Major pro-vasopressin-expressing and pro-vasopressin-deficient subpopulations of corticotropin-releasing hormone neurons in normal rats. Differential distributions within the paraventricular nucleus.
Two approximately equal subpopulations of corticotropin-releasing hormone (CRH)-containing parvocellular axons can be identified in the external zone of the median eminence in normal (unadrenalectomized) rats: one that contains pro-vasopressin (AVP)-derived peptides (i.e. AVP, AVP-associated neurophysin and the carboxy terminal glycopeptide) copackaged with CRH in secretory vesicles, and another that contains no detectable pro-AVP-derived peptides. In this study, antibodies to pro-AVP-derived peptides were used to demonstrate for the first time that similar subpopulations of CRH-containing parvocellular perikarya exist in the paraventricular nucleus of the hypothalamus in normal rats treated with colchicine. Electron-microscopic immunocytochemistry was performed on serial ultrathin sections to identify neurosecretory cell perikarya containing CRH that also expressed pro-AVP peptides or pro-oxytocin-derived neurophysin. Of the CRH-positive neurons that were detected, more than half stained positively for two pro-AVP peptides: AVP-associated neurophysin and the carboxy-terminal glycopeptide. Many of these cells also stained for AVP, but staining was variable, making quantitation of AVP-positive cells difficult. The remaining CRH-positive neurons contained no detectable pro-AVP peptides, and less than 0.5% of these CRH perikarya contained oxytocin-associated neurophysin. In the neurons that stained positively for both CRH and the pro-AVP peptides, CRH and the pro-AVP peptides were localized in the same secretory vesicles. The pro-AVP expressing and pro-AVP-deficient CRH neurons were distributed differently within the paraventricular nucleus.(ABSTRACT TRUNCATED AT 250 WORDS)
Whitnall
M H
MH
Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, Bethesda, Md.
Gainer
H
H
D000818:Animals; D001127:Arginine Vasopressin; D003346:Corticotropin-Releasing Hormone / Q000032:analysis*; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D009474:Neurons / Q000032:analysis* / Q000145:classification; D009481:Neurophysins / Q000032:analysis; D010121:Oxytocin; D010286:Paraventricular Hypothalamic Nucleus / Q000032:analysis* / Q000648:ultrastructure; D011498:Protein Precursors / Q000032:analysis* / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D014667:Vasopressins / Q000032:analysis* / Q000378:metabolism
D009481:Neurophysins; D011498:Protein Precursors; D014667:Vasopressins; D001127:Arginine Vasopressin; D010121:Oxytocin; D003346:Corticotropin-Releasing Hormone