<p>Morphological alterations of dopaminergic neurons in the substantia nigra were examined in spontaneously hypertensive rats (SHR) and normotensive Wistar rats. Dopaminergic neurons were identified by immunohistochemical staining for tyrosine hydroxylase. The study revealed a detrimental effect of arterial hypertension on the integrity of dopaminergic neurons in the substantia nigra. The number of neurons exhibiting signs of degeneration in the substantia nigra of SHR was significantly higher than that in control Wistar rats. These findings suggest a potential role of arterial hypertension in the pathogenesis of neurodegeneration in the substantia nigra.</p>