Lethal Injections

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Recently in the news, a story broke about long-time prisoner Troy Davis who was executed through lethal injection. This story caught my interest, not due to the legal aspect, but to the scientific aspect. It brought to my attention the fact that I do not understand how lethal injections work. After all, with our powerful bodies, how can one simple injection kill us?


After doing some simple research, I found out that "death by lethal injection" should actually be called "death by three lethal injections." It is important to note that each injection contains lethal amounts of powerful drugs, so as to ensure the death of the intended victim. First, an anesthetic called sodium thiopental depresses the activity of the central nervous system. As we have recently learned, without a properly functioning CNS, body functions are decreased greatly. Specifically, this drug increases the effect of GABA, a neurotransmitter that has an inhibitory effect of brain activity. 


Following a saline flush, which is used to push the drug to enter the bloodstream faster, the second drug is administered. This time, the injection consists of a high dose of pancuronium bromide. This drug acts as a neuromuscular blocker, preventing the neurotransmitter acetylcholine from communicating with muscles. This loss of function from ACh stops all muscle function and leads to paralysis. This, in turn, leads to the end of breathing because the diaphragm muscle is no longer able to contract and expand.


After another saline flush, the third injection can be administered. This is the substance we usually think of as lethal -- potassium chloride. This drug attacks the heart with charged particles that interrupt the hearts' electrical signaling. The most interesting piece of information -- the entire process usually takes less than ten minutes! It's so hard for me to believe that a person can be put to death by lethal injection in less than a quarter of an hour. 


Researchers have become interested in post-mortem reports of prisoners who have died by lethal injection because the concentrations of the three drugs used get quickly absorbed into fat and muscle tissue, even after death. Some claim that an excess concentration of drugs are necessary for injection into the bloodstream to ensure the prisoner does not survive through the process.


Each part of the lethal injection process directly relates to the nervous system we are discussing in class, thus it made my investigation very interesting. We have briefly discussed GABA, Ach and other neurotransmitters. Researching this topic, however, has helped me understand truly how quickly those neurotransmitters work.

The information above was sourced from: http://scienceline.org/2007/11/ask-sergo-deathpenalty/