Histamine works with nerves to produce itching. In food allergies it can cause vomiting and diarrhea. And it constricts muscles in the lungs, making it harder to breathe. Most worrisome is when histamine causes anaphylaxis, a severe reaction that is potentially fatal.
Histamine is a neurotransmitter that is released from histaminergic neurons which project out of the mammalian hypothalamus. The cell bodies of these neurons are located in a portion of the posterior hypothalamus known as the tuberomammillary nucleus (TMN).
Effects of histamine
Histamine is released at the mucosal surfaces as a result of exposure to foreign particles. This histamine release causes the capillaries to become more permeable to white blood cells, which move into the capillaries and proceed to target and attack foreign bodies in the affected tissue.
Histamine is a chemical your immune system releases. It's mainly known for its role in causing allergy symptoms. But it has other important functions, like regulating your sleep-wake cycle and cognitive function. Antihistamines are a common medication that can manage histamine levels.
Histamine is present in many human tissues, including skin, intestinal mucosa, heart, lung, and nerve endings in the brain. The usual body storage sites for histamine include mast cells and basophils (Figure 2).
For these people, histamine builds up in the body and is not broken down correctly. This can trigger an immune system response resulting in symptoms such as diarrhea, shortness of breath, headaches, or skin irritation.
If you have a food allergy, histamines are in on that response process, too. When you accidentally eat or drink something you shouldn't, they'll work in your gut to trigger your allergic reaction. Some foods are also naturally high in histamines. These include aged and fermented foods and alcohol (especially red wine).
Histamine is released from cells in response to an antibody called immunoglobulin E (IgE). This antibody may be secreted in response to an invading pathogen such as a virus, bacteria, or an allergenic substance such as pollen. Histamine can also be released in response to injury caused by toxins.
Brain histamine promotes wakefulness and orchestrates disparate behaviors and homeostatic functions.
Inflammatory mediators are molecules produced by activated cells that intensify and prolong the inflammatory response. Histamine is a potent inflammatory mediator, commonly associated with allergic reactions, promoting vascular and tissue changes and possessing high chemoattractant activity.
Histamine, HTMT, pheniramine, and combination of histamine + pheniramine cause hepatic function impairment in terms of altered serum enzymes and bilirubin levels. The present findings suggest that HTMT causes moderate liver function impairment while others show mild impairment.
Histamine Stimulates Liver OEA Biosynthesis via H1 Receptor Activation To further test this idea, we examined whether pharmacological blockade of histamine receptors affects liver OEA formation.
High levels of histamine can also trigger digestive symptoms like bloating [7], and diarrhea [8], heart rate changes or palpitations [9], low blood pressure [10], and headaches [11].
Histamine may therefore have detrimental effects on renal function. This hypothesis is supported by a number of in vivo studies reported in Table 2.
The level of the histamine metabolite N‐methylhistamine, resulting from the enzymatic activity of HNMT, is higher in the kidney as compared to most other organs (Zimmermann et al., 2011).
Allergens Cause Biochemically Based Fatigue
In addition to immunoglobulin E, the immune system releases a substance called histamine. When both of these substances produce an inflammatory reaction in the body, you may experience a sense of tiredness alongside other, more obvious allergic symptoms.
Too much histamine frequently causes anxiety, panic attacks, and insomnia. There are many potential underlying causes for too much histamine and there is no universal treatment that works for everything.
In the brain, histamine acts as a neurotransmitter which can affect the levels of mood altering neurotransmitters such as GABA, dopamine and serotonin; causing the increased expression of anxious and depressive feelings.
Drinking plenty of water every day is essential for all bodily functions, including the regulation of histamine levels. Water does aid in the removal of histamines from the body as more that 95% of excess histamines are removed from the body through the urine.
Degradation of histamine in gut. (A) Healthy individual. Normal concentration of histamine in food. Most histamine is inactivated by DAO and HNMT enzymes in gut, only a small amount of histamine passes to blood stream and does not cause histamine-mediated symptoms.
Histamine release in the hypothalamus and other target regions was highest during wakefulness. The histaminergic neurons displayed maximal activity during the state of vigilance, and cease their activity during NREM and REM sleep.
What's more, the histamine neurons are generally active in wake states, and inactive during sleep. Histamine neurons promote wakefulness by activating neurons in the cortex that drive arousal and by inhibiting neurons that promote sleep.
Histamine intolerance is more common in people with underlying digestive issues. Conditions such as inflammatory bowel disease, celiac disease, IBS, and SIBO increase the risk of histamine intolerance.