title: ACTH-immunoreactive boutons form synaptic contacts in the hypothalamic arcuate nucleus of rat: evidence for local opiocortin connections.
abstract: ACTH-like immunoreactive structures were localized in rat hypothalamic arcuate nucleus using the unlabeled antibody, peroxidase-antiperoxidase method. At the ultrastructural level, immunoreactive presynaptic nerve terminals were observed forming symmetrical synaptic contacts with unlabeled dendrites and with ACTH-like immunoreactive perikarya. The results obtained are consistent with the hypothesis that ACTH in the brain acts as a synaptic regulator or transmitter, contributing not only to long projection pathways but also to a local circuit in the arcuate nucleus where ACTH cell bodies are localized.
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000033:anatomy & histology*; D003712:Dendrites / Q000648:ultrastructure; D004723:Endorphins / Q000378:metabolism*; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000378:metabolism*; D008854:Microscopy, Electron; D009434:Neural Pathways / Q000033:anatomy & histology; D009474:Neurons / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013569:Synapses / Q000648:ultrastructure*; D013572:Synaptic Vesicles / Q000648:ultrastructure; D001615:beta-Endorphin; D008083:beta-Lipotropin / Q000378:metabolism*
chemical_list: D004723:Endorphins; D001615:beta-Endorphin; D000324:Adrenocorticotropic Hormone; D009074:Melanocyte-Stimulating Hormones; D008083:beta-Lipotropin