Enhanced responses to NMDA receptor activation in the developing cat caudate nucleus

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Neurophysiology

Background:

• The caudate nucleus plays a critical role in motor control and habit formation.
• Understanding the development of neuronal excitability in the caudate nucleus is essential for comprehending motor skill acquisition.

Purpose of the Study:

• To investigate the role of N-methyl-D-aspartate (NMDA) receptor activation in the developing cat caudate nucleus.
• To determine how NMDA receptor-mediated responses change during early postnatal development.

Main Methods:

• Utilized an in vitro slice preparation of the developing cat caudate nucleus.
• Manipulated extracellular magnesium (Mg2+) levels and applied bicuculline to facilitate NMDA receptor activation.
• Recorded excitatory postsynaptic potentials (EPSPs) and action potentials induced by local extracellular stimulation.
• Administered DL-2-amino-5-phosphonovaleric acid (APV), a specific NMDA receptor antagonist, to assess the contribution of NMDA receptors.

Main Results:

• Removal of Mg2+ in the presence of bicuculline increased the amplitude and duration of EPSPs across all tested ages.
• In younger neurons ( < 35 days), Mg2+ removal induced bursts of action potentials.
• These NMDA receptor-mediated effects were reversible and attenuated by APV.

Conclusions:

• NMDA receptor-mediated responses can be elicited in developing caudate neurons via local extracellular stimulation.
• These NMDA receptor responses are potentiated during early postnatal periods, coinciding with motor control establishment.
• Findings highlight the developmental significance of NMDA receptor function in the caudate nucleus for motor development.