| Experimental study on the effect of phenobarbital on Na+, K+-activated adenosine triphosphatase in microsome fractions of mouse brain. |
|
Seo Kyu Kim, Sa Jun Chung, Chang Il Ahn |
|
Department of Pediatrics, College of Medicine, Kyung Hee University, Seoul, Korea |
| Phenobarbital 이 생쥐 뇌Microsome 분획내의
Sodium, Potassium-Activated ATPase
활성도에 미치는 영향에 관한 실험적 연구 |
|
김서규, 정사준, 안창일 |
|
경희대학교 의과대학 소아과학교실 |
|
Received: 28 February 1991 • Accepted: 18 April 1991 |
|
|
| Abstract |
|
Na+, K+-activated adenosine triphosphatase (Na+, K+-ATPase) is known to play a role as a trigger
in neurotransmitter release and may also affect the transport of calcium ion (Ca++). By doing so, Na+,
K+-ATPase, as an anticonvulsant, can modify the excitability level of cells in epilepsy. In order to
elucidate the possible mechanisms of neuropharmacological interaction between Na+, K+.ATPase
and phenobarbital, serial experimental studies were carried out.
Na+, K+-ATPase activities were measured in microsome fractions of mouse brain. The measure-
ment of Na+, K+-ATPase was performed using Fiske-Subbarow’s method-the colorimetric determina-
tion of phosphorus, and determination of the protein was made by the method of Lowry and his
colleagues.
Some of the major findings were as follows:-
1) The activity of Na+, K+-ATPase was inhibited by 14.6, 17.7, and 19.8% on average by adding
each phenobarbital 0.01, 0.10, and 1.00 mM. No statistical difference was observed by dosage of the
varying concentrations of phenobarbital.
2) The activity of Na+, K+-ATPase was inhibited by 87.6% by adding ouabain and further addition
of each phenobarbital 0.01, 0.10, and 1.00 mM inhibitied Na+, K+-ATPase by 98.6, 99.9, and 99.9%,
i.e. further inhibition of 11.0, 12.3, and 12.3%. No statistical difference was observed by dosage of
the varying concentrations of phenobarbital
3) The activity of Na+, K+-ATPase was stimulated by 74.7% by adding GABA and further addition
of each phenobarbital 0.01, 0.10, and 1.00 mM inhibited Na+, K+-ATPase activity by 17.7,12.3, and
12.3%. No statistical difference was observed by dosage of the varying concentrations of phenobar-
bital.
4) The mean percentage of inhibition of the activtiy of Na+, K+-ATPase 19.8% by adding
phenobarbital 1.00 mM by further adding of ouabin, Na+, K+-ATPase activity was inhibited by 90.
9%, and 88.4% of enzyme activity was increased by adding GABA. By further adding of phenobar-
bital 1.00 mM, Na+, K+-ATPase activity was inhibited by 20.7%. Therefore, these findings strongly
suggested that phenobarbital had inhibitiory effect on Na+, K+-ATPase activity.
5) By increasing the ratio of Na+, K+, the inhibitory effect of phenobarbital on Na+, K+-ATPase
activity was not changed at the varying concenttations of 20, 40, 80 mM Na in 17 mM K.
6) By increasing the ratio of Na+, K+, the inhibitiory effect of phenobarbital on Na4、K+-ATPase
activity was not changed at the varying concentration of 2, 10, and 17 mM K in 80 mM NaCl.
With the above mentioned results, the following hypothesis can be formulated. Phenobarbital has
a direct inhibitiory effect of Na+, K+-ATPase by which it may increase the influx of Ca ion (Ca++)
by influencing Na+/Ca++ exchange system. Phenobarbital may also act as a trigger for the release of
putative neurotransmitter, and which enhance GABA response by enhancing GABA binding to GABA
receptor or modifying chloride ion channel properties. |
| Key Words:
Phenobarital Na+, K+ -ATPase activry, Mouse brain |
|
PDF Links
Download Citation
