Olney's lesions: Difference between revisions

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'''Olney's lesions''' are a type of [[brain damage]] that has been observed in rodents exposed to certain drugs, such as [[phencyclidine]] (PCP) and other [[dissociative]] drugs. The lesions are named after [[John Olney]], who first reported the phenomenon in 1989.
== Olney's Lesions ==


==History==
[[File:Fnana-07-00023-g002.jpg|thumb|right|Histological image showing Olney's lesions in the rat brain.]]
[[John Olney]] discovered the lesions in 1989 while studying the effects of [[NMDA receptor antagonist]]s. These drugs, which include substances like [[ketamine]], [[phencyclidine]] (PCP), and [[dextromethorphan]] (DXM), were found to cause vacuoles to form in certain regions of the rat brain, particularly the posterior cingulate and retrosplenial cortices.


==Causes==
'''Olney's lesions''' are a type of brain damage that was first observed in laboratory animals by Dr. John Olney in the 1980s. These lesions are characterized by vacuoles, or small cavities, that form in the brain tissue, particularly in the [[cerebral cortex]] and [[thalamus]]. They are associated with the use of certain [[NMDA receptor antagonists]], such as [[dizocilpine]] (MK-801) and [[phencyclidine]] (PCP).
The exact cause of Olney's lesions is not fully understood, but it is believed to be related to the overexcitation of neurons in the brain. This overexcitation can be caused by drugs that block the [[NMDA receptor]], a type of glutamate receptor. When these receptors are blocked, it can lead to an influx of calcium ions into the neuron, which can cause the cell to become overexcited and potentially die.


==Symptoms==
== Pathophysiology ==
The symptoms of Olney's lesions in humans are not well-studied, as the condition has primarily been observed in rodents. However, it is believed that the lesions could potentially cause cognitive deficits, including problems with memory and learning.


==Treatment==
Olney's lesions are believed to result from the blockade of [[NMDA receptors]], which are critical for normal synaptic transmission and [[neuroplasticity]]. When these receptors are inhibited, it leads to a cascade of events that result in the formation of vacuoles within neurons. This process is thought to involve the disruption of normal [[calcium]] homeostasis and the activation of [[apoptotic]] pathways.
There is currently no known treatment for Olney's lesions. The best way to prevent the lesions is to avoid the use of drugs that can cause them, such as [[dissociative]] drugs.


==See also==
== Clinical Significance ==
* [[NMDA receptor antagonist]]
 
* [[Dissociative]]
While Olney's lesions have been extensively studied in animal models, their relevance to humans remains a topic of debate. Some researchers have raised concerns about the potential for similar lesions to occur in humans who use NMDA receptor antagonists, such as [[ketamine]], for recreational purposes or as part of [[anesthetic]] procedures. However, definitive evidence of Olney's lesions in humans is lacking.
 
== Research and Controversy ==
 
Research into Olney's lesions has provided valuable insights into the effects of NMDA receptor antagonists on the brain. However, the topic remains controversial, particularly regarding the implications for human health. Some studies suggest that the doses required to produce Olney's lesions in animals are much higher than those typically used in clinical settings, while others caution against the potential risks of chronic exposure.
 
== Related Pages ==
 
* [[NMDA receptor]]
* [[Neurotoxicity]]
* [[Ketamine]]
* [[Phencyclidine]]
* [[Phencyclidine]]
* [[Ketamine]]
* [[Anesthesia]]
* [[Dextromethorphan]]
 
{{stub}}


[[Category:Neurological disorders]]
[[Category:Neurotoxicity]]
[[Category:Drug-related disorders]]
[[Category:Neurology]]
[[Category:Named medical conditions]]

Latest revision as of 11:58, 15 February 2025

Olney's Lesions[edit]

Histological image showing Olney's lesions in the rat brain.

Olney's lesions are a type of brain damage that was first observed in laboratory animals by Dr. John Olney in the 1980s. These lesions are characterized by vacuoles, or small cavities, that form in the brain tissue, particularly in the cerebral cortex and thalamus. They are associated with the use of certain NMDA receptor antagonists, such as dizocilpine (MK-801) and phencyclidine (PCP).

Pathophysiology[edit]

Olney's lesions are believed to result from the blockade of NMDA receptors, which are critical for normal synaptic transmission and neuroplasticity. When these receptors are inhibited, it leads to a cascade of events that result in the formation of vacuoles within neurons. This process is thought to involve the disruption of normal calcium homeostasis and the activation of apoptotic pathways.

Clinical Significance[edit]

While Olney's lesions have been extensively studied in animal models, their relevance to humans remains a topic of debate. Some researchers have raised concerns about the potential for similar lesions to occur in humans who use NMDA receptor antagonists, such as ketamine, for recreational purposes or as part of anesthetic procedures. However, definitive evidence of Olney's lesions in humans is lacking.

Research and Controversy[edit]

Research into Olney's lesions has provided valuable insights into the effects of NMDA receptor antagonists on the brain. However, the topic remains controversial, particularly regarding the implications for human health. Some studies suggest that the doses required to produce Olney's lesions in animals are much higher than those typically used in clinical settings, while others caution against the potential risks of chronic exposure.

Related Pages[edit]