# Tachykinins--IBS, asthma & bladder problem link?



## SteveE (Jan 7, 1999)

: Neuropeptides 2000 Oct;34(5):303-313 Related Articles, Books Peripheral actions of tachykinins.Lecci A, Giuliani S, Tramontana M, Carini F, Maggi CAPharmacology Department, Menarini Ricerche, Florence, Italy[Record supplied by publisher]Tachykinins mediate a variety of physiological processes in the gastrointestinal, pulmonary and genito-urinary tract mainly through the stimulation of NK1 and NK2 receptors. Preclinical evidence obtained through the use of selective tachykinin receptor antagonists indicates that endogenous tachykinins are involved in augmented smooth muscle contraction, vasodilatation, chemotaxis and activation of immune cells, mucus secretion, water absorption/secretion. Recent evidence also suggests that endogenous tachykinins released at the peripheral level may play a role in visceral inflammation, hyperreflexia and hyperalgesia. Possible mechanisms underlying the stimulation of primary afferent neurons by tachykinins may involve a direct excitation of these neurons and the release of mediators which sensitise or stimulate sensory nerves. Tachykinin receptor antagonists could have a clinical utility in several human diseases such as irritable bowel syndrome, asthma, and in micturition disturbances characterized by a hyperactive bladder. Copyright 2000 Harcourt Publishers Ltd


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## Mike NoLomotil (Jun 6, 2000)

Tachykinins are a type of peptide-neurotransmitter and in humans these are Substance P, Neurokinin A, Neurokinin (or Neuromedin







. In infection or trauma they are associated with the release of proinflammatory cytokines especially TNF-alpha. They are like a "messenger" (neurotrnamitter) in inflammatory reactions.Back in 1997 (or earlier) someone did a study on isolated human bladders showing that each of these tachykinins (S-P;NKA;NKB) elicited contractile responses in isolated human bladders (ie: this can be associated with the experience of "urinary frequency" should a response elicit reactions through pathways involving the tachykinins). They were also found independently to facilitate tissue immune cell reactions (mast cells) including those in the gut and the bronchial wall.Also interesting in that they are chemically related to pepetides found in certain foods which have been shown to elicit the same inflammatory-type reactions. Some of the foods known to contain "mast cell eliciting peptides" are shellfish, strawberries, pork, egg white, tomatoes, chocolate an alcohol.They sort of serve as another indicator, in this case another form of nuerotransmitter, showing the interesting complete cross-connection of the neuroimmune system and the viscera, and how anything which elicits an intravascular or tissue inflammatory reaction can elicit visceral symptoms throughout the body.Some work has been done with tachykinin receptor agonists including using a bacterial toxin to destroy the sensory nerve endings which elicit responses involving tachykinins. I think they were able to show that TNF-alpha release was attentuated but not interleukins (but only 2 specific interleukins were looked at). That was few years ago but I do not think I have seen anyone attacking IBS pharmacotherapy from this direction, even though the information is there which shows the "connectivity".MNK_______________ www.leapallergy.com [This message has been edited by Mike NoLomotil (edited 10-30-2000).]


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## moldie (Sep 25, 1999)

Very interesting Steve and Mike.


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