Involvement of serotonergic receptors in endosulfan neurotoxicity

Single dose of 1 and 3 mg/kg endosulfan did not show any significant effect on binding of 3H-serotonin to frontal cortical membranes as well as on foot-shock-induced fighting behaviour in rats, where as repeated exposure of endosulfan (3 mg/kg for 30 days) caused a significant increase in 3H-serotonin binding. Scatchard analysis showed an increase in the affinity of the receptor (KD) in the treated animals while number of receptor sites (Bmax) remained unaltered. Long term endosulfan exposure caused aggressive behaviour (foot-shock-induced fighting behaviour) which was blocked by methysergide, a 5-HT blocker. These results indicate the involvement of serotonergic receptors in endosulfan neurobehavioral toxicity.