Table 2. The mean concentrations of oxytocin and serotonin in horse blood plasma for different degrees of fearfulness in horses

Neurotransmitters Degree of fearfulness
Low (n = 13) Medium (n = 5) High (n = 11)
OXT (pg/mL) 47.33 ± 2.42 46.13 ± 2.53 41.16 ± 1.92
5-HT (ng/mL) 94.54 ± 5.99 103.19 ± 7.39 82.85 ± 6.06