Systemic cholinergic agents induce seizures and brain damage in lithium-treated rats

Area of Science:

• Neuroscience
• Pharmacology
• Toxicology

Background:

• Lithium is widely used in psychiatric chemotherapy.
• Pilocarpine and physostigmine are cholinergic agonists.
• Phosphoinositide metabolism is crucial for neuronal function.

Purpose of the Study:

• To investigate the neurotoxic effects of combining cholinergic agonists with lithium.
• To examine the role of D-myo-inositol-1-phosphate in lithium-induced neurotoxicity.
• To determine if atropine can prevent this toxic syndrome.

Main Methods:

• Rats were treated with lithium chloride followed by pilocarpine or physostigmine.
• Brain tissue and blood lithium concentrations were analyzed.
• Levels of D-myo-inositol-1-phosphate were measured.
• The effect of atropine administration was assessed.

Main Results:

• Combined administration of lithium with pilocarpine or physostigmine induced sustained limbic seizures and widespread brain damage.
• Elevated brain concentrations of D-myo-inositol-1-phosphate were observed.
• Atropine effectively prevented the development of the neurotoxic syndrome.
• The effective doses of physostigmine and lithium levels were comparable to therapeutic psychiatric doses.

Conclusions:

• Cholinergic overstimulation in the context of lithium treatment can lead to severe neurotoxicity.
• D-myo-inositol-1-phosphate accumulation may be a marker of this toxicity.
• Atropine exhibits protective effects against this lithium-cholinergic neurotoxic syndrome.
• These findings highlight potential risks associated with combined drug therapies in psychiatry.