Anxiety-related behavior in rats with constitutionally altered serotonergic activity
Serotonin (5HT, 5-hydroxytryptamine) is involved in regulation of both central and peripheral physiological functions, and disturbances in serotonergic neurotransmission are common in neuropsychiatric disorders. Using selective breeding, we have developed Wistar-Zagreb 5HT rats that include two sublines: one with high (high-5HT) and other with low (low-5HT) levels of peripheral (platelet) serotonin and activity of 5HT transporter, representing a rodent model with constitutionally altered serotonin homeostasis. We hypothesized that in these animals, beside peripheral, brain serotonergic activity is also altered which should have effect on their behavioral response. In the present study, we have tested the anxiety-related behavior of 5HT sublines (3 months old males, n=20–21 per subline) in elevated plus maze and open fi eld paradigms. Animals from high-5HT subline had lower score in time spent in open arms and number of entries to the open arms of elevated plus maze in comparison to low-5HT subline (P<0.05). Also, the score of head dip time in open arms was lower in high-5HT subline (P<0.005). In open fi eld test, high-5HT subline had lower score in total rearing time (P<0.005). Altogether, these results confi rm results of previous behavioral tests (hole-board and zero maze) showing differences in anxiety-related behavior in Wistar-Zagreb 5HT rats and indicating higher level of anxietyrelated behavior in high-5HT subline.