Experimental intracerebral haemorrhage in normotensive and spontaneously hypertensive rats.

Early changes in intracranial pressure (ICP) and mean arterial blood pressure (MABP) were studied in normotensive and spontaneously hypertensive (SHR) Wistar rats after the development of an experimental intracerebral haemorrhage (ICH). The volume of the ICH was 200 or 400 microliters and they were located in the nucleus caudatus or the subcortical area of the occipital lobe. Our study shows that 200 microliters ICH produced both in normotensive and SHR rats similar mortality rates and ICP changes. However, 400 microliters ICH lead to a significantly higher mortality in SHR rats. The systemic hypertensive response to the increasing of ICP was not observed in SHR animals. Thus, the increase in the cerebral pressure perfusion measured in normal rats does not happen in SHR rats. The cause of this fact in SHR rats could be due to local factors or related to alterations in the peripheral part of the vasomotor reflex.