Evidence for thymopoietin and thymopoietin/. alpha. -bungarotoxin/nicotinic receptors within the brain

Journal Article · Fri Mar 15 00:00:00 EST 1991 · Proceedings of the National Academy of Sciences of the United States of America; (United States)

DOI:https://doi.org/10.1073/pnas.88.6.2603· OSTI ID:5030148

Quik, M ^[1]; Babu, U; Audhya, T; Goldstein, G ^[2]

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1. McGill Univ., Montreal, Quebec (Canada)
2. Immunobiology Research Inst., Annandale, NJ (United States)

Thymopoietin, a polypeptide hormone of the thymus that has pleiotropic actions on the immune, endocrine, and nervous systems, potently interacts with the neuromuscular nicotinic acetylcholine receptor. Thymopoietin binds to the nicotinic {alpha}-bungarotoxin ({alpha}-BGT) receptor in muscle and, like {alpha}BGT, inhibits cholinergic transmission at this site. Evidence is given that radiolabeled thymopoietin similarly binds to a nicotinic {alpha}-BGT-binding site within the brain and does so with the characteristics of a specific receptor ligand. Thus specific binding to neuronal membranes was saturable, of high affinity linear with increased tissue concentration, and readily reversible; half-time was {approximately}5 min for association and 10 min for dissociation. Binding of {sup 125}I-labeled thymopoietin was displaced not only by unlabeled thymopoietin but also by {alpha}-BGT and the nicotinic receptor ligands d-tubocurarine and nicotine; various other receptor ligands (muscarinic, adrenergic, and dopaminergic) did not affect binding of {sup 125}I-labeled thymopoietin. Thymopoietin was shown by ELISA to be present in brain extracts, displacement curves of thymus and brain extracts being parallel to the standard thymopoietin curve, and Western (immuno) blot identified in brain and thymus extracts a thymopoietin-immunoreactive polypeptide of the same molecular mass as purified thymopoietin polypeptide. The authors conclude that thymopoietin and thymopoietin-binding sites are present within the brain and that the receptor for thymopoietin is the previously identified nicotinic {alpha}-BGT-binding site of neuronal tissue.

• OSTI ID: 5030148
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (United States), Vol. 88:6; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
PEPTIDE HORMONES
RADIORECEPTOR ASSAY
RECEPTORS
BIOCHEMICAL REACTION KINETICS
ACETYLCHOLINE
BRAIN
ENZYME IMMUNOASSAY
IODINE 125
LIVER
NICOTINIC ACID
POLYPEPTIDES
THYMUS
TOXINS
AMINES
AMMONIUM COMPOUNDS
ANTIGENS
AUTONOMIC NERVOUS SYSTEM AGENTS
AZINES
BETA DECAY RADIOISOTOPES
BIOASSAY
BODY
CARBOXYLIC ACIDS
CENTRAL NERVOUS SYSTEM
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ESTERS
GLANDS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HORMONES
IMMUNOASSAY
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LYMPHATIC SYSTEM
MATERIALS
MEMBRANE PROTEINS
NERVOUS SYSTEM
NEUROREGULATORS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PARASYMPATHOMIMETICS
PEPTIDES
PROTEINS
PYRIDINES
QUATERNARY COMPOUNDS
RADIOISOTOPES
REACTION KINETICS
TOXIC MATERIALS
TRACER TECHNIQUES
VITAMIN B GROUP
VITAMINS
550201* - Biochemistry- Tracer Techniques