Double immunostaining reveals distinctions among opioid peptidergic neurons in the medial basal hypothalamus.
We adapted an uncommon peroxidase substrate, ortho-dianisidine, to double immunostaining methodology in order to analyze the degree of neuronal coexistence of pro-opiomelanocortin-derived peptides and to compare the distribution of neurons containing beta-endorphin immunoreactivity (ir) with those containing enkephalin-ir and dynorphin-ir in the medial basal hypothalamus. Double immunostaining demonstrated co-localization of beta-endorphin-ir, adrenocorticotropic hormone-ir, and gamma 3-melanocyte stimulating hormone-ir in medial basal hypothalamus (MBH) neurons. However, while all perikarya containing beta-endorphin-ir invariably contained adrenocorticotropic hormone-ir, not all of these cell bodies contained gamma 3-melanocyte stimulating hormone-ir. In contrast, separate neuronal cell bodies containing beta-endorphin-ir, enkephalin-ir, and dynorphin-ir were distributed throughout the rostral-caudal extent of the MBH. Fibers containing enkephalin-ir closely surrounded cell bodies containing beta-endorphin-ir, suggesting axosomatic contacts between these two opioid peptidergic neuronal populations.
D000324:Adrenocorticotropic Hormone / Q000276:immunology; D000818:Animals; D003078:Colchicine / Q000494:pharmacology; D004399:Dynorphins; D004723:Endorphins / Q000276:immunology / Q000502:physiology*; D007033:Hypothalamus, Middle / Q000166:cytology*; D007124:Immunoenzyme Techniques; D009074:Melanocyte-Stimulating Hormones / Q000276:immunology; D009474:Neurons / Q000032:analysis* / Q000276:immunology; D051381:Rats; D011919:Rats, Inbred Strains; D013194:Staining and Labeling
D004723:Endorphins; D004399:Dynorphins; D000324:Adrenocorticotropic Hormone; D009074:Melanocyte-Stimulating Hormones; D003078:Colchicine