title: Reciprocal connections between CART-immunoreactive, hypothalamic paraventricular neurons and serotonergic dorsal raphe cells in the rat: Light microscopic study.
abstract: Based on the overlapping physiological roles of cocaine- and amphetamine-regulated transcript (CART) peptides and serotonin, the present study examined the anatomical connection between the hypothalamic paraventricular nucleus (PVN) and the dorsal raphe (DR). The first series of experiments were performed to investigate descending projections from the CART-immunoreactive (CART-ir) PVN to serotonergic DR cells. CART-ir varicosities made contact with serotonergic DR neurons. An anterograde tracing study revealed that varicosities originating from the PVN formed close appositions to serotonergic neuronal profiles along the entire rostro-caudal extent of the DR. A retrograde study demonstrated that CART neurons projecting to the DR were mainly localized in the caudal parvicellular PVN, comprising approximately 3.0%±0.4% (n=8) of total CART cells. A second series of experiments was performed to investigate ascending projections from the DR to CART-ir PVN cells. Serotonin transporter-ir boutons made contact with CART-ir PVN neurons. Anterograde tracing revealed that varicosities originating from the DR formed close appositions to CART-ir PVN cells. Retrograde examination demonstrated that serotonergic neurons projecting to the parvicellular PVN were located along the entire rostro-caudal extent of the DR. The present observation provided an anatomical basis for accumulating evidence in the literature that suggests a functional interaction between the CART and serotonin systems during the regulation of energy balance, emotional behavior, and arousal.
authors.affiliation: Department of Anatomy, School of Medicine, Konkuk University, 143-701 Seoul, South Korea.
authors.forename: Ji S
authors.initials: JS
authors.lastname: Lee
authors.affiliation: Department of Anatomy, School of Medicine, Konkuk University, 143-701 Seoul, South Korea; Research Institute of Medical Science, School of Medicine, Konkuk University, 143-701 Seoul, South Korea. Electronic address: hyunsook.lee@kku.ac.kr.
authors.forename: Hyun S
authors.initials: HS
authors.lastname: Lee
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism; D005260:Female; D005455:Fluorescent Antibody Technique; D008297:Male; D018613:Microscopy, Confocal; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009434:Neural Pathways / Q000033:anatomy & histology / Q000378:metabolism; D056347:Neuroanatomical Tract-Tracing Techniques; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D010286:Paraventricular Hypothalamic Nucleus / Q000033:anatomy & histology* / Q000378:metabolism; D010784:Photomicrography; D017729:Presynaptic Terminals / Q000378:metabolism; D011903:Raphe Nuclei / Q000033:anatomy & histology* / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D059326:Serotonergic Neurons / Q000166:cytology* / Q000378:metabolism; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein
chemical_list: D009419:Nerve Tissue Proteins; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein
keywords: Cocaine- and amphetamine-regulated transcript (CART); Dorsal raphe (DR); Hypothalamic paraventricular nucleus (PVN)