Autoradiographic localization and characterization of atrial natriuretic peptide binding sites in the rat central nervous system and adrenal gland
Atrial natriuretic peptides (ANP) have recently been identified in both heart and CNS. These peptides possess potent natriuretic, diuretic, and vasorelaxant activities, and are all apparently derived from a single prohormone. Specific ANP binding sites have been characterized in the adrenal zona glomerulosa and kidney cortex, and one study reported ANP binding sites in the CNS. However, a detailed examination of the localization of ANP binding sites throughout the brain has not been reported. In this study, quantitative autoradiography was employed to examine the distribution of ANP receptors in the rat CNS. The binding of (3-/sup 125/I-iodotyrosyl28) rat ANP-28 to binding sites in the rat CNS was saturable, specific for ANP-related peptides, and displayed high affinity (Kd = 600 pM). When the relative concentrations of ANP binding sites were determined throughout the rat brain, the highest levels of ANP binding were localized to the circumventricular organs, including the area postrema and subfornical organ, and the olfactory apparatus. Moderate levels of ANP binding sites were present throughout the midbrain and brain stem, while low levels were found in the forebrain, diencephalon, basal ganglia, cortex, and cerebellum. The presence of ANP binding sites in the subfornical organ and the area postrema, regions considered to be outside the blood-brain barrier, suggests that peripheral ANP levels may regulate some aspects of CNS control of salt and water balance. The possible functions of ANP binding sites in other regions of the rat brain are not known, but, like many other peptides, ANP may act as a neurotransmitter or neuromodulator at these loci.
- Research Organization:
- Univ. of Pennsylvania, Philadelphia
- OSTI ID:
- 5127489
- Journal Information:
- J. Neurosci.; (United States), Journal Name: J. Neurosci.; (United States) Vol. 7; ISSN JNRSD
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ADRENAL GLANDS
ANIMALS
AUTORADIOGRAPHY
BODY
CENTRAL NERVOUS SYSTEM
DISTRIBUTION
ENDOCRINE GLANDS
GLANDS
ISOTOPE APPLICATIONS
MAMMALS
MEMBRANE PROTEINS
NERVOUS SYSTEM
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
PROTEINS
RADIORECEPTOR ASSAY
RATS
RECEPTORS
RODENTS
TISSUE DISTRIBUTION
TRACER TECHNIQUES
VERTEBRATES