Effects of vanadium on different adenosinetriphosphatases and binding of /sup 3/H-labeled ouabain and calcium-45 to rat brain synaptosomes

Journal Article · Tue Sep 01 04:00:00 EDT 1981 · J. Toxicol. Environ. Health; (United States)

DOI:https://doi.org/10.1080/15287398109530082· OSTI ID:5704899

Mishra, S K; Osborn, R L; Desaiah, D

The effect of vanadium chloride on rat brain synaptosomal adenosinetriphosphatase (ATPase) activities was determined in vitro and in rats treated at 1 mg/kg and 10 mg/kg for 10 d. Additional experiments were conducted to determine the effect of vanadium chloride on binding of (/sup 3/H)ouabain and /sup 45/Ca to rat brain synaptosomes. Na/sup +/ + K/sup +/- and Ca/sup 2 +/-ATPase activities were inhibited significantly in a concentration-dependent manner by V in vitro. Mg/sup 2 +/-ATPase inhibition was neither dose-dependent nor significant except at 10/sup -5/M. Na/sup +/ + K/sup +/-ATPase inhibition by V was more pronounced than that of other ATPases studied. Vanadium inhibited (/sup 3/H)ouabain binding to synaptosomes by 90% at 10/sup -3/ M; the inhibition was concentration-dependent. Binding of /sup 45/Ca was inhibited 50% at 10/sup -4/ M; but concentration-dependent inhibition was not evident. Rats treated with vanadium chloride neither became myotonic nor showed any changes in ATPase activities or binding of (/sup 3/H)ouabain and /sup 45/Ca to brain synaptosomes. Line-weaver-Burke plots of the in vitro inhibition of Na/sup +/ + K/sup +/-ATPase and (/sup 3/H)ouabain binding revealed that (1) Na/sup +/ + K/sup +/-ATPase activation by ATP was inhibited by V with an increase in K/sub m/ and a decrease in V/sub max/; (2) Na/sup +/ activation was inhibited noncompetitively by V, as evidenced by a decrease in V/sub max/ and no change in K/sub m/; (3) K/sup +/ activation was inhibited by V with a decrease in both V/sub max/ and K/sub m/; (4) noncompetitive inhibition of Mg/sup 2 +/-ATPase by V was observed; and (5) the kinetic behavior of (/sup 3/H)ouabain binding inhibition by V with respect to ATP and Na/sup +/ activation was mixed and noncompetitive, respectively.

• Research Organization: Univ. of Mississippi Medical Center, Jackson
• OSTI ID: 5704899
• Journal Information: J. Toxicol. Environ. Health; (United States), Journal Name: J. Toxicol. Environ. Health; (United States) Vol. 8:3; ISSN JTEHD
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACID ANHYDRASES
ALKALINE EARTH ISOTOPES
ANIMALS
ATP-ASE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BODY
BRAIN
CALCIUM 45
CALCIUM ISOTOPES
CENTRAL NERVOUS SYSTEM
DAYS LIVING RADIOISOTOPES
ELEMENTS
ENZYME ACTIVITY
ENZYME INHIBITORS
ENZYMES
EVEN-ODD NUCLEI
HYDROLASES
IN VITRO
INTERMEDIATE MASS NUCLEI
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
METALS
NERVOUS SYSTEM
NUCLEI
ORGANS
PHOSPHOHYDROLASES
RADIOISOTOPES
RATS
RESPONSE MODIFYING FACTORS
RODENTS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TRITIUM COMPOUNDS
VANADIUM
VANADIUM COMPOUNDS
VERTEBRATES