View source for Neurokinin A

{{infobox protein
| Name=[[TAC1|TAC1 tachykinin, precursor 1]]
| caption=[[Protein nuclear magnetic resonance spectroscopy|Solution structure]] of the tachykinin peptide neurokinin a in the presence of [[micelle]]s.<ref name="pmid14645089">{{PDB|1N6T}}; {{cite journal |vauthors=Chandrashekar IR, Cowsik SM | title = Three-dimensional structure of the mammalian tachykinin peptide neurokinin A bound to lipid micelles | journal = Biophys. J. | volume = 85 | issue = 6 | pages = 4002–11 |date=December 2003 | pmid = 14645089 | pmc = 1303701 | doi = 10.1016/S0006-3495(03)74814-0 | url = | issn = }}</ref>
| image= Neurokinina.png
| width=
| HGNCid=11517
| Symbol=[[TAC1]]
| AltSymbols=TAC2, NKNA
| EntrezGene=6863
| OMIM=162320
| RefSeq=NM_013998
| UniProt=P20366
| PDB=
| ECnumber=
| Chromosome=7
| Arm=q
| Band=21
| LocusSupplementaryData=-q22
}}
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 434793565
| ImageFile=Neurokinin A.png
| ImageSize=250px
| IUPACName=
| OtherNames=
|Section1={{Chembox Identifiers
| IUPHAR_ligand = 2089
| CASNo_Ref = {{cascite|correct|??}}
| CASNo=86933-74-6
| PubChem=55582
| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}
| ChemSpiderID = 4470818
| SMILES = C[C@H]([C@@H](C(=O)N[C@@H](CC(=O)O)C(=O)N[C@@H](CO)C(=O)N[C@@H](Cc1ccccc1)C(=O)N[C@@H](C(C)C)C(=O)NCC(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCSC)C(=O)N)NC(=O)[C@H](CCCCN)NC(=O)[C@H](Cc2cnc[nH]2)N)O
| InChI = 1/C50H80N14O14S/c1-26(2)18-34(45(73)58-32(42(53)70)15-17-79-6)57-38(67)23-55-49(77)40(27(3)4)63-47(75)35(19-29-12-8-7-9-13-29)60-48(76)37(24-65)62-46(74)36(21-39(68)69)61-50(78)41(28(5)66)64-44(72)33(14-10-11-16-51)59-43(71)31(52)20-30-22-54-25-56-30/h7-9,12-13,22,25-28,31-37,40-41,65-66H,10-11,14-21,23-24,51-52H2,1-6H3,(H2,53,70)(H,54,56)(H,55,77)(H,57,67)(H,58,73)(H,59,71)(H,60,76)(H,61,78)(H,62,74)(H,63,75)(H,64,72)(H,68,69)/t28-,31+,32+,33+,34+,35+,36+,37+,40+,41+/m1/s1
| InChIKey = HEAUFJZALFKPBA-JPQUDPSNBV
| StdInChI_Ref = {{stdinchicite|changed|chemspider}}
| StdInChI = 1S/C50H80N14O14S/c1-26(2)18-34(45(73)58-32(42(53)70)15-17-79-6)57-38(67)23-55-49(77)40(27(3)4)63-47(75)35(19-29-12-8-7-9-13-29)60-48(76)37(24-65)62-46(74)36(21-39(68)69)61-50(78)41(28(5)66)64-44(72)33(14-10-11-16-51)59-43(71)31(52)20-30-22-54-25-56-30/h7-9,12-13,22,25-28,31-37,40-41,65-66H,10-11,14-21,23-24,51-52H2,1-6H3,(H2,53,70)(H,54,56)(H,55,77)(H,57,67)(H,58,73)(H,59,71)(H,60,76)(H,61,78)(H,62,74)(H,63,75)(H,64,72)(H,68,69)/t28-,31+,32+,33+,34+,35+,36+,37+,40+,41+/m1/s1
| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}
| StdInChIKey = HEAUFJZALFKPBA-JPQUDPSNSA-N
| MeSHName=Neurokinin+A
  }}
|Section2={{Chembox Properties
| Formula=C<sub>50</sub>H<sub>80</sub>N<sub>14</sub>O<sub>14</sub>S
| MolarMass=1133.32
| Appearance=
| Density=
| MeltingPt=
| BoilingPt=
| Solubility=
  }}
|Section3={{Chembox Hazards
| MainHazards=
| FlashPt=
| AutoignitionPt =
  }}
}}
'''Neurokinin A''', formerly known as Substance K, is a neurologically active peptide translated from the pre-protachykinin gene.<ref name="n4"/>  Neurokinin A has many excitatory effects on mammalian nervous systems and is also influential on the mammalian inflammatory and pain responses.<ref name="n23"/>

== Introduction ==
Neurokinin A (formally known as substance K) is a member of the [[tachykinin]] family of neuropeptide neurotransmitters. Tachykinins are important contributors to [[nociceptive]] processing, satiety, and smooth muscle contraction.  Tachykinins are known to be highly excitatory neurotransmitters in major central neural systems.<ref name="n23"/>  Neurokinin A is ubiquitous in both the central and peripheral mammalian nervous systems, and seems to be involved in reactions to pain and the inflammatory responses. It is produced from the same [[preprotachykinin A]] gene as the neuropeptide [[substance P]].  Both substance P and neurokinin A are encoded by the same mRNA, which when alternatively spliced can be translated into either compound.<ref name="n4"/> It has various roles in the body of humans and other animals, specifically stimulation of extravascular smooth muscle, vasodilation, hypertensive action, immune system activation, and pain management. The deduced amino acid sequence of neurokinin A is as follows:<ref>{{cite journal|last1=Severini|first1=C|last2=Improta|first2=G|last3=Falconieri-Erspamer|first3=G|last4=Salvadori|first4=S|last5=Erspamer|first5=V|title=The tachykinin peptide family.|journal=Pharmacological Reviews|date=June 2002|volume=54|issue=2|pages=285–322|pmid=12037144|doi=10.1124/pr.54.2.285}}</ref> 
* [[Histidine|His]] [[Lysine|Lys]] [[Aspartic acid|Asp]] [[Serine|Ser]] [[Phenylalanine|Phe]] [[Valine|Val]] [[Glycine|Gly]] [[Leucine|Leu]] [[Methionine|Met]] (HKTDSFVGLM)
with amidation at the C-terminus.

== Mechanism of action ==
[[File:NeuroKininA Mechanism.jpg|thumb|250px]]
Modified from: Sun J, Ramnath RD, Tamizhselvi R, Bhatia M."Neurokinin A engages neurokinin-1 receptor to induce NF-kappaB-dependent gene expression in murine macrophages: implications of ERK1/2 and PI 3-kinase/Akt pathways." Am J Physiol Cell Physiol. 2008 Sep;295(3):C679-91

Like Substance P [SP], Neurokinin A is present in excitatory neurons and secretory cells of the [[hypothalamic–pituitary–adrenal axis]].<ref name="n5"/>  Additionally both SP neurokinin A is found in the neurosensory system and modulates a wide range of inflammatory and tissue repairing processes [http://www.nature.com/jid/journal/v117/n5/full/5601252a.html]. In various tissues, such as the skin, the release of bioactive tachykinins by sensory nerve fibers C, that extend from the [[dorsal root ganglia]] into the epidermis, directly influence the activity of [[keratinocytes]].<ref name="n18"/>  Inflammation, tissue healing and cell proliferation have been linked to both SP and neurokinin A release into surrounding tissues.

===Nervous system===
The overstimulation of the hypothalamic–pituitary–adrenal axis system and elevated secretion of [[corticotropin-releasing hormone]] from the hypothalamus,  have been studied in many clinical manifestations of pathological depression.<ref name="n5"/>  Studies have shown that stress-induced activation of the noradrenergic [[noradrenergic|prefrontal lobe]] system may be under the control of both endogenously released corticotrophin-releasing hormone and SP and neurokinin A.  This study directly links the secretion of neurokinin A and SP to certain forms of depression characterized by the corticoid receptor hypothesis of depression.<ref name="n6"/>

Inflammatory responses within the central nervous system (CNS) are often the result of traumatic injury or exposure to infectious agents.<ref name="n16"/> Inflammation provides a protective immune response to such stresses may also result in progressive damage to the CNS.  There is significant evidence to indicate that tachykinins are a major component of the neural inflammatory response at peripheral tissues as well as the CNS.<ref name="n16"/> The ability to regulate tachykinin secreation represents an important mechanism for designing potentially useful drugs to treat inflammation. Neurokinin A has been associated with the chemokines [[interleukin-1]] and [[interleukin-6]], both of which are heavily involved in the inflammatory process during infections.<ref name="n16"/>

Neuronal tissue can be severely damaged either through physical trauma or intracellular stresses, either chronic or acute. Either of these scenarios can result in calcium overload, protein degradation, the unfolded protein response or an accumulation of DNA damage.<ref name="n16"/> Endogenous cellular responses are activated within neurve tissue in response to damage in order to protect cellular, protein, and nucleic acid integrity. A large variety of neuroprotective signaling mechanisms exist, which can be manipulated by drugs to reduce damage from cellular damage in neurons.  Tachykinins thus have a number of neuroprotective physiological roles in medical conditions <ref name="n16"/>

===Immune system===
The immune system is a highly integrated system which receives input from many sources, such as sites of injury, [[nocireceptors]] and white blood cells.  Chemical signals therefore are an important component of paracrine, autocrine and endocrine signaling.  
Neurokinin A was shown to be a potent chemo attractor for [[T cells|T-cells]] increasing the migration into infected tissues.<ref name="n8"/>  This migration is necessary for the pathogen seeking activity of T-cells.  Some chemokines trigger the intravascular adhesion of T-cells whereas others direct the migration of [[leukocytes]] into and within the extravascular space.  Since lymphocytes must be positioned correctly to interact with other cells, the pattern of chemokine receptors and the type and distribution of chemokines in tissues critically influence immune responses.<ref name="n10"/>  The molecular mechanism behind neurokinin's role as a chemoattractor is currently unclear.

Neurokinin A has an inhibitory effect on the formation of [[myeloid cells]], and appear to be involved in one specific receptor since the effect can be completely abolished by a NK-2 receptor-selective antagonist.<ref name="n8"/>  The inhibitory effect of neuronkinin A is countered by the excitatory effect of a structurally similar compound: [[substance P]].<ref name="n8"/>  The opposite effects on myelogenesis by substance P and neurokinin A may represent an important feedback mechanism for maintenance of homeostasis.

===Respiratory system===
The binding of neurokinin A to the NKR-2 results in bronchoconstriction, mucus production in the lungs and process neurogenic inflammation.<ref name="n9"/>  This release is propagated through the stimulation of e-NANC nerves in the bronchial epithelium via an axon-reflex mechanism.

===Cardiovascular system===
Neurokinin has been shown to contribute to both bradycardia and myocardial infarctions through the activation of NK2 receptors.<ref name="n13"/>
The dual sensory-motor function of neurokinin A containing afferent neurons is a component of the intracardiac nervous system.<ref name="n20"/> Varicose processes of tachykinin-containing nerves are abundant in coronary arteries and in the cardiac ganglia.  The diverse responses that are triggered by locally released tachykinins produce beneficial effects such as modulation of ganglion transmission.<ref name="n20"/>  However, it is also possible that excessive stimulation of cardiac afferents and release of tachykinins, during pathological conditions such as myocardial infarction, could contribute to certain human pathologies.<ref name="n20"/>

==Receptor==
[[File:NeurokininInflamationPathway.png|thumb|250px|'''Mechanism of neukoinin induced neurogenic inflammation. Neuropeptides are released from C-fibers due to nervous tissue stress and induce many cellular pathways''']]
Tachykinins selectively bind and activate the [[G-protein coupled receptors]] NK1R, NK2R, and NK3R.<ref name="n5"/>  Neurokinin A binds to the G-protein coupled receptor ultimately increasing the release of inositol-phosphate and calcium second messengers.<ref name="n7"/>  Each receptor demonstrates a specific affinity for either neurokinin A or substance P peptides.  Both peptides, however, can act as full agonists on either receptor, although their potency is decreased when not bound to their specific receptor.<ref name="n16"/>

===NK-2 receptor===
NK-2 receptors are expressed predominantly in the CNS.  Networks involved in emotional processing, such as the prefrontal cortex, cingulate cortex, and amygdala, show the highest concentration of NK-2 receptors.<ref name="n14"/><ref name="n19"/>  NK-2 receptor antagonists have been theorized to have antidepressant benefits and are presently in clinical trials.<ref name="n14"/>  As a consequence of its ability to stimulate intestinal smooth muscle, NKA is considered to be specifically active in regulating intestinal motility by its action on NK2 receptors.<ref name="n21"/>

====Antagonists====
'''MEN 11420''' has been demonstrated to be a potent, selective and competitive antagonist of tachykinin NK2 receptors, both in animal and human models. In vivo animal models, MEN 11420 produces an effective and long-lasting blockade of the NK2 receptors expressed in the smooth muscle of the intestinal, genito-urinary and respiratory tract.<ref name="n21"/>

== History ==
Neurokinin A was isolated from porcine spinal cord in 1983 by von Euler and Gaddum.<ref name="n11"/>

==Structure==
Tachykinis are a structurally related group of neuropeptides sharing the C-terminal sequence '''Phe-X-Gly-Leu-Met-NH2'''.<ref name="n5"/>  The amino acid sequence of substance P and neurokinin A are well conserved across mammals species.<ref name="n16"/>  Structure of mammalian neurokinin A was obtained using CD spectropolarimetry and 2D proton NMR.<ref name="pmid14645089"/>  Analysis showed that in water, the peptide adopts an extended conformation while in the presence of [[micelle]]s (a model [[cell membrane]] system), an [[alpha helix|alpha helical]] conformation is induced in the central core (Asp4-Met10).<ref name="pmid14645089"/>

===Genetic overview===
The ''pre-protachykinin-1'' and ''pre-protachykinin-2'' genes in mice encode four very distinct peptides with varying physiological function.<ref name="n5"/>  Alternative splicing of the ''pre-protachykinin-1'' gene gives rise to four different peptide precursors(''alpha''tac1, ''beta''tac1, ''delta''tac1 und ''gamma''tac1), which are further processed into several related peptides including neurokinin A and substance P.<ref name="n5"/>  The ''alpha tac1'' and ''beta tac1'' precursors encode synthesis of both Substance P and neurokinin A.<ref name="n5"/>

[[File:PreProtoTachykininASplicing.png|thumb|250px]]
Modified from:Nakanishi, Shigetada. "Molecular Mechanisms Of Intercellular Communication In The Hormonal And Neural Systems." IUBMB Life 58.5/6 (2006): 349-357

====Mouse models====

''pre-protachykinin-1 -/-'' mice show normal fertility and behavioral patterns (litter-mate socialization and pup rearing), but have a reduced sense of anxiety when threatened, compared to both wild-type mice and other mouse models of depression.<ref name="n5"/>

== Applications ==

===Cancer===
Circulating concentrations of neurokinin A is an independent indicator of poor prognosis in certain cancers such as carcinoids.<ref name="n17"/> Patients presenting with neurokinin A plasma concentrations of >50 pmol/l showed a poorer 3 year survival rate than patients presenting with neurokinin A concentrations of less than 50 pmol/l.<ref name="n17"/>  These types of studies show that measuring tachykinin levels in human patients may have clinical relevance.

Patients with Midgut [[Carcinoid]] disease (MGC) commonly receive neurokinin A test to determine the progression of their disease.  Midgut Carcinoid disease  is an uncommon disease with occurrence rates of approximately 1.4 per 100,000 of the population per year.<ref name="n17"/>  MGC has an unpredictable disease progression depending on the patient, symptoms and progression range from rapid and aggressive to chronic.<ref name="n17"/>  Treatment is difficult because of the varying degrees of severity, so assessing the extent of the disease is extremely important in effective treatment.

===Asthma===
The blocking of neuropeptide signaling has come become a novel therapeutic target for suppression of bronchial constriction in asthma patients.<ref name="n9"/>

Bronchoconstriction is among the most prominent and extensively studied effects caused by tachykinins. Tachykinins have numerous effects in the respiratory systems especially in asthma patients who are more responsive to tachykinin administration.<ref name="n12"/>  Through studies with human airways researchers have examined the role tachykinins play in bronchoconstriction, most notably through the receptor NK2, though regulation of NK2 receptors seems to be mediated by the activity of NK1 receptors eluting to complicated inhibition mechanism.<ref name="n12"/>
Administration of DNK333 (a dual tachykinin receptor NK1/NK2 antagonist) have shown protective activity against neurokinin A induced bronchoconstriction.<ref name="n12"/>

===Psychiatric disorders===
Neurokinin A is involved in many stress induced neurological disorders, such as depression, schizophrenia and epilepsy.<ref name="n14"/>

====Affective disorders====
Affective disorders are characterized by a frequent, fluctuating alteration in mood, affecting the patient’s thoughts, emotions, and behaviors. Affective disorders include depression, anxiety, and bipolar disorder.<ref name="n16"/> A number of approaches have been utilized to study the role that neurokinin A plays in the manifestation and continuation of human affective disorders.<ref name="n16"/> The measurement of serum peptide levels in depressed patients as well as anxious patients displayed higher plasma levels of tachykinins than their low-anxiety counterparts.<ref name="n16"/> In addition to studies of plasma levels of TKs, cerebrospinal fluid (CSF) levels of neurokinin A have also been directly correlated with depression.<ref name="n16"/> Under states of depression, neurokinin immunoreactivity is increased in the frontal cortex, and decreased in the striatum. These peptide levels were not found to be normalized by lithium treatment in mice.<ref name="n14"/>  Elevated levels of tachykinins in CSF have been found in patients with fibromyalgia syndrome, a disorder that is strongly correlated with depression in human patients.  Tachykinin ligands have been extensively studied and determined to be functionally linked to the control of affective phenotypes in a complex physiological manner.

====Epilepsy====
Epilepsy is a broad category of disorders with varying types of severity and presented symptoms.  Neurokinins have been experimentally determined as possible predictor in the generation of certain forms of epilepsy.<ref name="n16"/>  Experimentally when substance P is injected into the rat hippocampus, it significantly lowers the initiation threshold for seizures induced in a dose-dependent manner.<ref name="n16"/>  Experimental data thus has indicated a pro-convulsant role for the ''Pre-protachykinin-1'' gene and thus substance P and neurokinin A.

==Further reading==
* [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1910324/pdf/brjpharm00194-0248.pdf NCBI]
* [http://ajplung.physiology.org/content/294/3/L523.full.pdf+html AJPLUNG]
* [http://www.sciencedirect.com/science/article/pii/S0091305710003552 Science Direct]
* [http://www.jimmunol.org/content/175/10/6802.full.pdf+html Journal of Immunology]

== References ==
<references>
<ref name="n4">{{cite journal | last1 = Nakanishi | first1 = Shigetada | year = 2006 | title = Molecular Mechanisms Of Intercellular Communication In The Hormonal And Neural Systems | url = | journal = IUBMB Life | volume = 58 | issue = 5/6| pages = 349–357 | doi=10.1080/15216540600746385 | pmid=16754330}}</ref>
<ref name="n5">{{cite journal | last1 = Zimmer | first1 = Andreas | display-authors = etal   | year = 2010 | title = Modulation Of The CRH System By Substance P/NKA In An Animal Model Of Depression | doi = 10.1016/j.bbr.2010.04.044 | journal = Behavioural Brain Research | volume = 213 | issue = 1| pages = 103–108 | pmid=20438764}}</ref>
<ref name="n6">{{cite journal | last1 = Steinberg | first1 = R | last2 = Alonso | first2 = R | last3 = Griebel | first3 = G | last4 = Bert | first4 = L | last5 = Jung | first5 = M | last6 = Oury-Donat | first6 = F | display-authors = etal   | year = 2001 | title = Selective blockade of neurokinin-2 receptors produces antidepressant-like effects associated with reduced corticotropin-releasing factor function | url = | journal = J Pharmacol Exp Ther | volume = 299 | issue = | pages = 449–58 }}</ref>
<ref name="n7">{{cite journal | last1 = Nakanishi | first1 = Shigetada | display-authors = etal   | year = 1990 | title = Tissue Distribution And Quantitation Of The mRNAs For Three Rat Tachykinin Receptors | doi = 10.1111/j.1432-1033.1990.tb19396.x | journal = European Journal of Biochemistry | volume = 193 | issue = 3| pages = 751–757 }}</ref>
<ref name="n8">{{cite journal | last1 = Paige | first1 = Christopher J. | display-authors = etal   | year = 2006 | title = Tachykinins In The Immune System | doi = 10.2174/138945006778019363 | journal = Current Drug Targets | volume = 7 | issue = 8| pages = 1011–1020 }}</ref>
<ref name="n9">{{cite journal | last1 = Kraan | first1 = J. | last2 = Vink-Klooster | first2 = H. | last3 = Postma | first3 = D. S. | year = 2001 | title = The NK-2 Receptor Antagonist SR 48968C Does Not Improve Adenosine Hyperresponsiveness And Airway Obstruction In Allergic Asthma | url = | journal = Clinical & Experimental Allergy | volume = 31 | issue = 2| pages = 274–278 | doi=10.1046/j.1365-2222.2001.00975.x}}</ref>
<ref name="n10">{{cite journal | last1 = Mackay | first1 = Ian R. | last2 = Rosen | first2 = Fred S. | year = 2000 | title = T-Cell Function and Migration — Two Sides of the Same Coin | url = | journal = N Engl J Med | volume = 343 | issue = | pages = 1020–1034 | doi=10.1056/nejm200010053431407 | pmid=11018170}}</ref>
<ref name="n11">{{cite journal | year = 1931 | title =  An unidentified depressor substance in certain tissue extracts| doi = 10.1113/jphysiol.1931.sp002763 | journal = J. Physiol. | volume = 72 | issue = | pages = 74–87 | pmc = 1403098}}</ref>
<ref name="n12">{{cite journal | last1 = Joos | first1 = G.F. | last2 = Vincken | first2 = W. | last3 = Louis | first3 = R. | last4 = Schelfhout | first4 = V.J. | last5 = Wang | first5 = J.H. | last6 = Shaw | first6 = M.J. | last7 = Cioppa | first7 = G.D. | last8 = Pauwels | first8 = R.A. | year = 2004 | title = Dual tachykinin NK1/NK2 antagonist DNK333 inhibits neurokinin A‐induced bronchoconstriction in asthma patients | url = | journal = ERJ | volume = 23 | issue = 1| pages = 76–81 | doi=10.1183/09031936.03.00101902}}</ref>
<ref name="n13">{{cite journal | last1 = Walsh | first1 = David A. | last2 = McWilliams | first2 = Daniel F. | year = 2006 | title = Tachykinins And The Cardiovascular System | url = | journal = Current Drug Targets | volume = 7 | issue = 8| pages = 1031–1042 | doi=10.2174/138945006778019291}}</ref>
<ref name="n14">{{cite journal | last1 = Nagano | first1 = Masatoshi | last2 = Oishi | first2 = Takao | last3 = Suzuki | first3 = Hidenori | year = 2011 | title = Distribution And Pharmacological Characterization Of Primate NK-2 Tachykinin Receptor In The Central Nervous System Of The Rhesus Monkey | url = | journal = Neuroscience Letters | volume = 503 | issue = 1| pages = 23–26 | doi=10.1016/j.neulet.2011.07.057 | pmid=21855604}}</ref>
<ref name="n16">{{cite journal | last1 = Maudsley | first1 = Stuart | display-authors = etal   | year = 2010 | title = The Mammalian Tachykinin Ligand-Receptor System: An Emerging Target For Central Neurological Disorders | url = | journal = CNS & Neurological Disorders - Drug Targets | volume = 9 | issue = 5| pages = 627–635 }}</ref>
<ref name="n17">JES Ardill1, BJ Johnston1, GB Turner1, A McGinty2 & DR McCance1 "Improved Prognosis in Midgut Carcinoid patients by treating raised circulating Neurokinin A (NKA)" ''Endocrine Abstracts'' (2006) 11 OC23
</ref>
<ref name="n18">{{cite journal | last1 = Burbach | first1 = Guido J | last2 = Kyu | last3 = Zivony | first3 = Adam S | last4 = Kim | first4 = Amy | last5 = Aranda | first5 = Jennifer | last6 = Wright | first6 = Stacey | last7 = Naik | first7 = Shubhada M | last8 = Caughman | first8 = S Wright | last9 = Ansel | first9 = John C | last10 = Armstrong | first10 = Cheryl A | year = 2001 | title = The Neurosensory Tachykinins Substance P and Neurokinin A Directly Induce Keratinocyte Nerve Growth Factor | url = http://www.nature.com/jid/journal/v117/n5/full/5601252a.html | journal = Journal of Investigative Dermatology | volume = 117 | issue = 5| pages = 1075–1082 | doi = 10.1046/j.0022-202x.2001.01498.x }}</ref>
<ref name="n19">Norma P. Gerard, Roger L. Eddy, Jr., Thomas B . Shows, and Craig Gerard (1990) [http://www.jbc.org/content/265/33/20455.full.pdf The Human Neurokinin A (Substance K) Receptor.] ''The Journal of Biological Chemistry'' Vol. 2fi.5, No. 33, Issue of November 25. pp.&nbsp;20455–20462</ref>
<ref name="n20">{{cite journal | last1 = Hoover | first1 = Donald B. | last2 = Chang | first2 = Yingzi | last3 = Hancock | first3 = John C. | year = 1998 | title =  Characterization of responses to neurokinin A in the isolated perfused guinea pig heart| url = | journal = Am J Physiol Regul Integr Comp Physiol | volume = 275 | issue = | pages = R1803–R1811 | pmid = 9843869}}</ref>
<ref name="n21">{{cite journal | last1 = Lördal | first1 = Mikael | last2 = Navalesi | first2 = Giovanni | last3 = Theodorsson | first3 = Elvar | last4 = Maggi | first4 = Carlo A | last5 = Hellström | first5 = Per M | date = September 2001 | title = A novel tachykinin NK2 receptor antagonist prevents motility-stimulating effects of neurokinin A in small intestine | url = | journal = Br J Pharmacol | volume = 134 | issue = 1| pages = 215–223 | doi=10.1038/sj.bjp.0704217| pmc = 1572917 }}</ref>
<ref name="n23">{{cite journal | last1 = Schäffer | first1 = Dávid A. | last2 = Gábriel | first2 = Robert | year = 2005 | title = Two Major Tachykinins, Substance P And Substance K, Are Localized To Distinct Subsets Of Amacrine Cells In The Anuran Retina | url = | journal = Neuroscience Letters | volume = 386 | issue = 3| pages = 194–198 | doi=10.1016/j.neulet.2005.06.011 | pmid=16005149}}</ref>
</references>
* {{cite journal | last1 = Sun | first1 = J | last2 = Ramnath | first2 = RD | last3 = Tamizhselvi | first3 = R | last4 = Bhatia | first4 = M | date = Sep 2008 | title = Neurokinin A engages neurokinin-1 receptor to induce NF-kappaB-dependent gene expression in murine macrophages: implications of ERK1/2 and PI 3-kinase/Akt pathways | url = | journal = Am J Physiol Cell Physiol | volume = 295 | issue = 3| pages = C679–91 | doi=10.1152/ajpcell.00042.2008}}
* {{cite journal | last1 = Nishimori | first1 = Toshikazu | display-authors = etal   | year = 2011 | title = Knockdown Of The Tachykinin Neurokinin 1 Receptor By Intrathecal Administration Of Small Interfering RNA In Rats | doi = 10.1016/j.ejphar.2011.09.035 | journal = European Journal of Pharmacology | volume = 670 | issue = 2/3| pages = 448–457 }}

==External links==
* [http://ajplung.physiology.org/content/294/3/L523.abstract Journal]

== Further reading ==
{{refbegin}}
* {{cite journal |vauthors=Maggi C, Patacchini R, Rovero P, Giachetti A |title=Tachykinin receptors and tachykinin receptor antagonists |journal=J Auton Pharmacol |volume=13 |issue=1 |pages=23–93 |year=1993 |pmid=8382703 |doi=10.1111/j.1474-8673.1993.tb00396.x}}
* {{cite journal |vauthors=Regoli D, Boudon A, Fauchére J |title=Receptors and antagonists for substance P and related peptides |journal=Pharmacol Rev |volume=46 |issue=4 |pages=551–99 |year=1994 |pmid=7534932}}
{{refend}}

{{Tachykinins}}
{{Neurokinin receptor modulators}}

[[Category:Peptides]]