The Effect of Pheromones on Histamines

Pheromones, taken from the Greek words pherein (to transfer) and hormon (to excite) are chemicals released into the environment by an individual organism as an airborne signal. Although odorless, pheromones have the ability to influence the behavior and physiology of other individuals from the same species when inhaled. Pheromones and their effects have been studied extensively in insects and mammals.

Pheromones in Humans

• The McClintock effect from 1971 proposed that pheromones were present in armpit sweat and could synchronize menstrual cycles. When exposed to her perspiration, the menstrual cycles of women B and C would harmonize with that of woman A. However, the findings came into question due to the methodology used.

  A more recent study found that the brains of homosexual men and heterosexual women responded similarly when exposed to male-identified odors thought to be involved in sexual arousal. The findings suggest that pheromones may play a role in human sexual orientation.

Commercialization of Pheromones

• Body sprays promising to enhance desirability and attractiveness have been marketed since the 1970s. However, the compounds in such sprays ("copulins", "androstenone" and "vomodors") are based on studies carried out on rhesus monkeys. A peer-reviewed study found these substances had no direct influence on human behavior.

  Human pheromones marketing received a boost when a study in 2002 reported that an undisclosed synthetic chemical in a women's perfume increased the wearer's attractiveness to men, possibly through olfactory-mediation. Unfortunately, demonstration of the actual effects was not possible, and the study's methodology was flawed.

What Histamines Are

• Histamines are stored mainly in granules in basophils and tissue mast cells; the latter exists in virtually all body tissues. Upon release from these granules, histamine can produce a number of effects, such as smooth muscle contraction of lung, stomach and uterine tissues; blood vessel dilation to increase permeability and lower blood pressure; increased secretion of gastric acid and heart rate acceleration. Like adrenaline, histamine is also a neurotransmitter that serves to transmit chemical impulses between neurons.

Functions of Histamines

• Mast cells release histamine to mount a hypersensitive reaction to what the immune system perceives to be an antigen, such as pollen. Histamine release isn't a direct effect of antigen challenge; rather, it is released simultaneously with mast cell-released antibodies. The volume of released histamine generates the symptoms of allergic reactions -- runny nose, bronchial constriction, watery eyes and swelling. Histamine also contributes to anaphylaxis, a severe allergic response that can be fatal.

  In injury or infection, histamine allows fluids, leukocytes and blood plasma proteins to migrate to the affected site and begin the healing process.

How Pheromones Affect Histamines

• Theoretically, the immune system may perceive pheromones as antigens and mount an antibody response against them. This could result histamine release from mast cells as in the case of an allergic reaction or infection. However, allergic reactions to compounds secreted or released by the human body are rare.

  Additionally, although researchers have been able to demonstrate the effects of what are apparently pheromones, the chemical structure and their effects on particular outcomes have yet to be fully described, as of June 2010. As such, it is still too early to explain how pheromones can affect the release and effect of histamines.