The effect of denervation on the synchronization of contraction of the rat vas deferens

Abstract

Denervation of the rat vas deferens results in both quantitative and qualtitative changes in the contraction of the isolated smooth muscle. The maximum contraction induced by norepinephrine, acetylcholine or serotonin is enhanced by denervation. The response of the tissue to 2 X 10(-4) M BaCl2 initiates a contraction which is more synchronized than the response of the control tissue. By use of 14C-sorbitol and Co-EDTA for estimating extracellular space and from fluorescence histochemical observations, it appears that facilitation of drug diffusion through the extracellular space plays an unimportant role in the altered response to drugs. In experiments which utilized a double-compartment tissue bath it was found that denervation enhanced the propagation of the contraction in the longitudinal direction. From measurements of the longitudinal tissue impedance it was determined that the resistance between smooth muscle cells was significantly decreased by denervation. These results suggest that denervation improves the propagation of excitation in this smooth muscle.