Agonist and antagonist binding to rat brain muscarinic receptors: influence of aging

Journal Article · Sun Mar 01 04:00:00 EST 1987 · Neurobiol. Aging.; (United States)

DOI:https://doi.org/10.1016/0197-4580(87)90020-0· OSTI ID:6332447

Gurwitz, D; Egozi, Y; Henis, Y I; Kloog, Y; Sokolovsky, M

The objective of the present study was to determine the binding properties of muscarinic receptors in six brain regions in mature and old rats of both sexes by employing direct binding of (/sup 3/H)-antagonist as well as of the labeled natural neurotransmitter, (/sup 3/H)-acetylcholine (( /sup 3/H)-AcCh). In addition, age-related factors were evaluated in the modulation processes involved in agonist binding. The results indicate that as the rat ages the density of the muscarinic receptors is altered differently in the various brain regions: it is decreased in the cerebral cortex, hippocampus, striatum and olfactory bulb of both male and female rats, but is increased (58%) in the brain stem of senescent males while no significant change is observed for females. The use of the highly sensitive technique measuring direct binding of (/sup 3/H)-AcCh facilitated the separate detection of age-related changes in the two classes (high- and low-affinity) of muscarinic agonist binding sites. In old female rats the density of high-affinity (/sup 3/H)-AcCh binding sites was preserved in all tissues studied, indicating that the decreases in muscarinic receptor density observed with (/sup 3/H)-antagonist represent a loss of low-affinity agonist binding sites. In contrast, (/sup 3/H)-AcCh binding is decreased in the hypothalamus and increased in the brain stem of old male rats. These data imply sexual dimorphism of the aging process in central cholinergic mechanisms.

• Research Organization: Tel Aviv Univ., Israel
• OSTI ID: 6332447
• Journal Information: Neurobiol. Aging.; (United States), Journal Name: Neurobiol. Aging.; (United States) Vol. 2; ISSN NEAGD
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACETYLCHOLINE
AFFINITY
AGE DEPENDENCE
AMINES
AMMONIUM COMPOUNDS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
AZINES
BIOCHEMICAL REACTION KINETICS
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
DISTRIBUTION
DRUGS
ESTERS
HETEROCYCLIC COMPOUNDS
KINETICS
LABELLED COMPOUNDS
MAMMALS
MEMBRANE PROTEINS
NERVOUS SYSTEM
NEUROREGULATORS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PARASYMPATHOLYTICS
PARASYMPATHOMIMETICS
PIPERIDINES
PROTEINS
PYRIDINES
QUATERNARY COMPOUNDS
RATS
REACTION KINETICS
RECEPTORS
RODENTS
SEX DEPENDENCE
TISSUE DISTRIBUTION
TRITIUM COMPOUNDS
VERTEBRATES