Editing Cushing reflex (section)

==Research directions==

Although a lot of progress has been made since 1901 when [[Harvey Cushing]] first expanded knowledge of what is now known as the Cushing reflex, there are still many aspects of the research that remain to be seen. The exact [[pathogenesis]] of the disease remains undetermined.<ref name="Fox"/> The possibility that intracranial pressure (ICP) may not be the sole cause of the Cushing reflex per se came from an occurrence of Cushing [[blood pressure]] response occurring before increased ICP.<ref name=Fox /> Some research observed symptoms of Cushing reflex, without the usual increased ICP and medullary [[anemia]], suggesting other causes that still require research.<ref name=Fox />  Axial [[brain stem]] distortion could be the [[pathogenesis]] of Cushing reflex.<ref name=Fox />

The nature of [[Receptor (biochemistry)|receptors]] mediating the Cushing response is also unknown.<ref name=Reis>{{cite journal |vauthors=Reis DJ, Nathan MA, Doba N |title=Two specific brainstem systems which regulate the blood pressure |journal=Clin. Exp. Pharmacol. Physiol. |volume=Suppl 2 |pages=179–83 |year=1975 |pmid=1102170 }}</ref> Some research suggests the existence of intracranial baroreceptors to trigger specific Cushing baroreceptor reflex.<ref name=Schmidt>{{cite book |vauthors=Schmidt EA, Czosnyka Z, Momjian S, Czosnyka M, Bech RA, Pickard JD |title=Intracranial Pressure and Brain Monitoring XII |chapter=Intracranial baroreflex yielding an early cushing response in human |journal=Acta Neurochir. Suppl. |volume=95 |pages=253–6 |year=2005 |pmid=16463859 |doi= 10.1007/3-211-32318-x_51|series=Acta Neurochirurgica Supplementum |isbn=978-3-211-24336-7 }}</ref> Experiments by Schmidt and his fellow researchers showed that the Cushing reflex is directed by [[autonomic nervous system]], since its physiological change has to do with the balance of the [[sympathetic nervous system]] and [[parasympathetic nervous system]].<ref name=Schmidt /> However, the specific relation between the [[autonomic nervous system]] response and the Cushing reflex and its symptoms has yet to be identified.<ref name=Schmidt />

It has been determined that rate of [[Respiration (physiology)|respiration]] is affected by the Cushing reflex, though the respiratory changes induced are still an area that needs more research.<ref name=Grady /> Some researchers have reported [[apnea]], while others have reported increased respiratory rates.<ref name=Grady /> Other researchers have found that increases in respiratory rate follow ICP decreases, while others say it is a response to ICP increase.<ref name=Grady /> One must also take into account the use of [[anesthetics]] in early experimentation.<ref name=Grady /> Research was initially performed on animals or patients under [[anesthesia]].<ref name=Dickinson /> The anesthesia used in experiments have led to respiratory depression, which might have had effect on the results.<ref name=Grady /> Early experiments also put animal subjects under artificial ventilation, only allowing for limited conclusions about respiration in the Cushing reflex.<ref name=Dickinson />  The use of anesthetics proposes ideas for future research, since the creation of the Cushing response has been difficult to create under basal conditions or without anesthesia.<ref name=Dickinson />

Some researchers have also suggested a long-term effect of the Cushing reflex.<ref name=Dickinson /> Thus far it has only been observed as an immediate acute response, but there has been some evidence to suggest that its effects could be prolonged, such as a long-term raise in [[blood pressure]].<ref name=Dickinson /> Heightened sensitivity of neurological response systems leading to arterial hypertension is also possible, but has not been examined.<ref name=Reis />

Although the Cushing reflex was primarily identified as a physiological response when blood flow has almost ceased, its activity has also been seen in [[fetal]] life.<ref name=Dickinson /> This activity has not been thoroughly investigated, so there is a need for more research in this area.

The underlying mechanisms of the reflex on a cellular level are yet to be discovered, and will likely be the next area of research if scientists and or doctors chose to do so.{{cn|date=March 2021}}