Neural Mechanism of Cerebrovascular Atherogenesis in Rats

抄録

As previously reported (Yamori et al: Jap Heart J 18: 544, 1977) a substrain (A₃) of SHRSP developed no cerebrovascular fat deposition under hypertensive condition when bilateral cervical sympathectomy was performed, and a role of neural vascular control in cerebrovascular atherogenesis was suspected by the fluorescence microscopic study which clarified the morphological features, meshwork or ring-like distribution of the cerebrovascular innervation.
In the present study, for further analysis, the effects of denervation on athero-genesis in the cerebrovascular system of normotensive WK with bilateral carotid arteries ligated was investigated. The denervated group revealed siggnficantly lower susceptibility than the control group. Blood pressure, serum cholesterol level, and gain in body weight showed no significant differences between them. Further, fluorescence microscopic study using Evans blue confirmed the coincidence of the richly innervated vascular segments with increased permeability in the vascular wall.
On the other hand, the present study has proven a difference in the effects of denervation on atherogenesis in the cerebrovascular system in various strains of SHRSP. Denervation was the most effective in A₃ strain and the least effective in A₁-sb. The effect in A₄ strain was intermediate between those in A₃ and A₁-sb. This experimental fact is noteworthy, because A₄ substrain was obtained by crossing between A₃ and A₁-sb substrains.
Furthermore, fluorescence microscopic study of the basilar arteries in SHRSP and WK showed the difference in quality of NA terminal or varicosity between SHRSP and WK, i.e., SHRSP revealed larger NA varicosity. This observation suggested high responsiveness of the densely innervated vascular wall in SHRSP. These results reaffirmed the important role of neural control in cerebrovascular atherogenesis and suggested the involvement of a genetic factor, which is partly due to a difference in neural vascular control.