DNA integrity-protecting and survival-promoting activity of serotonergic system in sturgeon juveniles and sazans.

The study concerns evaluation of engagement of serotonergic system in the mechanisms of antimutagenic protection and survival under adverse conditions. It is shown that under long-term exposure to oil and industrial pollution, simultaneous sharp increase of mutations level in the erythrocytes and downregulation of serotonin-modulating anticonsolidation protein (SMAP; Mekhtiev 2000) in the livers of the sturgeon juveniles (Acipenser gueldenstaedtii persicus) is observed. Mutation level was evaluated by the micronucleus analysis and SMAP level-by the indirect ELISA-test utilizing anti-SMAP immunoglobulins. Intramuscular administration of SMAP leads to significant decrease of micronucleus amount in the erythrocytes of the sturgeon juveniles exposed to sediments polluted with PAH and heavy metals. Pre-conditioning of sazans by low dose of insecticide actara (100 mg/l) leads to upregulation of SMAP and to survival of all the animals in the experimental group, kept under high concentration of actara (400 mg/l), while all animals in the control group succumbed under these conditions. I.m. administration of SMAP prior to putting the sazans into the water containing high levels of actara (400 mg/l), in contrast to controls, leads to their total survival. Participation of serotonergic system in the mechanisms of antimutagenic protection and survival promotion under damaging conditions is concluded.