Ultrastructure of Fronto-Accumbens Synapses after Prefrontal Decortication of the Rat / 대한해부학회지

ABSTRACT

Prefrontal cortex is called psycological cortex, since it deals with making up of individual personality, regulation of personal depth of feeling, working memory, planning, maintaining attention, etc. Whereas, nucleus accumbens (septi) is called the center of reward and motivation or the center of pleasure, since it deals with feeding, drinking, sex, exploration, appetitive learning, drug addiction, etc. Present study was aimed at the proving the prefronto-accumbens input ultrastructurally. Sprague Dawley rats anesthetized with sodium pentobarbital and were removed their prefrontal cortex with suction instrument. Two days following the operation, heads of rats were fixed by perfusion of with 1% glutaraldehyde-1% paraformaldehyde solution via left ventricle. Peristaltic pump was used during perfusion. Two hours later, brains were removed and refixed for 24 hours in the refrigerator, and small tissues of the nucleus accumbens were punched out with punching needle. Tissue blocks were fixed in 2% osmic acid for 2 hours and were embedded in araldite mixture. Ultrathin sections stained with uranyl acetate-lead citrate solution were observed with JEOL 100 CX II electron microscope. In the nucleus accumbens, some axodendritic terminals and axospinous terminals were found degenerated, and volume of activated glial cytoplasm was increased. The degenerated terminals were seen isolated from intact structures by activated glial processes and removed by glial cytoplasm. The result confirms that axon terminals coming from prefrontal cortex input to the spiny neurons of nucleus accumbens septi, on their dendrites and/or dendritic spines.