This experiment was aimed to investigate the contractile responses of the fermoral artery to the electrical stimulation and the inhibitory effects of verapamil and papaverine on the electrical stimulation of the fermoral artery in the control (n=46) and the diabetic rabbits(n=40). Diabetic rabbits were made by and administration of alloxan (100 mg/kg) intravenously and sacrified 8 weeks later. Femoral arterial rings 3 mm in length were taken and mounted on the force-displacement transducer for the measurements of isometric tension. All experiments were done in the aerated (95% O2 with 5% CO2)biological chamber filled with Kreb's solution and the initial tension of 1.5g was applied to the rings. After 1 hour of equilibrium of the rings, the contractile responses of the electrical stimulation on the femoral arterial rings were taken without vasoactive drugs and then, under verapamil and papaverine solution. And we compared the morphologic findings of the vessels in the two groups in relation to the functional changes by transmission electron miroscopy. The results are as follows: 1. The contractile responses in the presence of verapamil or papaverine solutions to the electrical stimulation were lowed significantly in the fermoral arterial rings of the diabetic rabbits compared with that of the control rabbits (verapamil; 10M~10M: p<0.01, papaverine; 10M & 10M: p<0.01). 2. Transmission electron microphotographs showed many morphological differences of the femoral arteries between the control and the diabetic rabbits. These were irregularities of the internal elastic lamina and the hypertrophy of the cytoplasms of the smooth muscle cells. And also, there were many vacuoles in the cytoplasm of the endothelial cells, lateral to the internal elastic laminaes, and between the smooth muscle cells in the diabetic rabbit femoral artery. By this study, we found that the contractile responses of the femoral arterial rings to the electrical stimulation were decreased in the diabetic rabbits, and the vasodiatory effects of verapamil and papaverine on the electrically stimulated femoral arterial rings were also lowered in the diabetic rabbits compared with the control rabbits. These changes of the vasular responses of the diabetic vessel may be associated with morphological changes manifested by transmission electron microscopy or any other functional derangement of the vessels.
Alloxan ; Arteries ; Cytoplasm ; Electric Stimulation* ; Endothelial Cells ; Femoral Artery ; Hypertrophy ; Microscopy, Electron, Transmission ; Myocytes, Smooth Muscle ; Papaverine ; Rabbits ; Transducers ; Vacuoles ; Vasodilator Agents* ; Verapamil