Task-Specific Effects of mGlu2/3 Receptor Agonist LY379268 on MK-801-Induced Behavioral and Neural Dysfunctions in...

Area of Science:

• Neuroscience
• Pharmacology
• Psychiatry

Background:

• NMDA receptor hypofunction is linked to schizophrenia symptoms like hyperlocomotion and cognitive deficits.
• Targeting metabotropic glutamate 2/3 (mGlu2/3) receptors is a potential therapeutic strategy for glutamatergic dysfunction.

Purpose of the Study:

• To investigate if the mGlu2/3 agonist LY379268 can counteract behavioral and neural disruptions induced by the NMDA antagonist MK-801.
• To assess the effects of LY379268 on MK-801-induced impairments in both aversive and non-aversive behavioral tasks and medial prefrontal cortex electrophysiology.

Main Methods:

• Rats were administered MK-801 (0.1 mg/kg) alone or in combination with LY379268 (1 and 2 mg/kg).
• Behavioral testing included an active place avoidance task (aversive learning) and an open field test (non-aversive).
• Local field potentials were recorded from the medial prefrontal cortex during behavioral tasks and under anesthesia.

Main Results:

• LY379268 did not consistently alleviate MK-801-induced impairments; higher doses (2 mg/kg) paradoxically worsened hyperlocomotion and navigation in the aversive task.
• The lower dose (1 mg/kg) of LY379268 showed a modest reduction in MK-801-induced hyperactivity in the non-aversive open field test.
• Electrophysiology revealed MK-801 disrupted theta-high gamma phase-amplitude coupling and increased low gamma power, effects not reversed by LY379268.

Conclusions:

• The effects of LY379268 are task- and dose-dependent, failing to mitigate or sometimes exacerbating deficits in challenging aversive tasks.
• These findings suggest limited therapeutic potential for mGlu2/3 modulation with LY379268 in conditions mimicking glutamatergic dysfunction.
• Further research is needed to refine strategies for mGlu2/3 modulation in neuropsychiatric disorders.