Quantitative autoradiography of 125I-(Sar1, Ile8)-angiotensin II binding in the brain of spontaneously hypertensive rats

Journal Article · Tue Dec 31 23:00:00 EST 1985 · Brain Res. Bull.; (United States)

DOI:https://doi.org/10.1016/0361-9230(86)90014-6· OSTI ID:5742818

Hwang, B H; Harding, J W; Liu, D K; Hibbard, L S; Wieczorek, C M; Wu, J Y

The brain contains its own angiotensin II (AII) system. To better understand the role of central AII in cardiovascular regulation, we used 125I-(Sar1, Ile8)-AII (125I-SI-AII), radioactive AII antagonist, to autoradiographically localize putative AII receptor binding in many parts of the central nervous system of the spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats. With 125I-SI-AII binding on brain membrane preparations. Scatchard analysis indicated that Kd values were from 0.10 +/- 0.04 nM to 0.13 +/- 0.05 nM, whereas Bmax values (femtomol/mg protein) were found to be from 6.95 +/- 1.60 to 15.52 +/- 4.99 among brain regions studied. Various SI-AII receptor binding activities among brain regions revealed in this study were therefore most likely due to differences in AII receptor density with high affinity binding of 125I-AII. Using 125I-SI-AII, specific binding for SI-AII was found in the nucleus tractus solitarius (NTS), paraventricular hypothalamic nucleus (PVN), subfornical organ (SFO), suprachiasmatic nucleus (SCN), area postrema, the dorsal motor nucleus of the vagus (DMX), and the nucleus of spinal tract of the trigeminal system (NSV). With quantitative receptor autoradiography in conjunction with radioactive standards, we have observed that the NTS possesses the highest SI-AII binding, followed by the PVN, SFO, NTS, DMX, and NSV. No significant differences were observed between the SHR and WKY rats in the SI-AII binding within the SFO, PVN and NTS. However, SHR at early hypertensive (7 weeks) and established hypertensive (16 weeks) stages contained significantly higher SI-AII bindings in the NSV, as compared to age-matched WKY rats.

• Research Organization: Pennsylvania State Univ., Hershey
• OSTI ID: 5742818
• Journal Information: Brain Res. Bull.; (United States), Journal Name: Brain Res. Bull.; (United States) Vol. 1; ISSN BRBUD
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANGIOTENSIN
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BODY
BRAIN
CARDIOVASCULAR AGENTS
CARDIOVASCULAR DISEASES
CENTRAL NERVOUS SYSTEM
CHEMICAL BONDS
DAYS LIVING RADIOISOTOPES
DISEASES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
GLOBULINS
HYPERTENSION
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
MAMMALS
MEMBRANE PROTEINS
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RADIOISOTOPES
RATS
RECEPTORS
RODENTS
SYMPTOMS
VASCULAR DISEASES
VASOCONSTRICTORS
VERTEBRATES