Action of Isoproterenol on Heart Cells in Tissue Culture

Trypsin dispersed chick embryo heart cells have been grown in tissue culture to produce rhythmic contraction cell clusters. Isoproterenol, a specific beta adrenergic stimulating drug, has been shown to increase the rate of contraction of these cells. This effect persists for 20-30 minutes and can be removed by washing the cells with fresh control media. Propranolol, a specific beta adrenergic blocking agent, blocks the stimulating action of isoproterenol. It appears likely that stimulation of beta adrenergic receptors of the Ahlquist classification can be used to explain these findings. These receptors apparently develop in the absence of adrenergic nerve endings. Addendum. At a recent symposium on the structure and function of heart muscle. Wollenberger described his unpublished observations (16) on the effects of adrenergic stimulating and blocking drugs on heart cells in tissue culture which are in general agreement with this report.