Ca/sup 2 +/-CaM-ATPase activity after corticosterone binding to synaptosomal plasma membrane

Conference · Sat Mar 01 04:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5388901

Iqbal, Z; Sze, P Y

Studies conducted in the laboratory have demonstrated that corticosterone (CS) binds specifically to synaptosomal plasma membrane (SPM) and modify the cellular events in the synaptosomes. On an exposure of a rat brain synaptosomes to physiological concentrations (<1..mu..M) of CS, the uptake of /sup 45/Ca/sup 2 +/ into synaptosomes was increased by 40-50%. Similarly the binding of /sup 45/Ca/sup 2 +/ to isolated SPM was also enhanced by 50% in the presence of CS. However when intact synaptosomes were pre-incubated with CS, the capacity of membranes to bind /sup 45/Ca/sup 2 +/ was increased by 2-fold. After the incubation of intact synaptosomes with < ..mu..M CS, the activity of trifluoperazine sensitive and CaM dependent Ca/sup 2 +/-ATPase at 1..mu..M Ca/sup 2 +/ was found to be stimulated by 20-30% whereas the activity of Ca/sup 2 +/-ATPase at 1mM Ca/sup 2 +/ remained unaffected. Exposure of synaptosomes to CS was also effective in protecting the reduction of ouabain-sensitive ATPase (Na/sup +/-K/sup +/-ATPase) activity caused by 0.5% ethanol used as a solvent medium for CS. These findings suggest that one of the physiological actions of CS in synaptosomes, after binding to synaptosomal plasma membranes, is an enhancement of Ca/sup 2 +/ transport and an increase of Ca/sup 2 +/-CaM-ATPase activity.

• Research Organization: Chicago Medical School, North Chicago, IL
• OSTI ID: 5388901
• Report Number(s): CONF-8604222-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:3
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID ANHYDRASES
ADRENAL HORMONES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
ATP-ASE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BODY
BRAIN
CALCIUM 45
CALCIUM COMPOUNDS
CALCIUM ISOTOPES
CELL CONSTITUENTS
CELL MEMBRANES
CENTRAL NERVOUS SYSTEM
CORTICOSTEROIDS
CORTICOSTERONE
DAYS LIVING RADIOISOTOPES
ENZYME ACTIVITY
ENZYMES
EVEN-ODD NUCLEI
GLUCOCORTICOIDS
HORMONES
HYDROLASES
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
KETONES
KINETICS
MAMMALS
MEMBRANE TRANSPORT
MEMBRANES
NERVES
NERVOUS SYSTEM
NUCLEI
ORGANIC COMPOUNDS
ORGANS
PHOSPHOHYDROLASES
PREGNANES
RADIOISOTOPES
RATS
REACTION KINETICS
RODENTS
STEROID HORMONES
STEROIDS
TRACER TECHNIQUES
UPTAKE
VERTEBRATES