ABSTRACT
The amino acid L-glutamate is a major excitatory neurotransmitter in central nervous system of vertebrates. NMDA( n-methyl-d-aspartate) is one of the L-glutamate receptor subtypes. During a critical period of early postnatal development, the visual cortex is susceptible to experience-dependent modification of neuronal response. Recently, the activation of NMDA receptors has been supposed as an prerequisite for the induction of such modification We therefore investigated developmental changes of NMDA receptors in rat visual cortex and questioned whether they could be related to the visual development. We assessed the density of [3H] NMDA receptor in visual cortex of normally reared rats (Group I) and visually deprivated rats (Group II) using quantitative autoradiography. The density of [3H] NMDA receptor was increased rapidly by postnatal 1 week and decreased after postnatal 5 weeks, and was significantly lower in Group II than Group I during early postnatal period. These results suggest that NMDA receptors may have a role in neuronal development in visual cortex.
Subject(s)
Animals , Rats , Autoradiography , Central Nervous System , Critical Period, Psychological , Glutamic Acid , N-Methylaspartate , Neurons , Neurotransmitter Agents , Receptors, N-Methyl-D-Aspartate , Vertebrates , Visual CortexABSTRACT
The amino acid L-glutamate is a major excitatory neurotransmitter in the central nervous system of vertebrates(1). NMDA (N-methyl-d-aspartate) is one of the L-glutamate receptor subtypes(2). During a critical period of early postnatal development, the visual cortex is susceptible to experience-dependent modification of neuronal responses. Recently, the activation of NMDA receptors has been supposed as a prerequisite for the induction of such modification(3). We therefore investigated developmental changes of NMDA receptors in the rat visual cortex and questioned whether they could be related to the visual development. We assessed the density of [(3)H]-NMDA receptor in the visual cortex of normally reared rate (Group I) and visually deprived rats (Group II) using quantitative autoradiography(4). The density of [(3)H]-NMDA receptor was significantly lower in Group II than in group I during the early postnatal period, and increased rapidly by postnatal 1 week and, decreased after postnatal 5 weeks. These results suggested that NMDA receptors may play a role in neuronal development in the visual cortex during the early postnatal period.