Parkinson's disease is a movement disorder of the nervous system [1]. The central nervous system consists of the brain and the spinal cord [2]. The central nervous system comprises two basic types of cells:
- Neurons, the nerve cells that transmit and receive signals
- Glia, cells that provide structure in the brain
Damaged nerve cells (neurons) are the cause of Parkinson's
In some parts of the brain, there are many more glia than neurons, but neurons are the main players in the brain [3]. Parkinson's disease is a movement disorder that can lead to problems with movement, tremors, stiffness in the limbs or trunk, or impaired balance as nerve cells (neurons) in parts of the brain weaken, become damaged, or die off [1].
Estimates vary, but currently, the best guess is that our brains contain about 85 billion neurons. A neuron is a nerve cell and is the primary functional unit of the nervous system [4 ].
This is a generic image of a neuron. Neurons actually come in all sorts of shapes and sizes, but this is the prototypical version of a neuron that you often see in a textbook. The structures extending from the left side of a neuron and looking a bit like tree branches are called dendrites [4].
Dendrites are the area where neurons receive most of their information. On dendrites are receptors designed to pick up signals from other neurons in the form of chemicals called neurotransmitters. The signals picked up by dendrites cause electrical changes in a neuron that are interpreted in an area called the soma or cell body. The soma contains the nucleus. The nucleus contains the DNA or genetic material of the cell. The soma takes all the information from the dendrites and consolidates it in an area called the axon hillock. If the signal coming from the dendrites is strong enough, a signal is sent to the next part of the neuron, the axon. At this point, the signal is called an action potential [4].
The action potential travels along the axon, which is covered with myelin, an insulation material that helps prevent the signal from degrading. The final step for the action potential is the axon terminals, also called synaptic boutons. When the signal reaches the axon terminals, it can cause the release of neurotransmitters. These purple structures represent the dendrites of another neuron. When a neurotransmitter is released by the axon terminals, it interacts with receptors on the dendrites of the next neuron, and then the process repeats with the next neuron [4].
LSD promotes the formation of new nerve cells (neurons)
Neurogenesis is the formation of neurons [5]. It is most active during prenatal development but continues throughout adult life to a lesser extent [6]. LSD (lysergic acid diethylamide) is a psychedelic substance known for its hallucinogenic effects [7]. Recent research has shown that LSD can promote neurogenesis, the formation of new nerve cells, in the adult brain [5]. This raises the question of whether LSD could have therapeutic potential for conditions involving neuronal loss, such as Parkinson's disease.
Neuroprotective effects of LSD in animal models
Research in animal models has provided some evidence for the potential neuroprotective effects of LSD. In a study using a rat model of Parkinson's disease, LSD was found to protect against the loss of dopamine-producing neurons, which is a key feature of Parkinson's [8]. Dopamine is a neurotransmitter that plays a crucial role in movement and coordination, and its deficiency is associated with the motor symptoms of Parkinson's disease [9]. The neuroprotective effects of LSD were attributed to its ability to stimulate the expression of a protein called brain-derived neurotrophic factor (BDNF), which supports the survival and growth of neurons [8].
Potential mechanisms underlying LSD's effects
The exact mechanisms by which LSD exerts its neuroprotective effects are not fully understood. However, research has suggested several potential mechanisms:
- BDNF expression: As mentioned earlier, LSD has been shown to stimulate the expression of BDNF, a protein that supports the survival and growth of neurons [8].
- Anti-inflammatory effects: LSD may have anti-inflammatory properties, which could contribute to its neuroprotective effects. Inflammation is implicated in various neurodegenerative disorders, including Parkinson's disease [8].
- Modulation of serotonin receptors: LSD primarily acts on serotonin receptors in the brain. Modulation of these receptors could influence neuronal function and survival [8].
- Enhancement of neural plasticity: LSD may enhance neural plasticity, the ability of the brain to reorganize itself by forming new connections between neurons. This could contribute to the brain's ability to adapt and recover from damage [5].
Challenges and considerations
While the findings from animal studies are promising, it's important to note that translating these results to human applications poses significant challenges. The complexity of neurodegenerative disorders like Parkinson's disease, combined with the unique characteristics of LSD, requires cautious interpretation of the data.
Here are some considerations:
- Species differences: Responses to LSD can vary between species, and what works in a rat may not necessarily work in a human [8].
- Optimal dosage: The effective and safe dosage of LSD for potential therapeutic use in humans needs careful determination to avoid adverse effects [5].
- Long-term effects: The long-term effects of LSD use, especially in the context of neurodegenerative disorders, are not well understood. Further research is needed to assess safety over extended periods.
- Psychedelic effects: The hallucinogenic and psychedelic effects of LSD may pose challenges for its use as a therapeutic agent, particularly in an elderly population.
Conclusion
The potential therapeutic use of LSD in neurodegenerative disorders like Parkinson's disease is an intriguing area of research. While animal studies have shown promising results regarding the neuroprotective effects of LSD, further research is needed to understand the underlying mechanisms and to determine the safety and efficacy of LSD in human subjects.
It's important to approach these findings with caution and recognize the need for rigorous clinical trials before considering LSD as a treatment option for Parkinson's disease. The field of psychedelic research is evolving, and ongoing studies may provide more insights into the therapeutic potential of substances like LSD in the context of neurodegenerative conditions.
