title: Immobility behavior during the forced swim test correlates with BNDF levels in the frontal cortex, but not with cognitive impairments.
abstract: The forced swim test (FST) is widely used to evaluate the antidepressant-like activity of compounds and is sensitive to stimuli that cause depression-like behaviors in rodents. The immobility behavior observed during the test has been considered to represent behavioral despair. In addition, some studies suggest that the FST impairs rats' performance on cognitive tests, but these findings have rarely been explored. Thus, we investigated the effects of the FST on behavioral tests related to neuropsychiatric diseases that involve different cognitive components: novel object recognition (NOR), the object location test (OLT) and prepulse inhibition (PPI). Brain-derived neurotrophic factor (BDNF) levels in the frontal cortex and hippocampus were evaluated. The rats were forced to swim twice (15-min session followed by a 5-min session 24h later) and underwent cognitive tests 24h after the last swimming exposure. The FST impaired the rats' performance on the OLT and reduced the PPI and acoustic startle responses, whereas the NOR was not affected. The cognitive impairments were not correlated with an immobility behavior profile, but a significant negative correlation between the frontal BDNF levels and immobility behavior was identified. These findings suggest a protective role of BDNF against behavioral despair and demonstrate a deleterious effect of the FST on spatial memory and pre-attentive processes, which point to the FST as a tool to induce cognitive impairments analogous to those observed in depression and in other neuropsychiatric disorders.
authors.affiliation: Graduate Studies Program in Neurosciences, Federal University of Rio Grande do Sul, 500 Sarmento Leite Street, ZIP code 90046-900 Porto Alegre, RS, Brazil.
authors.forename: Milene
authors.initials: M
authors.lastname: Borsoi
authors.affiliation: Graduate Studies Program in Pharmaceutical Sciences, Federal University of Rio Grande do Sul, 2752 Ipiranga Avenue, ZIP code 90610-000 Porto Alegre, RS, Brazil.
authors.forename: Camila Boque
authors.initials: CB
authors.lastname: Antonio
authors.affiliation: Graduate Studies Program in Pharmaceutical Sciences, Federal University of Rio Grande do Sul, 2752 Ipiranga Avenue, ZIP code 90610-000 Porto Alegre, RS, Brazil.
authors.forename: Alice Fialho
authors.initials: AF
authors.lastname: Viana
authors.affiliation: Graduate Studies Program in Biochemistry, Federal University of Rio Grande do Sul, 2600 Ramiro Barcelos Street, ZIP code 90035-003 Porto Alegre, RS, Brazil.
authors.forename: Patrícia
authors.initials: P
authors.lastname: Nardin
authors.affiliation: Graduate Studies Program in Neurosciences, Federal University of Rio Grande do Sul, 500 Sarmento Leite Street, ZIP code 90046-900 Porto Alegre, RS, Brazil; Graduate Studies Program in Biochemistry, Federal University of Rio Grande do Sul, 2600 Ramiro Barcelos Street, ZIP code 90035-003 Porto Alegre, RS, Brazil.
authors.forename: Carlos-Alberto
authors.initials: CA
authors.lastname: Gonçalves
authors.affiliation: Graduate Studies Program in Neurosciences, Federal University of Rio Grande do Sul, 500 Sarmento Leite Street, ZIP code 90046-900 Porto Alegre, RS, Brazil; Graduate Studies Program in Pharmaceutical Sciences, Federal University of Rio Grande do Sul, 2752 Ipiranga Avenue, ZIP code 90610-000 Porto Alegre, RS, Brazil. Electronic address: stela.rates@ufrgs.br.
authors.forename: Stela Maris Kuze
authors.initials: SM
authors.lastname: Rates
mesh_terms: D000161:Acoustic Stimulation; D000162:Acoustics; D000704:Analysis of Variance; D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism*; D003072:Cognition Disorders / Q000209:etiology*; D005106:Exploratory Behavior / Q000502:physiology; D046352:Freezing Reaction, Cataleptic / Q000502:physiology*; D005625:Frontal Lobe / Q000378:metabolism*; D008297:Male; D065808:Prepulse Inhibition / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D021641:Recognition, Psychology; D013223:Statistics as Topic; D013312:Stress, Physiological; D013550:Swimming / Q000523:psychology*; D013997:Time Factors
chemical_list: D019208:Brain-Derived Neurotrophic Factor
keywords: Acoustic startle response; Brain-derived neurotrophic factor; Forced swimming stress; Novel object recognition; Object location test; Prepulse inhibition