Changes in the brain monoaminergic neurotransmitters and plasma cortisol levels after acute and prolonged benzo (a) pyrene exposure in Acanthopagrus latus

In this study, effects of Benzo (a) pyrene (BaP) exposure on the levels of neurotransmitters in the different regions of brain and plasma levels of cortisol in the Yellowfin Seabream (Acanthopagrus latus) were examined. In the first protocol for assessing the acute stress responses, BaP was injected to a group of fish (50mg/kg BaP in 2μl/g per body weight). The control group for this procedure was injected with oil (2μl/g) per body weight. A group of fish was not injected to assess the basic levels of respective variables. Blood and brain samples from different groups collected 3 hours after injection. To study the long-term a group of fish was implanted with 50mg/kg BaP in 10μl/g coconut oil in respect to the body weight. As the previous protocol a control group was implanted with the same amount of oil without the BaP. Samples were collected from both implanted groups (treatment and control) after 72 hours. In the collected samples, plasma levels of cortisol and contain neurotransmitter in deferens region were assayed. Plasma levels of cortisol in Yellowfin Seabream increased and contain neurotransmitter altered during both short term and long term exposure to the BaP. According to the results, BaP exposure may affect the synthesis, storage, uptake/release and degradation of the neurotransmitters in different regions of the brain, specially the pituitary gland. Serotonin showed more distinct responses under the BaP exposure stress than the other monoamines.