Estudos imunoistoquímicos dos sistemas de alarme de predação e sufocamento e sua relação com pânicos respiratórios e não respirtórios.
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Data
2016-06-27
Autores
Müller, Cláudia Janaina Torres
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Universidade Federal do Espírito Santo
Resumo
The panic disorder (PD) is a anxiety disorders relatively common, with a prevalence estimated between 1% and 3%. The main symptom is panic attack (PA) spontaneous, which can occur several times a day or only a few times per year. Of the main hypotheses about the neural basis of PD, two are worth mentioning.The first, proposed by Deakin & Graeff (1991), postulates that the serotonergic system evolved as a specialized aversive situations control system. Additionally, it postulates that the periaqueductal gray matter (PAG) is a center of coordination of defensive reflexes to predators or proximal noxious stimuli, whose spontaneous activation triggers the AP. The second is the hypothesis of "false alarm suffocation" proposed by Klein (1993). According to this hypothesis AP as either spontaneous caused by lactate infusion or inhalation lower CO2 concentrations (5-7%) are caused by improper firing of a hypothetical suffocation alarm system. These hypotheses are supported by epidemiological evidence to suggest the existence of AP both respiratory and non-respiratory. On the other hand, several studies indicate that traumatic events in childhood predispose the individual to the development of anxiety and depressive disorders in adulthood, particularly of PA. Therefore, the present study compared the neural systems activated in both respiratory and nonrespiratory models panic to administration of KCN and exposure to cat, respectively. Additionally, checking the effects of neonatal social isolation (NSI) we saw it on the behaviors and systems activated in adult rats exposed to a cat. In a first study, we examined whether NSI increases the Fos-like immunoreactivity (FLI) and the behaviors of defense rats exposed to cat in adulthood. The second study, examined the effects of a low dose of potassium 6 cyanide (KCN, 40 µg) or brief exposure to 13% CO2 (2 min), or combination of stimuli (CO2 / KCN), in the FLI. The behavioral effects of microinjection of KCN into the PAG were also examined. Data showed that both submited to NSI and CTR rats showed innate fear responses, such as freezing, avoidance and risk assessment behaviors. In addition, the groups show significant increases in FLI in areas traditionally related to defense to predators, namely, MCPA dorsolateral, dorsal pre-mammillary nucleus and anterior hypothalamus. However, the INS rats showed IRF more pronounced than the CTR.The exposed to cat increased c-Fos density in defense related area (MCPAdl, PMd and AHN). The NSI group showed higher expression c-Fos in all area examined. Notably, data suggest that the NSI promotes a life-long facilitation of circuits activated by predator. These data suggest that the NSI promotes a perennial awareness related to predation circuitry, adding evidence that the separation stress in childhood predisposes the individual to the AP development in adulthood. The results of the second study showed that whereas the KCN injection elicited escape in all tested rats, the KCN microinjection into the PAG was ineffective. Additionally, while the núcleo do trato solitário (NTS) was activated in group CO2/SAL and CO2/KCN the laterodorsal tegmental nucleus (LDTg) was activated by all treatments. Surprisingly, the KCN only produced activations rostrolateral and caudoventrolateral PAG (Although these data suggest that suffocation alarm system is composed by LDTg and the rostrolateral and caudoventrolateral regions of the PAG, the latter areas are specifically activated in rats that have escape responses only to KCN. Therefore, they are prime candidates to suffocation alarm system.
Descrição
Palavras-chave
periaqueductal gray matter , immunoreactivity , panic Attack , phobia , suffocation alarm system , exposure to a cat , separation anxiety in childhood, , separation stress in childhood , Matéria cinzenta periaquedutal , Imunoreatividade , c-Fos , Pânico , Fobia , Alarme de sufocamento , Ansiedade de Separação , Estresse na Infância
Citação
MULLER, Cláudia Janaina Torres. Estudos imunoistoquímicos dos sistemas de alarme de predação e sufocamento e sua relação com pânicos respiratórios e não respirtórios. 2016. Tese (Doutorado em Ciências Fisiológicas) - Universidade Federal do Espírito Santo, Centro de Ciências da Saúde, Vitória, 2016.