Science has witnessed remarkable advancements over the years, particularly in understanding the complexities of sleep. A notable breakthrough in the middle of the 20th century involved Aaron Lerner and his team of dermatologists who, in 1958, discovered a substance from a bovine pineal gland that could darken the skin of frogs. This substance became known as melatonin, and although its true physiological role in animals remained unknown at the time, it is now commonly referred to as the "sleep hormone."
Today, melatonin is widely recognized as a crucial element in sleep regulation, and it is readily available in the form of pills. However, melatonin is just one piece of the intricate puzzle that governs our sleep-wake cycle. In this article, we dive into the fascinating world of the molecules that influence our sleep and explore how their understanding can impact our daily lives.
Neurons, the building blocks of our nervous system, utilize electrical energy to transmit information through their cell membranes. When interacting with other neurons at synapses, this electrical energy is converted into chemical energy. These chemical messengers, known as neurotransmitters, play a vital role in sleep science.
The cerebral cortex, acting as the main receiver of information from structures beneath it, facilitates communication through ascending and descending transmissions. Ascending transmission occurs when information is sent up towards the cortex, while descending transmission involves relaying information from the cortex to other parts of the body.
Neurotransmitters determine the activating or inhibiting effect of these transmissions. Four types of transmissions exist: ascending and activating, ascending and inhibiting, descending and activating, and descending and inhibiting. Each type serves a specific purpose in regulating our sleep-wake system.
Ascending and activating neurons rely on neurotransmitters such as acetylcholine and glutamate. Acetylcholine is crucial for REM sleep, also known as the dream stage of sleep, and plays a significant role in wakefulness. Glutamate induces fast cerebral-electrical activity, keeping us alert and attentive.
Understanding the intricacies of these neurotransmitters and their role in sleep architecture helps us comprehend why we cannot dream while awake. Different clusters of neurons release acetylcholine, with wakefulness controlled by Wake-On/Rem-Off clusters and dreams overseen by Wake-On/Rem-On clusters. Stimulating the REM-related clusters while awake results in daydreaming or even hallucinations.
Interestingly, nicotine, a substance consumed by many individuals, mimics the effect of acetylcholine in the brain. Therefore, it is advisable to avoid smoking in the evening for a good night's sleep.
In conclusion, the study of molecules involved in sleep neurophysiology has come a long way since the discovery of melatonin. Understanding how neurotransmitters influence our sleep-wake system can greatly impact our everyday lives. By optimizing the delicate balance of these molecules, we can promote healthy sleep patterns and overall well-being.