Modification of cerebral arterial tone and reactivity by external potassium and magnesium ratio in the dog

摘出脳血管におけるカリウム、マグネシウムイオン比の血管緊張及び収縮反応に及ぼす影響

Modification of cerebral arterial tone and reactivity by external potassium and magnesium ratio in the dog

Creators Murakawa Toshisuke

The interaction of external potassium ([K^＋]_0) and magnesium ([Mg^<2＋>]_0) ions on the vasoconstrictions induced by these cations was investigated in isolated canine middle cerebral and basilar artetial smooth muscle. In addition, the effects of the [K^＋]_0/[Mg^<2＋>]_0 ratio on the reactivity and contractility to serotonin in these cerebral vascular tissues were examined. The results were similar, irrespective of whether helically-cut strips or rings were utilized. [K^＋]_0 was altered over 0-7.1mM/L and [Mg^<2＋>]_0 between 0-4.8mM/L. The results indicate relationship between the concentration of [K^＋]_0 and degree of vasoconstriction produced upon withdrawal of [Mg^<2＋>]_0 was observed over the range of 1-6mM/L [K^＋]_0. As [K^＋]_0 was increased, stepwise, the slow (s-) phase of the contraction became attenuated, while the magnitude of the fast (F-) phase became progressively smaller. Contractions produced by withdrawal of [K^＋]_0 were modified by [Mg^<2＋>]_0 : the higher the [Mg^<2＋>]_0, the less tension upon withdrawal of [K^＋]_0. Contractility to serotonin was depressed when [K^＋]_0 waslowered

[ISSN]0513-1731

[NCID]AN00243156