The Descending Projection of Serotoninergic,Fibers in the Raphe Nucleus of Brainstem and Its,Adjacent Areas in the Rat——A Double Labeled Study of HRP and Immunohistochemistry

Rats(Sprague Dawley,200-300g)wereoperated under anesthesia with nembuta1.Afterthe laminectomy,20-25%aqueous solution ofHRP(Sigma 6)was injected unilatera11y intothe spinal cord at cervical or lumbar leve1.Theanimals were allowed to survive for 36-48hours and transcardically perfused with 0.9%NaCl,3.5%paraforma1dehyde,and 10%sucr-ose in 0.1mol/L PB.The brain was removed andimmersed in 10%sucrose at 4℃.