Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: thedoc on 22/02/2016 23:50:01

Title: How does chloroform make you unconscious?
Post by: thedoc on 22/02/2016 23:50:01
Deeksha Hegde asked the Naked Scientists:
   How exactly does chloroform make you unconscious? How does a slightly larger dose cause death?
What do you think?
Title: Re: How does chloroform work to make you unconscious?
Post by: chiralSPO on 23/02/2016 02:45:16
As far as I understand it, the precise mechanism of action of small molecule anesthetics (like ethanol, chloroform, diethyl ether, triethylamine, Halothane, and even various solvents, xenon or high pressures of nitrogen) is not known. There is evidence that these molecules dissolve in the membranes and hydrophobic residues of neurons, thereby changing the activity of those neurons. GABA and NMDA pathways appear to be particularly important, but none of these molecules appears to be selective for one type of neuron over others--these are "general" anesthetics, and don't behave like targeted drugs such as opiates or benzodiazepines etc.

There have been some studies that showed that the effects of anesthetics to be essentially reversed in hyperbaric chambers (for instance http://www.ncbi.nlm.nih.gov/pubmed/2840107 and http://www.ncbi.nlm.nih.gov/pubmed/655442), but it is not exactly clear why this happens either. See also: https://en.wikipedia.org/wiki/Theories_of_general_anaesthetic_action

As to how these can lead to death--the extent to which these compounds inhibit neural activity is very much dose dependent: higher doses → less neural function. This includes the neural pathways that control breathing (and I think heart rate as well, though I could be mistaken), so too little neural activity leads to failure to breathe...