REGULATION OF SYNAPSE DENSITY BY 5-HT2A RECEPTOR AGONIST AND ANTAGONIST IN THE SPINAL-CORD OF CHICKEN-EMBRYO

Identification of mechanisms that regulate the number of synapses in t he brain has been a key issue for understanding the mechanism of plast icity. Here, we report that the density of synapses can be changed usi ng an antagonist and/or an agonist of serotonin (5-HT) type 2A recepto rs in the chicken spinal cord. Because of the widespread distribution pattern of 5-HT fibers and 5-HT2A receptors in the central nervous sys tem, 5-HT is thought to play a role in the formation and maintenance o f synapses that are involved in normal brain function and mechanism of plasticity.