The positive chronotropic effects of Bay K-8644 and calcium as influenced by temperature.
The positive chronotropic effects of Bay K-8644 and calcium as influenced by temperature.
复制标题
Bay K-8644 和钙的正变时作用受温度影响。
DOI：
10.1016/0014-2999(86)90369-9
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发表时间：
1986
影响因子：
5
通讯作者：
Kennedy,RH
中科院分区：
文献类型：
--
作者：
Seifen,E;Kennedy,RH
The positive chronotropic effects of the dihydropyridine calcium agonist BAY K-8644 and calcium were studied in spontaneously beating right guinea-pig atria. Within the temperature range from 22 to 37°C, the following observations were made: (1) the basal pacemaker frequency increased linearly with the ambient temperature; (2) the increase in pacemaker rate produced by a maximally effective concentration of BAY K-8644 was of the same magnitude as that produced by calcium; (3) the increases in pacemaker rate produced by BAY K-8644 and by calcium were directly proportional to the increase in temperature above 22°C; and (4) at 37°C, the apparent ED50for the positive chronotropic effect of calcium was 2.3 × 10−3M and of BAY K-8644 was 0.7 × 10−7M. At temperatures below 22°C, irregular pacemaking activity or complete arrest of pacemaking activity frequently occurred. The data are in strong support of the assumption that BAY K-8644 elicits its positive chronotropic effect by increasing the availability of calcium ions.
