Histamine is a biologically active molecule that is involved in various physiological processes, including regulation of the immune system, regulation of the digestive system, and regulation of the nervous system. In the nervous system, histamine is a neurotransmitter that is involved in regulating wakefulness, arousal, and attention.
In the body, histamine is released from specialized cells called mast cells in response to various stimuli, such as an allergy-inducing substance or injury. This release of histamine leads to various symptoms, such as itching, redness, and swelling. In the brain, histamine acts on specific receptors to promote wakefulness and alertness.
Histamine levels in the brain can be regulated by drugs called histamine receptor antagonists, also known as antihistamines. These drugs block the action of histamine at its receptors, leading to drowsiness and sedation. Antihistamines are commonly used to treat allergies, but some are also used as sleep aids.
It is important to note that histamine levels can also be affected by other factors, such as stress, illness, and changes in the gut microbiome, and that individual responses to histamine can vary greatly.