EFFECT OF LESIONING OF MEDULLARY CATECHOLAMINE NEURONS OR THE MEDIAN-EMINENCE ON THE DEVELOPMENT OF CEREBRAL VASOSPASM IN THE SQUIRREL-MONKEY

Injections of blood into the interpeduncular fossa and cisterna magna in the squirrel monkey produce an angiographically demonstrable, biphasic cerebral vasospasm with a maximal acute spasm at ten minutes and a maximal late spasm at six days after the subarachnoid haemorrhage (SAH). Selective lesioning of the A 2 nucleus in the medulla oblongata or the median eminence in the hypothalamus prior to the SAH prevents the development of both the acute and late cerebral vasospasm. The present data indicate that the A 2 nucleus and the median eminence participate in the development of vasospasm in the squirrel monkey.