Hola de nuevo.
Desde hace unos años se sabe que las secreciones de las glandulas de Duvernoy de las Thamnophis, además de causar hemorragias (actividad hemotóxica), tiene igualmente, veneno de acción neurotóxica ( three-finger toxin ó 3FTx).
Una caracterización de la toxicidad del veneno de Thamnophis elegans vagrans:
*** CHEMICAL IDENTIFICATION ***
RTECS NUMBER : YX3997000
CHEMICAL NAME : Venom, snake, Thamnophis elegans vagrans
LAST UPDATED : 199109
DATA ITEMS CITED : 1
COMPOUND DESCRIPTOR : Natural Product
SYNONYMS/TRADE NAMES :
* Thamnophis elegans vagrans venom
*** HEALTH HAZARD DATA ***
** ACUTE TOXICITY DATA **
TYPE OF TEST : LD50 - Lethal dose, 50 percent kill
ROUTE OF EXPOSURE : Intraperitoneal
SPECIES OBSERVED : Rodent - mouse
DOSE/DURATION : 13850 ug/kg
TOXIC EFFECTS :
Behavioral - somnolence (general depressed activity)
Lungs, Thorax, or Respiration - dyspnea
REFERENCE :
TOXIA6 Toxicon. (Pergamon Press Ltd., Headington Hill Hall, Oxford OX3 OBW,
UK) V.1- 1962- Volume(issue)/page/year: 19,831,1981
*** END OF RECORD ***
Una caracterización de la toxicidad del veneno de Thamnophis sirtalis parietalis:
*** CHEMICAL IDENTIFICATION ***
RTECS NUMBER : YX3997100
CHEMICAL NAME : Venom, snake, Thamnophis sirtalis parietalis
LAST UPDATED : 199109
DATA ITEMS CITED : 1
COMPOUND DESCRIPTOR : Natural Product
SYNONYMS/TRADE NAMES :
* Thamnophis sirtalis parietalis venom
*** HEALTH HAZARD DATA ***
** ACUTE TOXICITY DATA **
TYPE OF TEST : LD50 - Lethal dose, 50 percent kill
ROUTE OF EXPOSURE : Intraperitoneal
SPECIES OBSERVED : Rodent - mouse
DOSE/DURATION : 33 mg/kg
TOXIC EFFECTS :
Details of toxic effects not reported other than lethal dose value
REFERENCE :
JEZOAO Journal of Experimental Zoology. (Alan R. Liss, Inc., 41 E. 11th
St., New York, NY 10003) V.1- 1904- Volume(issue)/page/year: 233,5,1985
*** END OF RECORD ***
Venom
Garters were long thought to be nonvenomous, but recent discoveries have revealed that they do in fact produce a mild neurotoxic venom.[3] Garter snakes cannot kill humans with the small amounts of venom they produce, which is comparatively mild, and they also lack an effective means of delivering it. They do have enlarged teeth in the back of their mouth, but their gums are significantly larger.[4][5] Whereas most venomous snakes have anterior or forward venom glands, the Duvernoy's gland of garters are posterior (to the rear) of the snake's eyes.[6] The mild venom is spread into wounds through a chewing action. The properties of the venom are not well known, but it appears to contain 3FTx, commonly known as three-finger toxin, which is a neurotoxin commonly found in the venom of colubrids and elapids. A bite may result in mild swelling and an itching sensation. There are no known cases of serious injury and extremely few with symptoms of envenomation.
Extraído de la Wikipedia (
http://en.wikipedia.org/wiki/Garter_snake).
Muscarinic Toxins
Snake venom neurotoxic 3FTx are typically alpha-neurotoxic and this is the ancestral condition, this activity being widespread not only in elapid venoms but also in the venoms of the various 'colubrid' families. However, a number of neurotoxic peptides have been isolated that are active against different postsynaptic receptors or are presynaptically active. Mambas, elapids from Africa, are unique in having a number of toxins targeting other receptors or binding presynaptically. Targets include the muscarinic receptors, the enzyme acetylcholinesterase and potassium channels.
Fuente:
http://www.kingsnake.com/toxinology/snake_neurotoxins.html
[Pregunta en una entrevista al investigador en venenos animales -especializado en venenos de reptiles- . Bryan G. Fry]:
Given your recent research on venom present in colubrids formerly thought to be harmless, should greater care be taken in the handling of Asian Elaphe?
For snakes such as the Radiated rat snake (Coelognathus radiatus) or various species of Garter snakes (Thamnophis) the full gamut of effects are almost certainly known, with only a low incidence of mild local reactions reported. Although, neurotoxic garter snake bites have been reported, consistent with the presence of 3FTx (three-finger toxins) in the venom. Where care should be taken is with species for which nothing is really known. A good example of sensible precaution is with the Jackson’s black tree snake (Thrasops jacksonii). No one has ever reported a significant bite from them but there haven’t been many opportunities since the keepers almost universally give the snakes a lot of respect due to the very quick (and bloody) prey death that occurs when they are fed live mice. With snakes which haven’t been imported before, a bit of sensible caution should be used till a few live prey feedings give a reasonble start of a feeling about toxicity or (even better) some research data is known about the potency and action of the venom. For example, we didn’t expect the Egyptian Catsnake (Telepscopus dhara) to have such massive venom glands, far bigger than many elapids. Big venom yields. 15+ milligrams from 30 cm snakes in a species that gets 1.2 meters. The venom is as toxic as a cobra. No antivenom. Very much not what we expected!
Fuente:
http://www.redtailboa.net/forums/interviews-more/27496-dr-bryan-greg-fry-interview.html
Estos son algunos enlaces a documentos relacionados:
http://vipersgarden.at/PDF_files/PDF-296.pdf
http://vipersgarden.at/PDF_files/PDF-2306.pdf
http://www.sciencedirect.com/science/article/pii/0041010185903769
http://www.sciencedirect.com/science/article/pii/S019606449470113X
http://www.llu.edu/pages/faculty/whayes/documents/1985_hayes_toxicon_human_envenomation_garter_snake.pdf
http://www3.ntu.edu.sg/eee/urop/congress2003/Proceedings/abstract/NUS_FoS/Biological%20Sciences/Sheik%20Fadil%20Ryan%20Ramjan.pdf
http://public.wsu.edu/~kkardong/Web%20of%20KVK_06b/Publications/Function_teeth_garter79.pdf