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Published on: October 18, 2018
Effect of calcium on halothane-depressed beating in heart cells in culture
Insights
The anesthetic halothane reduces heart cell beating intensity and rate by disrupting fast calcium uptake. Increasing calcium levels in the culture medium can reverse these effects on beating intensity and calcium uptake.
Area of Science:
- Cardiology
- Anesthesiology
- Cell Biology
Background:
- * Cultured heart cells exhibit spontaneous, rhythmic contractions.
- * These contractions are influenced by culture conditions.
- * General anesthetics, like halothane, can alter cardiac cell function.
Purpose of the Study:
- * To investigate the effects of halothane on the beating rate and intensity of cultured heart cells.
- * To determine the role of calcium in mediating halothane's effects.
- * To explore the mechanism by which halothane affects myocardial cells.
Main Methods:
- * Cultured heart cells were exposed to varying concentrations of halothane.
- * Calcium concentrations in the growth medium were manipulated.
- * Calcium uptake and release phases (fast and slow) were analyzed.
- * Changes in beating rate and intensity were measured.
Main Results:
- * Halothane decreased both beating intensity and rate in cultured heart cells.
- * Increased extracellular calcium reversed the halothane-induced decrease in beating intensity.
- * Halothane specifically inhibited the fast phase of calcium uptake.
- * Increased extracellular calcium also reversed the halothane-induced inhibition of fast calcium uptake.
- * Halothane's effect on beating rate was not directly linked to calcium metabolism.
Conclusions:
- * Halothane disrupts myocardial cell function, likely by dissolving in cell membranes and impairing membrane function.
- * The anesthetic's impact on beating intensity is primarily mediated through interference with fast calcium uptake.
- * While halothane affects beating rate, the underlying mechanism remains distinct from its effects on calcium metabolism.
Abstract:
Heart cells in culture need no external stimulation to contract; they beat rhythmically at a rate and intensity dependent on culture conditions. These cells respond to the general anesthetic 2-bromo-2-chloro-1,1,1-trifluorethane (halothane), with a loss of beating intensity and a lessening of beating rate. Increased calcium concentrations in growth medium reversed the halothane-depressed beating intensity of heart cells in culture; however, increased calcium concentrations had no effect on the halothane-depressed beating rate. Calcium uptake and release took place in two phases, fast and slow. Only the fast calcium uptake was affected by halothane. Like halothane-depressed beating intensity, the halothane-depressed fast calcium uptake also can be reversed by increased calcium in the growth medium of beating heart cells in culture. Data in this manuscript support the theory that general anesthetics dissolve in membranes and thus disrupt membrane function. The anesthetic halothane appears to affect myocardial beating intensity through its ability to disrupt fast calcium uptake. Halothane also depresses the cardiac beating rate, but the data collected do not relate beating rate with calcium metabolism.
