Fatores interferentes na indução da atividade rotacional induzida pelo teste de motricidade sobre grade em modelo animal da doença de Parkinson

AUTOR(ES)

Camilla Lazzaretti

FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

2011

RESUMO

Parkinson s disease (PD) is a progressive neurodegenerative disorder that affects 1% of the population above 55 years. In a previous work, it was shown that the footfault test is a tool for screening highly lesioned rats in modeling for PD using the toxin 6-hydroxydopamine (6-OHDA), which is widely used, by observing whether animals present or not context-induced ipsilateral rotational activity (CIIRA). However, it is not known whether CIIRA may change because of variations in the apparatus ¿ such as in height or in surface texture, or in placing a surrounding wall - or of other differences, such as varying the 6-OHDA infusion site or the behavioral protocols, by including other testing sessions or applying a drug before testing. Male Wistar rats (110 days old) received 6-OHDA infusions into either the striatum (3.3 ¿g/¿L, 6 ¿L), the MFB (3 ¿g/¿L, 5,5 ¿L) or the substantia nigra (0, 3, 6, 12¿g/¿L, 4 ¿L), and were submitted to the footfault test 22 days later. In the case of animals that received infusions into the MFB, the footfault test varied in height (8 or 76.5 cm), surface (presence or not of a transparent glass on the grid), edge (presence or not of a surrounding wall 30 or 60 cm from the center). One cohort of these animals had a previous testing session 7 days before surgery and another received either diazepam (2 mg/kg, i.p.) or saline 30 min before testing. Our results show that a surrounding wall eliminates CIIRA (Fisher s exact test, p = 0.016), even though it was not possible to specify this effect concerning the wall distance from the center (30 or 60 cm; Fisher s exact test, p= 0.066 and 0.070, respectively). There was no difference by varying the height or the surface of the apparatus (Fisher s exact test, p =0.424 and 1.000, respectively) or by administrating diazepam before testing (Fisher s exact test, p =0, 648). It was observed that animals who received infusions into either the striatum (Fisher s exact test, p = 0.016) or the substantia nigra (Spearman correlation, ñ= 0,53, p=0,003) presented CIIRA in the footfault test. Our results suggest that CIIRA in the footfault is a robust effect in PD animal models considering the 6-OHDA infusion site and height of TMG, or if a transparent glass is placed on the grid. The presence of a surrounding wall eliminates the rotational activity, indicating that the possibility of presenting a tigmotaxic behavior interfere in this process. However, diazepam was not effective, indicating that the role of anxiety in this process requires further studies. Thus, we show the importance of tigmotaxic behavior as a main factor of rotational activity induced by the footfault test, and probably for understanding the underlying mechanisms and for the continuity of the studies using the apparatus.

ASSUNTO(S)

doença de parkinson teste de esforço atividade motora oxidopamina modelos animais

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