Implication of thyroid hormone receptors in methamphetamine neurocognitive effects

Area of Science:

• Neuroscience
• Endocrinology
• Pharmacology

Background:

• Methamphetamine (MA) is known to cause neurocognitive deficits through various mechanisms.
• Thyroid hormones (THs) play a crucial role in brain development and function, including memory processes.
• The specific impact of MA on thyroid hormone receptors and the potential for THs to counteract MA-induced memory impairment remain underexplored.

Purpose of the Study:

• To investigate alterations in thyroid hormone receptor expression following MA-induced memory impairment.
• To explore the potential neuroprotective effects of exogenous thyroid hormones (T3 and T4) against MA-induced memory deficits.

Main Methods:

• Male Wistar rats were administered escalating doses of MA.
• Following MA treatment, rats received intranasal T3 or intraperitoneal T4.
• Memory function was assessed using the novel object recognition test.
• Hippocampal mRNA levels of thyroid hormone nuclear receptors (TRα1, TRβ1) and seladin-1 were quantified.
• Hippocampal protein levels of the TH cell surface receptor (integrin αvβ3) were measured.

Main Results:

• MA-induced memory impairment correlated with decreased TRα1 mRNA levels in the hippocampus.
• Both T3 and T4 treatments significantly ameliorated MA-induced memory impairment.
• Exogenous THs did not significantly alter the mRNA levels of nuclear thyroid hormone receptors.
• T4 treatment notably increased the protein level of the integrin αvβ3 (αv subunit) in MA-exposed rats.

Conclusions:

• Methamphetamine's neurocognitive effects may involve the disruption of thyroid hormone signaling pathways in the brain.
• Exogenous thyroid hormones demonstrate therapeutic potential in mitigating methamphetamine-induced memory impairment.
• The findings highlight the brain's TH signaling pathway as a promising target for treating MA-induced cognitive deficits.