Repeated Neonatal Phencyclidine Treatment Impairs Performance of a Spatial Task in Juvenile Rats^a

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Cognitive Neuroscience

Background:

• N-methyl-d-aspartate (NMDA) receptors play a critical role in synaptic plasticity and learning.
• Early-life exposure to certain neurotoxins can lead to long-term cognitive impairments.
• Phencyclidine (PCP) is a non-competitive NMDA receptor antagonist.

Purpose of the Study:

• To investigate the long-term effects of repeated postnatal N-methyl-d-aspartate (NMDA) channel blockade on cognitive function in juvenile rats.
• To determine if early-life NMDA receptor antagonism by phencyclidine (PCP) results in cognitive deficits.
• To assess spatial learning and memory retention following chronic postnatal PCP administration.

Main Methods:

• Juvenile rats were administered phencyclidine (PCP) or saline intraperitoneally daily from postnatal Day 5 to Day 15.
• On postnatal Day 28, rats were tested in the Morris water maze task to assess spatial learning and memory.
• Performance was evaluated based on escape latency and path efficiency over two days of testing.

Main Results:

• PCP-treated rats showed similar performance to saline-treated controls on the first day of Morris water maze testing.
• On the second day of testing, PCP-treated rats performed significantly worse than saline-treated controls.
• This indicates a deficit in spatial information retention in rats exposed to chronic postnatal NMDA channel blockade.

Conclusions:

• Chronic postnatal blockade of the N-methyl-d-aspartate (NMDA) channel by phencyclidine (PCP) impairs spatial memory retention in juvenile rats.
• These findings highlight the critical role of NMDA receptor function during early development for establishing long-term cognitive abilities.
• Early-life NMDA receptor antagonism may lead to persistent cognitive deficits relevant to understanding developmental neurological disorders.