[The electrical and contractile activity of denervated smooth muscle]

The effect of norepinephrine, histamine, serotonin and potassium chloride on electrogenesis and contraction was studied on innervated and denervated smooth muscles of cat's nictitating membrane. Denervated smooth muscles generate slow depolarizing potentials with the APs corresponding to tonic and phasic contractions, resp. Tonic contractions occur with no considerable change fo the MP in innervated muscles, phasic contractions being absent. Spontaneous generation of the APs is only possible in denervated muscles. Pharmacomechanical type of coupling between excitation and contraction seems to be characteristic of innervated smooth muscles, whereas electromechanical type is characteristic of denervated muscles. The denervation seems to result not only in the change of cells' sensitivity to transmitters but in the abnormality of coupling processes between excitation and contraction as well.