Effect of N-feruloyl tyramine (an analogue of tyramine) on inwardly rectifying potassium channel in frog ventricular myocytes

チラミン類縁体N-フェルロイルチラミンによるカエル心室筋内向き整流性カリウムチャンネルに対する影響

Munemori Makoto

Electrophysiological effects of N-feruloyl tyramine (NFT), an analogue of tyramine, on potassium currents in frog ventricular myocytes were examined using single-channel recording and whole-cell voltage clamp technique. Extracellular application of NFT induced a concentration-dependent decrease of macroscopic inward rectifier potassium current (iK1) with ID50 of 198 ,#uM, while tyramine (100 #M) was ineffective in producing an inhibitory effect on iK1. NFT reduced the mean open time of iK1 to 1.3 ms from 3.1 ms in control without affecting the amplitude of single-channel conductance. It is indicated that boi containing NFT produces a prolongation of the plateau phase caused by the suppression of inwardly rectifying K channel. Thus, this prolongation may induce an increase in the inflow of Ca ions, which in turn leads to a positive inotropic effect.

NFT

iK1

Suppression

Medical sciences [ 490 ]

eng

Copyright(c) by Author

Hiroshima J. Med. Sci. Vol.45, No.1, 31-35, March, 1996. HIJM45-5 references

[PMID] 8984103

広島大学