Effect of sympathetic denervation on smooth muscle cell proliferation in the growing rabbit ear artery

The effect of sympathetic denervation on the uptake of 3H-thymidine (3H-Tdr) into the ear artery of a growing rabbit was studied in vitro and in vivo. Uptake into the right artery was compared with that into the left 2 and 3 weeks after left superior cervical ganglionectomy in 4-week-old rabbits. Denervation was confirmed by the absence of catecholamine fluorescence. The total uptake of 3H-Tdr was determined by scintillation spectrometry, and its distribution in the artery wall was studied by light microscope autoradiography. The denervated ear artery took up significantly less DNA precursor and exhibited fewer labeled vascular smooth muscle cell nuclei in the tunica media than did the control artery. These findings suggest that sympathetic innervation influences the proliferation of vascular smooth muscle in growing rabbits. • During an investigation of the factors affecting arterial smooth muscle cell proliferation, it became desirable to determine whether the sympathetic nervous system influences cell division and growt