Endogenous GABA concentration in cortical synaptosomes from young and aged rats

Area of Science:

• Neuroscience
• Biochemistry
• Aging Research

Background:

• Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the mammalian central nervous system.
• Synaptosomes are isolated nerve terminals that are crucial for studying neurotransmitter uptake and release.
• Age-related changes in neurotransmitter systems can impact cognitive function and neurological health.

Purpose of the Study:

• To compare GABA concentration in cortical synaptosomes between young and aged rats.
• To evaluate the effect of Millipore filtration on GABA concentration measurements.
• To assess age-related decline in GABAergic function within synaptosomes.

Main Methods:

• Cortical synaptosomes were isolated from young (2-month) and aged (30-month) male Long-Evans rats.
• GABA concentrations were measured in both the overall synaptosomal preparation and in synaptosomes retained by 0.65 μm pore size Millipore filters.
• Statistical analysis was used to compare GABA levels between age groups and filtration methods.

Main Results:

• Overall GABA concentration in synaptosomal preparations decreased from 2.97 mM in young rats to 2.68 mM in aged rats.
• Millipore filtration enriched GABA concentration, yielding levels over three times higher than the overall preparation for both age groups.
• GABA concentration in filtered synaptosomes declined more significantly in aged rats (from 9.33 mM to 8.37 mM) compared to the overall preparation.

Conclusions:

• Aging leads to a significant reduction in cortical synaptosomal GABA concentration.
• Millipore filtration effectively isolates synaptosomes but highlights a greater age-dependent decline in GABA content within these purified nerve terminals.
• These findings suggest impaired GABAergic neurotransmission in the aging brain.