Name: Rafaella Vila Real Barbosa
Type: MSc dissertation
Publication date: 19/08/2015
Advisor:

Namesort descending Role
Athelson Stefanon Bittencourt Advisor *

Examining board:

Namesort descending Role
Ana Paula Santana de Vasconcellos Bittencourt Co advisor *
Athelson Stefanon Bittencourt Advisor *
Jeyce Willig Quintino dos Santos External Examiner *
Vanessa Beijamini Harres Internal Examiner *

Summary: Panic Disorder (PD) is a common mental disorder that affects up to 5% of the population at some point in life and is characterized by the presence of recurrent panic attacks (AP). It is a psychopathology that may be affected by sleep deprivation (PS), relation that is still poorly understood. In this context, experimental models of AP and PS are useful tools in investigating this possible correlation, especially motivated by the growing of deprivation of sleep, which has become increasingly common in modern society. This study evaluated the effects of paradoxical sleep deprivation (PSP) in the thresholds of defensive behaviors induced by intracranial stimulation (EI) of MCPD and CS in rats, which is an experimental model of AP, as well as verified the influence of corticosterone on these thresholds. 160 male Wistar rats were used (300g), organized into 4 groups of 40 animals each, as follows: control group (CTR) submitted to EI, but no PSP; Deprivation group (PRV), submitted to EI and sleep deprived for 96 hours; Deprivation Group + corticosterone synthesis inhibition (PRB), undergoing treatment with metyrapone, EI, and sleep deprived for 96 hours, and the control group + corticosterone synthesis inhibition (CTB), undergoing treatment with metyrapone and EI, but without sleep deprivation. After 10 days of intracranial surgical implant of electrode in MCPD, the animals underwent 5 stimulation sessions, as follows: 1st (TRI) considered as a screening session - immediately before the deprivation, 2nd (P48) after 48 hours of deprivation, 3rd (P96) after 96 hours of deprivation, 4th (R48) 48 hours after the end of deprivation, and 5th (R96) after 96 hours of withdrawal of deprivation. The thresholds of the individual curves obtained for defense responses in the various stimulation sessions of CS and MCPD (TRI, P48, P96, R48 and R96) of the rats were compared, as well as a given threshold response curves in different groups (CTR, PRV, CTB and PRB). Furthermore, the levels of corticosterone (CORT) were measured in different sessions of EI and compared in the same group, as well as between the different groups. In the CTR group, all behaviors were equal in all sessions when compared to the TRI, however, in deprived animals (PRV), the threshold for galloping (GLP) was significantly reduced in R48 and R96, without changes in other behaviors. In contrast, in the xxi PRB group, Trotting (TRT) increased from P48, while the GLP has not changed in any EI session. Comparing the groups, Jumping (SLT), Micturation (MIC), Exophthalmos (EXO), Immobility (IMO), Defecation (DEF), Trotting (TRT) and Galloping (GLP), were not altered in function of CORT levels produced due PSP, suggesting that corticosterone does not influence the characteristic defensive behaviors induced by electrical stimulation of MCPD and CS. In addition, these results suggest that the delayed effect of the PSP on the GLP thresholds is possibly due to time-dependent neurochemical mechanisms.

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