Browsing by Subject "Habituation"

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    Dopaminergic Modulation of Forced Running Performance in Adolescent Rats: Role of Striatal D1 and Extra-striatal D2 Dopamine Receptors
    (Springer, 2021-01-04) Toval, Angel; Garrigos, Daniel; Kutsenko, Yevenhiy; Morales-Delgado, Nicanor; Tseng, Kuei I.; Ferrán Bertone, José Luis; Ribeiro do Couto, Bruno; Popovic Popovic, Miroljub; Anatomía Humana y Psicobiología
    Improving exercise capacity during adolescence impacts positively on cognitive and motor functions. However, the neural mechanisms contributing to enhance physical performance during this sensitive period remain poorly understood. Such knowledge could help to optimize exercise programs and promote a healthy physical and cognitive development in youth athletes. The central dopamine system is of great interest because of its role in regulating motor behavior through the activation of D1 and D2 receptors. Thus, the aim of the present study is to determine whether D1 or D2 receptor signaling contributes to modulate the exercise capacity during adolescence and if this modulation takes place through the striatum. To test this, we used a rodent model of forced running wheel that we implemented recently to assess the exercise capacity. Briefly, rats were exposed to an 8-day period of habituation in the running wheel before assessing their locomotor performance in response to an incremental exercise test, in which the speed was gradually increased until exhaustion. We found that systemic administration of D1-like (SCH23390) and/or D2-like (raclopride) receptor antagonists prior to the incremental test reduced the duration of forced running in a dose-dependent manner. Similarly, locomotor activity in the open field was decreased by the dopamine antagonists. Interestingly, this was not the case following intrastriatal infusion of an effective dose of SCH23390, which decreased motor performance during the incremental test without disrupting the behavioral response in the open field. Surprisingly, intrastriatal delivery of raclopride failed to impact the duration of forced running. Altogether, these results indicate that the level of locomotor response to incremental loads of forced running in adolescent rats is dopamine dependent and mechanistically linked to the activation of striatal D1 and extra-striatal D2 receptors.
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    The diurnal variation of open-field habituation in rats
    (Elsevier, 2020-06-30) Morales-Delgado, Nicanor; Caballero Bleda, María; Popovic, Natalija; Cruz Sánchez, Ernesto de la; Popovic Popovic, Miroljub; Poveda, Clara María; Anatomía Humana y Psicobiología
    The present study aimed to establish the effect of time of the day on habituation in the open-field test, one of the most elementary forms of non-associative hippocampal-dependent learning. Open-field test was performed in young adult male Wistar rats at the beginning (08:30−10:00 h; defined as Zeitgeber time (ZT) ZT0.5−2), mid-time (13:00−14:30 h, ZT5−6.5) and at the end (18:30−20:00 h, ZT10.5−12) of the light period. Our results revealed that in the acquisition trial there were no significant differences among the six parameters recorded through tested periods. In contrast, the level of habituation in the ambulation and rearing rose as followed: ZT0.5−2 < ZT10.5−12 < ZT5−6.5. In both trials, the principal component analysis highlights two components: component 1 was mainly loaded by ambulation in the outer and inner area, rearing and freezing behaviors, whereas component 2 was mostly loaded on grooming activity and defecation. The correlation between parameters varied across the period of day and trial. Animals that expressed a higher level of grooming, defecation (ZT5−6.5) and freezing behavior (ZT0.5−2 and ZT5−6.5) at acquisition trial habituated better on those parameters on the retention trial. In conclusion, habituation outcomes to the open-field test and correlation between tested parameters highly depend on daytime.
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    Verapamil parameter- and dose-dependently impairs memory consolidation in open field habituation task in rats
    (Frontiers Media, 2017-01-10) Giménez de Béjar, Verónica; Caballero Bleda, María; Popovic, Natalija; Popovic Popovic, Miroljub; Anatomía Humana y Psicobiología
    The purpose of the present study was to examine the effects of the phenylalkylamine class of the L-type voltage-dependent calcium channel antagonist, verapamil (1.0, 2.5, 5.0, or 10 mg/kg i.p.), administered immediately after the acquisition task, on memory consolidation of the open field habituation task, in male Wistar rats. On the 48 h retested trial, all tested parameters (ambulation in the side wall and in the central areas, number of rearing, time spent grooming and defecation rate) significantly decreased in the saline treated animals. A significant decrease of rearing was observed in all verapamil treated groups. On the retention day, the ambulation in the side wall and central areas significantly decreased in the animals treated with 1 mg/kg and 10 mg/kg of verapamil, while the time spent grooming and the defecation rate significantly decreased only in the group treated with 1 mg/kg of verapamil. According to the change ratio scores that correct the individual behavioral baseline differences during initial and final sessions, habituation deficit was found in animals treated with verapamil as follows: ambulation along the side wall area (1, 2.5, and 5 mg/kg), number of rearing (all used dose) and time spent grooming (2.5, 5, and 10 mg/kg). In conclusion, the present data suggest that the post-training administration of verapamil, parameter- and dose-dependently, impairs the habituation to a novel environment.