Editing Redback spider (section)

===Venom===
{{Main|Latrotoxin}}
[[File:Latrodectus hasselti -Sydney, Australia-8.jpg|thumb|right|The distinctive red stripe of the adult female]]
The redback and its relatives in the genus ''Latrodectus'' are considered dangerous, alongside funnel-web spiders (''[[Atrax]]'' and ''[[Hadronyche]]''), mouse spiders (''[[Missulena]]''), wandering spiders (''[[Phoneutria]]'') and recluse spiders (''[[Loxosceles]]'').<ref name="Amo-Redback1">{{cite web | author=Australian Museum | title=Spider Facts | url=https://australian.museum/learn/animals/spiders/spider-facts/ | access-date=20 September 2013 | date=6 May 2013 | archive-date=13 July 2020 | archive-url=https://web.archive.org/web/20200713060040/https://australian.museum/learn/animals/spiders/spider-facts/ | url-status=live }}</ref><ref>{{cite journal|last=Espino-Solis|first=G.P.|author2=Riaño-Umbarila, L. |author3=Becerril, B. |author4= Possani, L.D. |title=Antidotes against Venomous Animals: State of the Art and Prospectives|journal=Journal of Proteomics|date=6 March 2009|volume=72|issue=2|pages=183–99|doi=10.1016/j.jprot.2009.01.020|pmid=19457345|type=Review}}</ref> Venom is produced by [[holocrine]] glands in the spider's [[chelicerae]] (mouth parts).<ref name=Rohou2007>{{cite journal |title=Insecticidal Toxins from Black Widow Spider Venom |date=15 March 2007|journal=Toxicon |volume=49 |pages=531–49 |first1= A |last1=Rohou |first2= J |last2=Nield |first3= Y.A. |last3=Ushkaryov|pmc=2517654 |issue=4–5 |doi=10.1016/j.toxicon.2006.11.021|pmid=17210168 |bibcode=2007Txcn...49..531R |type=Review }}</ref> Venom accumulates in the lumen of the glands and passes through paired ducts into the spider's two hollow fangs.<ref name=Rohou2007/><ref name="NicholsonGraudins"/> The venom of the redback spider is thought to be similar to that of the other ''Latrodectus'' spiders. It contains a complex mixture of cellular constituents, [[enzyme]]s and a number of high-molecular-weight toxins, including insect toxins and a vertebrate [[neurotoxin]] called [[alpha-latrotoxin]], which causes intense pain in humans.<ref name=Rohou2007/><ref name="NicholsonGraudins">{{cite journal|last1=Nicholson|first1=Graham M.|last2=Graudins|first2=Andis|title=Spiders of Medical Importance in the Asia-Pacific: Atracotoxin, Latrotoxin and Related Spider Neurotoxins|journal=Clinical and Experimental Pharmacology and Physiology|volume=29|issue=9|year=2002|pages=785–94|issn=0305-1870|pmid= 12165044| doi=10.1046/j.1440-1681.2002.03741.x|s2cid=12620544|type=Review}}</ref>

In [[vertebrates]], alpha-latrotoxin produces its effect through destabilisation of [[cell membrane]]s and [[degranulation]] of [[nerve|nerve terminals]], resulting in excessive release of [[neurotransmitter]]s, namely [[acetylcholine]], [[norepinephrine]] and [[Gamma-aminobutyric acid|GABA]]. Excess neurotransmitter activity leads to clinical manifestations of envenomation,<ref name="White">{{cite book | editor1 = Meier, J. | editor2 = White, J. | title = Handbook of Clinical Toxicology of Animal Venoms and Poisons | year = 1995 | publisher = CRC Press | url = http://www.toxinology.com/fusebox.cfm?staticaction=generic_static_files/toxdept_crcbook.html | isbn = 0-8493-4489-1 | access-date = 19 October 2021 | archive-date = 12 June 2018 | archive-url = https://web.archive.org/web/20180612141017/http://www.toxinology.com/fusebox.cfm?staticaction=generic_static_files%2Ftoxdept_crcbook.html | url-status = live }}</ref> although the precise mechanisms are not well understood.<ref name=Nimorakiotakis/> Acetylcholine release accounts for neuromuscular manifestations, and norepinephrine release accounts for the cardiovascular manifestations.<ref>{{Cite web|url=http://accessmedicine.mhmedical.com.acs.hcn.com.au/content.aspx?bookid=1658&sectionid=109385845|title=MedicalDirector Login|website=accessmedicine.mhmedical.com.acs.hcn.com.au|access-date=23 October 2017|archive-date=19 October 2021|archive-url=https://web.archive.org/web/20211019062752/https://acs.hcn.com.au/ksLicensing/auth0/institution?redirectURL=http%3A%2F%2Faccessmedicine.mhmedical.com.acs.hcn.com.au%2Fcontent.aspx%3Fbookid%3D1658%26sectionid%3D109385845|url-status=live}}</ref> Female redbacks have an average of around 0.08–0.10&nbsp;mg of venom, and experiments indicate that the [[median lethal dose]] (LD<sub>50</sub>) for mice at room temperature is 10–20% of this quantity (0.27–0.91&nbsp;mg/kg based on the mass of the mice used), but that it is considerably deadlier for mice kept at lower or higher temperatures.<ref name=Wiener1956Temperature>{{cite journal|last=Wiener|first=Saul|title=The Australian Red Back Spider (''Latrodectus Hasseltii''): II. Effect of Temperature on the Toxicity of Venom|journal=The Medical Journal of Australia|date=1 September 1956|volume=43|issue=9|pages=331–34|doi=10.5694/j.1326-5377.1956.tb56713.x|pmid=13368800|s2cid=44645205}}</ref> Pure alpha-latrotoxin has an LD<sub>50</sub> in mice of 20–40&nbsp;μg/kg.<ref>{{cite web|last=Rubin|first=Rebecca L.|title=Redback Spider Envenomation|url=http://emedicine.medscape.com/article/772484-overview#showall|work=Medscape Reference|publisher=WebMD LLC|access-date=16 October 2013|author2=Wiener, Sage W.|date=16 April 2012|archive-date=16 October 2013|archive-url=https://web.archive.org/web/20131016115138/http://emedicine.medscape.com/article/772484-overview#showall|url-status=live}}</ref>

The specific variant of the vertebrate toxin found in the redback was cloned and sequenced in 2012, and was found to be a sequence of 1180 [[amino acid]]s,<ref name=graudins2012>{{cite journal|last=Graudins|first=Andis|author2=Little, Michelle J. |author3=Pineda, Sandy S. |author4=Hains, Peter G. |author5=King, Glenn F. |author6=Broady, Kevin W. |author7= Nicholson, Graham M. |title=Cloning and Activity of a Novel α-latrotoxin from Red-back Spider Venom|journal=Biochemical Pharmacology|date=1 January 2012|volume=83|issue=1|pages=170–83|doi=10.1016/j.bcp.2011.09.024|pmid=22001442|type=Comparative study|hdl=10453/18571|hdl-access=free}}</ref> with a strong similarity to the equivalent molecule across the ''Latrodectus mactans'' clade.<ref>{{cite journal|last=Garb|first=J. E.|author2=Hayashi, C. Y. |title=Molecular Evolution of α-Latrotoxin, the Exceptionally Potent Vertebrate Neurotoxin in Black Widow Spider Venom|journal=Molecular Biology and Evolution|date=21 January 2013|volume=30|issue=5|pages=999–1014|doi=10.1093/molbev/mst011|pmid=23339183|pmc=3670729}}</ref> The syndromes caused by bites from any spiders of the genus ''Latrodectus'' have similarities;<ref>{{cite journal|last=Maretić|first=Zvonimir|year=1983|title=Latrodectism: Variations in Clinical Manifestations Provoked by ''Latrodectus'' Species of Spiders |journal=Toxicon|volume=21|issue=4|pages=457–66|doi=10.1016/0041-0101(83)90123-X|pmid=6353667|bibcode=1983Txcn...21..457M |type=Review}}</ref> there is some evidence there is a higher incidence of sweating, and local and radiating pain with the redback, while black widow envenomation results in more back and abdominal pain,<ref name="jelinek1997">{{cite journal|last=Jelinek|first=George A. |title=Widow Spider Envenomation (Latrodectism): a Worldwide Problem|journal=Wilderness & Environmental Medicine|year=1997 |volume=8|issue=4|pages=226–31|pmid=11990169|doi=10.1580/1080-6032(1997)008[0226:WSELAW]2.3.CO;2|type=Review|doi-access=free}}</ref> and abdominal rigidity is a feature common with bites from the west coast button spider (''[[Button spider|Latrodectus indistinctus]]'') of South Africa.<ref name="lancet"/>

One crustacean-specific and two insect-specific neurotoxins have been recovered from the [[Mediterranean black widow]] (''L. tredecimguttatus''), as have small [[peptide]]s that inhibit [[Angiotensin-converting enzyme|angiotensin-1-converting enzyme]];{{efn|These likely make the venom stronger by altering the victim's physiology.<ref name="vassilevski">{{cite journal|author1=Vassilevski, A. A.|author2=Kozlov, S. A.|author3=Grishin, E. V.|year=2009|title=Molecular Diversity of Spider Venom|journal=Biochemistry (Moscow)|volume=74|issue=13|pages=1505–34|url=http://protein.bio.msu.ru/biokhimiya/contents/v74/pdf/bcm_1505.pdf|doi=10.1134/S0006297909130069|pmid=20210706|s2cid=24572908|access-date=17 November 2013|archive-date=28 September 2010|archive-url=https://web.archive.org/web/20100928080451/http://protein.bio.msu.ru/biokhimiya/contents/v74/pdf/bcm_1505.pdf|url-status=live}}</ref> Angiotensin-converting-enzyme inhibitors, or [[ACE inhibitor]]s, are a class of widely-prescribed medications used in [[hypertension]] and [[heart failure]].<ref>{{cite journal|last=Sweitzer|first= Nancy K. |year=2003|title=What Is an Angiotensin Converting Enzyme Inhibitor?|journal=Circulation|volume=108|pages=e16–18|doi=10.1161/01.CIR.0000075957.16003.07|pmid= 12876137 |issue=3|doi-access=free}}</ref>

}} the venom of the redback, although little-studied, likely has similar agents.<ref name=graudins2012/>{{sfn|Sutherland|Tibballs|2001|p=390}}