Caffeine - a good or a bad thing?
Although caffeine is not classed as a neurotransmitter, it does however have a great influence on neurotransmitter activity.
The inhibitory neurotransmitter adenosine has specific receptors in the synaptic cleft, and caffeine has been shown to bind to these receptor sites, blocking adenosine activity. This results in the speeding up of neurotransmitter transmission, causing a surge of noradrenaline, dopamine and serotonin, which if not already high, can improve mood. It also boosts levels of acetylcholine, a neurotransmitter that improves short-term memory.
Adenosine levels in the brain increase during the day and are especially high in the elderly.
Caffeine also raises the adrenal hormone cortisol, which is useful if your cortisol levels are generaly low as you can gain a welcomed energy boost. However, if you are suffering from stress and your cortisol levels are already high, or if your adrenal glands are fatigued, caffeine will make your symptoms worse. In this situation you need to remove all stressors and stimulants and rest the adrenal glands.
Consuming too much caffeine earlier in the day or during short periods of time can deplete neurotransmitter supplies faster than they can be made. This results in mental exhaustion and fatigue. Spreading out and moderating caffeine intake can help even out these mood swings, especially later in the day.
The constant release of noradrenaline depletes its precursor phenylalanine, causing the caffeine let down which many people experience later on. Taking L-phenylalanine, and the other noradrenaline precursors, can help to achieve sustained energy levels throughout the day. Caffeine has also been shown to reverse some of the performance-impairing effects of ethanol (alcohol).
Restlessness - nervousness - excitement - insomnia - flushed face - increased urinary output - gastrointestinal disturbances - muscle twitching - talking or thinking in a rambling manner - disturbances of heart rhythm - periods of inexhaustibility - feelings of being overdriven.