engleski

Serotonin enhances cognitive performance: studies on Wistar-Zagreb 5HT rat

Serotonin (5HT) system plays an important role in processes of learning and memory, especially in consolidation of novel information into long-term memory. Previously, we have developed an animal model, Wistar-Zagreb 5HT rat, with constitutively altered both peripheral and central 5HT homeostasis. Two sublines of the model, developed by selective breeding toward peripheral 5HT parameters, are characterized by increased (high-5HT subline) or decreased (low-5HT subline) values of platelet 5HT level and transporter activity, as well as plasma free 5HT. Sublines also differ in brain 5HT activity, as concluded from pharmacological and behavioral studies. Different forms of memory were tested in adult males from 5HT-sublines of WZ-5HT rat as follows: spatial memory (assessed in Morris water maze), short-term memory (assessed as novel object recognition) and avoidance conditioning (assessed as step through passive avoidance). In Morris water maze, high-5HT rats learned platform position faster than low-5HT rats (measured as area under learning curve, P=0.02), but there were no differences in memory score (measured as average distance from previous platform position). Low-5HT rats had tendency to higher novel exploration in novel object recognition task (P=0.05). In the passive avoidance task, 5HT-high rats had higher step through latency (P=0.01) in comparison to low-5HT rats. Testing of multiple types of memory revealed significant differences between animals from 5HT-sublines, pointing to enhanced cognitive performance in high-5HT animals and confirming the importance of serotonin homeostasis in memory formation. Furthermore, this animal model could represent a valuable tool for further investigation of molecular mechanisms underlying cognitive abilities.

serotonin; memory; Wistar-Zagreb 5HT rat

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