Role of the posterior hypothalamus in the development of acute brain swelling

The cerebrovascular response to norepinephrine: A scoping systematic review of the animal and human literature

Intravenous norepinephrine (NE) is utilized commonly in critical care for cardiovascular support. NE's impact on cerebrovasculature is unclear and may carry important implications during states of critical neurological illness. The aim of the study was to perform a scoping review of the literature on the cerebrovascular/cerebral blood flow (CBF) effects of NE. A search of MEDLINE, BIOSIS, EMBASE, Global Health, SCOPUS, and Cochrane Library from inception to December 2019 was performed. All manuscripts pertaining to the administration of NE, in which the impact on CBF/cerebral vasculature was recorded, were included. We identified 62 animal studies and 26 human studies. Overall, there was a trend to a direct vasoconstriction effect of NE on the cerebral vasculature, with conflicting studies having demonstrated both increases and decreases in regional CBF (rCBF) or global CBF. Healthy animals and those undergoing cardiopulmonary resuscitation demonstrated a dose-dependent increase in CBF with NE administration. However, animal models and human patients with acquired brain injury had varied responses in CBF to NE administration. The animal models indicate an increase in cerebral vasoconstriction with NE administration through the alpha receptors in vessels. Global and rCBF during the injection of NE displays a wide variation depending on treatment and model/patient.

Influence of damage of hypothalamo-hypophysial neurosecretory system and adrenalectomy on the blood-brain barrier alteration during intracranial hypertension

Short-term intermittent cerebral compression following the lesion of NSO, NPV or ME alone or with adrenalectomy, caused disturbances in cerebrovascular system. It was characterized by congestion of blood vessels or vasoparalysis with the damage of BBB. These symptoms were much more pronounced in animals in which ME lesion was combined with adrenalectomy. It seems that the decreased level of vasopressor peptides (VSP, Ox) and catecholamines(A, NA) in the blood could be related to the increased activity of cholinergic system and other substances which are responsible for the dilatation of vessels. It is quite possible that the mutual relation of the above mentioned neuro-humoral factors determine the threshold for cardiovascular and cerebrovascular response to cerebral shock. The breakdown of this threshold could occur at the last stage of intracranial hypertension, being expressed by insufficient control of cardiovascular system with the fall of blood pressure and paralysis of cerebral blood vessels, BBB damage, that eventually might lead to brain death.