p,p'-DDT-induced alterations in brain serotonin metabolism

Area of Science:

• Neuroscience
• Toxicology
• Pharmacology

Background:

• p,p'-DDT exposure causes myoclonus, a condition responsive to serotonin modulating drugs.
• The precise neurochemical mechanisms underlying p,p'-DDT-induced myoclonus remain unclear.

Purpose of the Study:

• To investigate the impact of p,p'-DDT on serotonin metabolism in various rat brain regions.
• To determine if altered serotonin levels or turnover explain the observed myoclonus and drug responses.

Main Methods:

• Rats were administered p,p'-DDT (600 mg/kg, intragastrically).
• Concentrations of tryptophan, serotonin, and 5-hydroxyindoleacetic acid were measured in plasma and seven brain regions.
• Serotonin turnover, transport, uptake, release, and receptor binding were assessed.

Main Results:

• p,p'-DDT elevated plasma tryptophan and brain tryptophan and 5-hydroxyindoleacetic acid levels across all regions.
• Serotonin levels increased only in the midbrain and cerebellum.
• Serotonin turnover was enhanced in the medulla and midbrain, with no significant effects on transport, uptake, release, or receptor binding.

Conclusions:

• The study does not support a brain serotonin deficiency as the cause of p,p '-DDT-induced myoclonus.
• Observed alterations in serotonin metabolism do not fully explain the myoclonus or its modulation by serotonin agonists/antagonists.