Projections from the anterior basomedial and anterior cortical amygdaloid nuclei to melanin-concentrating hormone-containing neurons in the lateral hypothalamus of the rat.
Melanin-concentrating hormone (MCH) is involved in the regulation of feeding behavior as well as in goal oriented behaviors, and MCH-containing neurons are distributed mainly in the lateral hypothalamic area (LHA). The anterior basomedial nucleus (BMA) and anterior cortical nucleus (CoA) of the amygdala form part of a circuit involved in processing olfactory, gustatory and visceral information, and the BMA-LHA and CoA-LHA pathways are suggested to be implicated in the control of feeding behavior. However, it is still unknown whether or not MCH-containing LHA neurons are under the direct influence of the BMA and CoA. Here the organization of projections from the BMA and CoA to MCH-containing LHA neurons was examined. Using a combined anterograde tracing with biotinylated dextranamine and immunohistochemistry for MCH, we first demonstrated that the distribution pattern of BMA fibers was almost similar to that of CoA fibers in the LHA, and a prominent overlapping distribution of these fibers and MCH-immunoreactive neurons existed in the ventral peripeduncular region of the LHA. We further revealed that asymmetrical synapses were made between these fibers and neurons. Using a combination of retrograde tract-tracing with cholera toxin B subunit and in situ hybridization for vesicular glutamate transporter (VGLUT) 2 mRNA, we finally showed that most of the LHA-projecting BMA and CoA neurons expressed VGLUT2 mRNA. These data suggest that the BMA and CoA of the amygdala may exert excitatory influence upon the MCH-containing LHA neurons for the regulation of feeding behavior.
Department of Anatomy and Morphological Neuroscience, Shimane University School of Medicine, 89-1 Enya-cho, Izumo 693-8501, Japan.
Jian-Guo
JG
Niu
Shigefumi
S
Yokota
Toshiko
T
Tsumori
Tatsuro
T
Oka
Yukihiko
Y
Yasui
D000679:Amygdala / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D000818:Animals; D007026:Hypothalamic Area, Lateral / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D007028:Hypothalamic Hormones / Q000032:analysis / Q000502:physiology*; D008297:Male; D008543:Melanins / Q000032:analysis / Q000502:physiology*; D009415:Nerve Net / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D009434:Neural Pathways / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D009474:Neurons / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D010907:Pituitary Hormones / Q000032:analysis / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
D007028:Hypothalamic Hormones; D008543:Melanins; D010907:Pituitary Hormones; C019463:melanin-concentrating hormone