J Korean Neurosurg Soc.  1980 Sep;9(2):387-394.

Kinetic Analysis of Chlorpromazine on Na-K-ATPase Activity of Rabbit Brain Cortex

• Lee GJ
• Lee YW

Abstract

The action of chlorpromazine on Na-K-ATPase activity of rabbit brain homogenate was examined. The results were summarized as the follows: 1. Chlorpromazine inhibited Na-K-ATPase activity in the a dose dependent manner with an estimated I50 of 6s 10(-5)M. 2. Hydrolysis of ATP was linear with time and enzyme concentration with or without cholorpromazine in reaction mixture. 3. Altered pH and activity curves of Na-K-ATPase demonstrated comparable inhibition by chlorpromazine in fuffered acidic, netral and alkaline pH ranges. 4. Kinetic analysis of the effect of chlorpromazine on the various parameters which influence Na-K-ATPase activity revealed that the inhibition was apparently competitive with respect to Na+, and noncompetitive with repect to ATP and K+. Based on these data it is suggested that the inhibition by chlorpromazine is not a consequence of change of affinities of ATP, Mg++ and K+ for the enzyme. Results also indicate that chlorpromazine at the Na+ binding site has an important functional role for the activation of the enzymeby Na+.

MeSH Terms

Adenosine Triphosphate
Binding Sites
Brain*
Chlorpromazine*
Hydrogen-Ion Concentration
Hydrolysis
Adenosine Triphosphate
Chlorpromazine