PhD Scientific Days 2022

Neurosciences I. (Poster discussion will take place in the Aula during the Coffee Break)

Cognitive Characterization of the Scopolamine-induced Dementia Model in Experienced Rats

Text of the abstract

Scopolamine is an anticholinergic compound widely used as a pharmacological model of cognitive impairment. The drug is typically applied in single dose and in naïve or freshly taught animals.
The objective of this study was to examine the effects of repeated scopolamine treatment on several cognitive functions in young, experienced Long-Evans rats and to see to what extent donepezil can block these actions.
We used 35 male rats with 11 weeks learning experience in assays of five different cognitive domains: 5-choice serial reaction time task (5CSRTT, attention), Morris water maze (MWM, spatial learning), pot jumping test (PJ, motor learning), pairwise discrimination (PWD, visual learning) and cooperation test (social learning). After baseline measurements rats were randomly assigned into three treatment groups: saline (n=11), scopolamine (0.3 mg/kg ip., n=12), and scopolamine+donepezil (3 mg/kg ip., n=12). The former two groups received their appropriate treatment for 20 days, while the third group was injected scopolamine for 20 days and donepezil in the second 10 days of this period. The treatment period was followed by an 11-day wash-out phase. Cognitive performance of the rats was tested in the above assays on 6 occasions, twice during each phase of the study (scopolamine only, scopolamine+donepezil, wash-out). Drug injections were carried out 30 min before the learning tests.

Scopolamine treatment caused significant impairments in the 5CSRTT, cooperation and PJ assays but not in the MWM and the PWD tests. Donepezil treatment did not ameliorate the learning performance deficit in any of the tests. After discontinuation of the treatments, all groups showed similar performance to their baseline levels.
Based on our results, scopolamine could not induce lasting changes in the functioning of cognitive neural networks, therefore it may not be an appropriate model for testing potential antidementia drugs.
The work was funded by the National Excellence Program of Hungary within the framework of the Hungarian National Brain Research Program (NAP 2.0), contract# 2017-1.2.1-NKP-2017- 00002, the support provided by the Ministry of Innovation and Technology of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-EGA-25 funding scheme and the Új Nemzeti Kiválóság Program ÚNKP-21-3-SE-II.