THE ADEQUACY OF THE CHEMICAL THEORY OF SMOOTH MUSCLE EXCITATION

Abstract

The action of yohimbine, 933F, cocaine and adrenine on the electric and mechanical responses of the nictita- ting membrane and tail pllomotors of the cat to stimulation of their sympathetic nerve supply is described. The effects of chronic preganglionic denervation of the nictitating membrane on its electric and mechanical responses are reported. The influence of 929F on the inhibition of gastric peristalsis by adrenine and splanchnic stimulation is analyzed. It is concluded that certain substances (e.g., cocaine and adrenine) and chronic decentralization depolarize smooth muscle, rendering it more permeable, while other substances (e.g., yohimbine and 933F) increase the polarization and decrease the permeability; that there is no electric transmission of the nerve impulses to smooth muscle; and that the theory of chemical mediation accounts satisfactorily for the data available.