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ANGIOTENSIN IMMUNOREACTIVITY IN VASOPRESSIN CELLS IN RAT HYPOTHALAMUS AND ITS RELATIVE DEFICIENCY IN HOMOZYGOUS BRATTLEBORO RATS *
Author(s) -
Hoffman D. L.,
Krupp L.,
Schrag D.,
Nilaver G.,
Valiquette G.,
Kilcoyne M. M.,
Zimmerman E. A.
Publication year - 1982
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.1982.tb37419.x
Subject(s) - columbia university , neurology , medicine , annals , family medicine , classics , psychiatry , history , media studies , sociology
It has been twenty years since a role for angiotensin I1 (AII) in the regulation of blood pressure by the central nervous system was suggested by crosscirculation experiments in dogs.’ Administration of small doses of A11 into the brain revealed additional central actions including thirst, vasopressin (VP) and adrenocorticotropin (ACTH) secretion, sodium appetite, and suppression of renal renin.? Although an endogenous brain renin-angiotensin system was proposed ten years its existence is still debated.‘, 5 , One issue now apparently resolved concerned the presence of a renin enzyme in brain distinct from cathepsin D.7 Another has been the inability of most laboratories to extract significant quantities of endogenous A11 from brain.? Therefore, it is still not known whether brain renin is actually involved in the production of angiotensin 11, and whether this might occur within specific neuronal systems. Immunoreactive renin has been demonstrated in neurons in the supraoptic (SON), paraventricular (PVN) and suprachiasmatic (SCN) nuclei of hypothalamus, as well as other brain regions of the mouse.8 In addition, the possibility that a single cell can contain the entire renin-angiotensin system was recently demonstrated in a neuroblastoma-glioma X cell line in tissue c u l t ~ r e . ~ In recent years AII-like immunoreactivity has been reported in nerve fibers in a number of regions of the brain and spinal cord by immunocytochemical The neuronal perikarya most consistently labeled within the cytoplasm were found in the magnocellular nuclei of the hypothalamus: SON and PVN.l3-lS We previously reported that the “MI-like” reactivity in the SON and PVN was localized in vasopressin-containing neurons and behaved like vasopressin: it increased in fibers to the zona externa (ZE) of the median eminence (ME) in response to adrenalectomy, and was deficient in homozygous Brattleboro rats (DI rats), which also lack v a s o p r e s ~ i n . ~ ~ ~ l6 We also suggested that the antiserum had some preference for 5-valine A11 compared to 5isoleucine AII.16 In this communication we report the results of further experiments with DI rats, and additional absorption studies on normal rat hypothala-