Dave STOP plagiarizing Kandel Schwartz and Jessell
They require sugar
Do I get the Nobel?That is really interesting. do you know where you found this information?
https://www.google.com/amp/s/www.sc...inkillers-could-come-from-tarantula-venom/amp
pubmed.ncbi.nlm.nih.gov
@viper69, being a highly knowledgeable reptile with a strong science background, is referring to a famous textbook:Dave STOP plagiarizing Kandel Schwartz and Jessell
I'll call up my buddy Eric Kandel to see if he'll share his with you. You deserve it.They require sugar
One of them is very good friends with a family member of mine, but never had the chance to run into them myself. A friend of mine was a postdoc in one of their labs. His paper is one that we all learn and read about in class.I’ve been thinking more and wanted to do some very crude, back-of-the-envelope type of calculations.
I remembered an oldish (2004) tarantula venom lethality testing study in which the researchers injected mice ICV with 0.1 ul of tarantula venom from 55 different species, and then timed how long it would take the mice to die.
Tarantulas: eight-legged pharmacists and combinatorial chemists - PubMed
Tarantula venoms represent a cornucopia of novel ligands for a variety of cell receptors and ion channels. The diversity of peptide toxin pharmacology has been barely explored as indicated by pharmacological, toxicological and mass spectrometry investigations on more than 55 tarantula venoms...
The paper is paywalled by the particularly wonderful-yet-[properly/legally]-eager-to-take-your-money Dutch people at Elsevier, so I will summarize for those that don’t have access.
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Results summary:
* All of the tested Asian and African species’ venoms killed the mice, most in less than 10 min, P. muticus (published under the old name C. crawshayi), S. calceatum, and P. regalis being the fastest of those tested at around 3 min, the only Cyriopagopus species (supposedly paganus) being pretty fast at about 8 min.
* 70% of the North and Central American species’ venoms did not kill the mice out to 2 hours, and of those that did the average time to death was about 25-30 min, the most lethal being [surprisingly] Avic. juruensis (published under the old name urticans) and Tap. laticeps (Note: I disagree with the authors classifying these two species as Central American -- they are South American – but let’s not complain when we’re being given data).
* 30% of the [all correctly classified as] South American species’ venoms didn’t kill the mice. Of those that did, the average time to death was about 12-15 min, with Grammostolas and Theraphosa being most deadly.
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I wish the injections weren’t done ICV (intracerebroventricular – into the middle of the brain). No tarantula can bite through your skull, and no tarantula has fangs 3+ inches long, which would be necessary to reach the cerebral ventricles. Ask an expert like @viper69, but I don’t think even Gaboon viper fangs grow so big.
SC (subcutaneous – under the skin) or IM (intramuscular – well… the meaning is obvious) injections would better simulate a tarantula bite. The ICV injections will have unrealistically concentrated the venom in the central nervous system, but this is the data we have.
So the mice injected weighed 20 g each, and an average adult human might weigh 70 kg (154 lbs), which is 3500x the weight of a mouse. What volume of venom will a biting tarantula inject? I don’t know, but unless it’s a dry bite, it will be a lot more than 0.1 ul. I’m curious if anyone knows or can make a good educated guess. Obviously, it will vary tremendously depending on the size of the spider, and whether it’s a quick bite, or really latching on and draining its venom glands. For now, let’s say 150 ul (which is about as much as 3 drops from an eyedropper, my uneducated guess for a medium duration bite from a big adult) or 1500x the volume of venom that the mice were given.
Then, by weight, the human will be dosed under the skin at only 1500/3500 = 42.86% of what the mice got straight in the brain. The above study also didn’t determine the minimum lethal doses (e.g. what if 0.05 ul of OW venom would still kill the mice and just take longer to do so). Then there’s the somewhat significant fact that we are not mice. Rodents are likely to be predators and sometimes prey. The venom is likely to be a bit more potent towards them than to us. I guess lemurs, tarsiers, monkeys, and apes are predators more like we are, more like some of us than others!
SO, there are so many uncertainties and assumptions and caveats and confounding factors, that we can’t have much confidence in drawing conclusions, but I think it would be very difficult for any tarantula to kill a healthy human adult. But even if a bite can’t kill you, it probably won’t feel good.
@viper69, being a highly knowledgeable reptile with a strong science background, is referring to a famous textbook:
Principles of Neural Science by Kandel, Schwartz, and Jessell. It's excellent and written in a very accessible way so that you don't have to be a scientist to understand it; highly recommended to anyone interested in Neuroscience.
At least about being influenced by above text:
@viper69, you caught me! I'm guilty! And you're more right than you know, because those guys all worked at my university.
James Schwartz was trained by Eric Kandel and became a famous scientist in his own right. He died just after I started grad school, and I never met him.
Thomas Jessell I met only once, but he had been the postdoc mentor of a young associate professor that helped and mentored me a great deal, so I feel a connection.
Prof. Jessell got kicked out of the university for some gross improprieties involving female subordinates. He was dying of an unspecified brain disease that may have affected his personality and judgement, so it might not be completely his fault. He was a great scientist; he died a couple of years ago.
Then, Eric Kandel, Nobel Prize winner for advancements in understanding learning and memory. He played with Aplysia (sea slugs). I met with him multiple times. I always wanted to poke him and demand, "Say something smart!" I always wanted to straighten his bow-tie; he was [or is, because he's still alive] famous for wearing colorful [and slightly crooked] bow-ties, among other better reasons for his fame. I never did poke him, because one must treat such a respectable person with respect. He has a very humble personality and was a great listener. He just listened to me and asked questions, because he wants to understand everything. I was sitting next to him at a lecture once, when he interrupted the speaker and said, "Now, I'm sorry to interrupt you, but could you just say that again please? I'm sorry, I'm an old man, and I'm a little slow, but I just want to make sure I understand you." <-- and that captures his personality perfectly. He just cares about science and wants to understand everything, in the most humble and respectful way.
I'll call up my buddy Eric Kandel to see if he'll share his with you. You deserve it.
Truly, everyone, the serpent from the tree of knowledge of good and evil had not finished his work with enlightening Eve.
He slithers among us still and enlightens us all!
I will try to remember thisDon't get bitten in your brain by a P. muticus, S. cal or P. regalis