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KMID : 0356619950100020115
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Journal of Korean Society of Endocrinology
1995 Volume.10 No. 2 p.115 ~ p.124
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Effects of Diazoxide, Cromakalim and Pinacidil on acethlcholine and Norepinephrine Release in Rat Hippocampus
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양세훈
김도경/조정구/정진원/최봉규
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Abstract
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It is aim of the present study to gain more insight into the role of KATP-channel in acetylcholine (ACh) and norepinephrine(NE) release in the central nervous system. Slices from the rat hippocampus were equilibrated with [3H]-choline and
[3H]-norepinephrine and the release of the labelled products was evoked by electrical stimulation(3 Hz, 2 ms, 5 VCm-4, rectangular pulses, 2 min), and the influence of KATP-channel openers and other related drugs on the evoked tritium-outflow was
investigated.
Cromakalim, in concentrations ranging from 10 to 300 μM. decreased the evoked [3H]-ACh & [3H]-NE release in a dose-dependent manner without changing the basal rate of release. Diazoxide (10~300μM) inhibited the evoked [3H]-NE release but
increased the
evoked [3H]-ACh release significantly, while, the efects of pinacidil(3~100μM) were vice versa. Glibenclamide(1~30μM), a selective KATP-channel blocker, did not affect the evoked or basal release of both tritium outtlow. And the inhibitory
effect
of
K+ -channel openers was inhibited by glibenclamide pretreatment. Pinacidil-induced increase in the evoked NE release was not affected by cocaine, but potentiated by hydrocortisone, And the diazoxide-induced increase in ACh release was not
affected
by
hydrocortisone pretreatment.
These results suggest that ATP-sensitive K+ -channels are present in the both adrenergic and cholinergic nerve endings of rat hippocampus, but these channels seem to be pharmacologically different from those reported for smooth muscle cells and
pancreatic β-cells(J Kor Soc Endocrinol 10:115~124, 1995).
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KEYWORD
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