[Hemodynamic mechanisms of negative impact of emotional stress on the development of cerebral ischemia in stressor load-sensitive rats].

Emotional stress aggravates the course of brain ischemia that has developed in the presence of the former. The investigation studied the functional state of parietooccipital leptomeningeal anastomoses by vital biomicroscopy, as well as the linear blood flow velocity in the a. cerebri media and a. basilaris by high-frequency (38.5 MHz) Doppler ultrasonography before and after occlusion of the common carotid artery in normal (control) Wistar rats and ones that had experienced 18-hour aggressively conflict emotional stress and that were sensitive to the latter. Hemodynamic differences were found in the rats having a varying sensitivity to the used model of cerebral ischemia. Inadequate collateral blood supply along the circle of Willis was shown when this model of brain ischemia was used in the control animals. It was ascertained that in emotional stress, blood flow considerably reduced in the a. basilaris; the contiguous blood supply area displayed evolving brain edema that compressed leptomeningeal anastomoses and prevented the formation of collateral circulation, followed by occlusion of the common carotid arteries. With this, unilateral occlusion was followed by a short-term reduction in systemic blood pressure (BP) that was not seen in the controls and bilateral occlusion was by the development of collapse. Cerebral blood flow became dependent of systemic BP. The obtained experimental data suggest that it is expedient to include antistressor agents into therapy for chronic cerebrovascular diseases. This is particularly relevant to patients with occlusive carotid artery lesion and Willis circle anomalies since emotional stress may be fatal to them.