Electron microscopy study of different diameter and functional purpose mesenterial arteries revealed that spontaneous and DOCA-saline hypertension cause different ultrastructural changes in all coats with the exception of cranial mesenterial artery, in endotheliocytes of which no changes occurred in spontaneous hypertension. In cranial mesenterial artery both forms of hypertension cause disorder of normal media structure while in ramifications-only in spontaneous hypertension. Cranial mesenterial artery loses is properties in both forms of hypertension and in ramifications, in contrast, growth of elastic material is observed. In media of cranial mesentery artery in both forms intercellular space grows smaller, elastic membrane significantly reduces, myocyte layers go closer and despite their hypertrophy, vascular wall thickness does not change in spontaneous hypertension and increases nonsignificantly in DOCA-saline one. For cranial artery ramifications hypertrophy of vascular wall is characteristic. In spontaneous hypertension sympathetic innervation of branches increases, and in saline vasomotor nerves action turns weaker.