ACTION OF STRONTIUM IONS ON THE ISOLATED HEART OF THE RAT AND GUINEA PIG
Addition of 2.1 mM/l Sr/sup ++/ (as SrCl/sub 2/) to the saline solution bathing rat heart progressively lowers the amplitude of contraction, to approximates 15% below normal within 10 min. This inhibition is preceded by a slight, transient stimulation of contraction. Inhibition is reversible if Sr/sup ++/ is removed within 4 to 5 min. In guinea pig heart under the same conditions, Sr/sup ++/ produces greater inhibition; amplitude is reduced 30% after 6 min., without a preliminary positive inotropic effect. If 90% of the Ca/sup ++/ ions in the salt solution are replaced by Sr/sup ++/, Sr/sup ++/ completely compensates for the lowering of Ca/sup ++/ concentration, indicating that it is completely equivalent to Ca in promoting contractility of rat heart muscle. However, in guinea pig heart the tonotropic action of Sr/sup ++/ was proportionally greater than that of Ca/sup ++/. Thus, at low Ca concentrations rat heart is more sensitive to Sr/sup ++/ than guinea pig heart. In the absence of Ca/sup ++/, Sr/sup ++/ stimulntes contraction to such an extent in both species that the excessive tonus practically abolishes heart action. It appears that Sr/sup ++/ cannot totally replace Ca/sup ++/ in the cardiac contractile mechanism. (H.H.D.)
- Research Organization:
- Faculte des Sciences, Paris
- NSA Number:
- NSA-17-005686
- OSTI ID:
- 4751641
- Journal Information:
- Compt. Rend. Soc. Biol., Journal Name: Compt. Rend. Soc. Biol. Vol. Vol: 155
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
Similar Records
Effects of thyroid state on respiration of perfused rat and guinea pig hearts
Species differences in the negative inotropic effect of acetylcholine and soman in rat, guinea pig, and rabbit hearts. (Reannouncement with new availability information)