.
Subject(s)
Conditioning, Psychological/drug effects , Fear/drug effects , GABA-A Receptor Agonists/pharmacology , Prefrontal Cortex/drug effects , Serotonin 5-HT1 Receptor Agonists/pharmacology , 8-Hydroxy-2-(di-n-propylamino)tetralin/pharmacology , Animals , Biotin/analogs & derivatives , Conditioning, Psychological/physiology , Dextrans , Fear/physiology , Freezing Reaction, Cataleptic/drug effects , Freezing Reaction, Cataleptic/physiology , Limbic Lobe/anatomy & histology , Limbic Lobe/drug effects , Limbic Lobe/physiology , Male , Muscimol/pharmacology , Neural Pathways/anatomy & histology , Neural Pathways/drug effects , Neural Pathways/physiology , Neuroanatomical Tract-Tracing Techniques , Neuronal Tract-Tracers , Prefrontal Cortex/anatomy & histology , Prefrontal Cortex/physiology , Rats, Wistar , Receptor, Serotonin, 5-HT1A/metabolism , Receptors, GABA-A/metabolism , Reflex, Startle/drug effects , Reflex, Startle/physiology , Serotonin/metabolism , gamma-Aminobutyric Acid/metabolismABSTRACT
El presente es un trabajo de revisión y puesta al día de la literatura respecto al tema de los movimientos anormales de etiología psicógeno. Se comunica un caso clínico de distonia psicógena clínicamente establecida, analizando su historia desde el punto de vista neurológico y psiquiátrico, fundamentos el diagnóstico positivo y analizando los diagnóstico diferentes. Concluimos en la necesidad del abordaje neuropsiquiátrico cuando se abordan pacientes que padecen movimientos anormales.
This document is a work revision and an update of the psychogenic etiology of movement disorders literature. A medical case of dystonia psychogenia clinically established is reported, the medical history is analyzed from a neurological and psychiatric perspective, the positive diagnosis is explained, and the different diagnosis analyzed. Finally, we conclude the necessity of neuropsychiatric treatment when those patients suffer movement disorders.
Subject(s)
Male , Female , Humans , Neuropsychiatry , Movement DisordersSubject(s)
Humans , Female , Pregnancy , Adult , Hyperemesis Gravidarum , Pregnancy Complications , VomitingSubject(s)
Humans , Female , Pregnancy , Adult , Hyperemesis Gravidarum , Pregnancy Complications , VomitingABSTRACT
La correcta aplicación de una toma de fórceps para abreviar el período expulsivo exige considerar una serie de variables que de no tenerse en cuenta puden convertir la maniobra en un fracaso y lejos de solucionar un problema, generar daño tanto a la madre como al recién nacido
Subject(s)
Humans , Female , Adult , Obstetrical Forceps , Labor, ObstetricABSTRACT
La correcta aplicación de una toma de fórceps para abreviar el período expulsivo exige considerar una serie de variables que de no tenerse en cuenta puden convertir la maniobra en un fracaso y lejos de solucionar un problema, generar daño tanto a la madre como al recién nacido
