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Localization of hypothalamic neurons that contain orexin or melanin concentrating hormone peptides and regulate diaphragm activity in cats
Author(s) -
Badami Varun M,
Rice Cory D,
Lois James H,
Madrecha Jayesh,
Yates Bill J
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.1064.11
Subject(s) - orexin , lateral hypothalamus , hypothalamus , orexin a , melanin concentrating hormone , medicine , endocrinology , biology , cats , neuropeptide , brainstem , energy homeostasis , hormone , neuroscience , receptor , obesity
A variety of studies have shown that the lateral hypothalamus (LH) participates in controlling breathing. The LH also contains many neurons that each produce one of two peptides that modulate homeostasis and emotional states: orexin and melanin concentrating hormone (MCH). The present study tested the hypothesis that hypothalamic neurons that influence diaphragm activity contain either orexin or MCH. For this purpose, rabies virus was injected into the diaphragm of cats to transneuronally infect hypothalamic neurons with multisynaptic connections to phrenic motoneurons; immunohistochemistry was performed to dual‐localize rabies and either orexin or MCH. In animals with early rabies infection of LH, a large fraction of the infected hypothalamic neurons contained orexin: 19–75%, median of 30%. However, in animals with advanced infections where rabies had passed through additional synapses, only 8–10% of the infected cells were orexinergic. In contrast, just 6–33% (median 11%) of the early‐infected LH neurons were immunopositive for both MCH and rabies. These data show that an appreciable number of LH neurons with the most direct influences on diaphragm activity contain either orexin or MCH, although most of these cells are orexinergic. These findings therefore suggest that orexins play a central role in conveying signals from the diencephalon to brainstem and spinal regions that regulate breathing.