Selective effect of chronic lead ingestion on tyrosine hydroxylase activity in brain regions of rats.

The Effect of Lead Exposure on Autism Development

“…The accumulation of lead in the body has various consequences on the functioning of the central nervous system (CNS) [7,9,11,[28][29][30][31][32][33][34][35]. Previous studies have highlighted alterations in several neurological mechanisms subsequent to lead exposure [7,9,11,[28][29][30][31][32][33][34][35]. Prior research has emphasized the role of proper molecular structure in the adequate functioning of neurological mechanisms [36].…”

“…Lead, in particular has been associated with the alteration of the release and reuptake of several neurotransmitters [30]. Overall, changes among the cholinergic, dopaminergic, serotonergic, and glutamatergic systems are common among lead-exposed individuals [7,9,11,[28][29][30][31][32][33][34][35]. Alterations within these neurological systems have been associated with several autistic symptoms, including deficits in behavior, decrements in learning and cognitive abilities, reading and writing impairments, memory loss, changes in the stress response, as well as increased anxiety [13][14][15].…”

“…Particularly, activation of protein kinase C by lead inhibits Na + /K + -ATPase, an enzyme accountable for more than two-thirds of the brain's energy disbursement/expenditure [38]. One study highlighted lower Na + /K + -ATPase activity rin ats exposed to 0.05-0.2% of lead acetate compared to unexposed rats [35]. Another study found a 54% decrease in ATP levels in lead-exposed animals [31].…”

“…This further suggests lead's role in altering dopaminergic function via PKC. Modifications within the dopaminergic system due to the presence of lead may result in neurological deficits concerning language and reading capability, memory, and social ability [35].…”

“…Other dopaminergic parameters have also been shown to be impacted by lead. Prior studies have shown that the activity of tyrosine hydroxylase, the limiting enzyme in dopamine synthesis, was significantly impacted by excessive lead exposure [35]. Studies have correlated imbalances in dopamine to several neurological deficits as well as disorders, such as Alzheimer's disease, further suggesting a role for lead in initiating autistic symptoms.…”