week 4

Neurotransmitter Systems (ch. 6)

This post is a little late, but the reason is quite understandable as the weeks topic was one of the hardest to comprehend and digest. Putting it plainly, chemistry has never been my strongest subject so the amount of effort in googling and note taking of chapters 5 (last weeks chapter, but required for this weeks understanding) & 6 took some time. It took three times of reading the chapters through to be exact. No joke!

From neurotransmitter systems to neurotransmitter chemistry the exact mechanisms that allow for pre- & postsynaptic neurons to relay messages fast through transmitted-gated channels and slower through g-protein-coupled receptors opened my eyes to the complexity and thereby the weaknesses of our neural system. I’ve always been fascinated about how our brain can ignite memories, emotions and movement coordination with such precision. To top this, it’s amazing that there are only three types of neurotransmitters that do all of it – amino acids, amine and peptides. What creates differences is where these messages are being sent (PNS or CNS), the type of presynaptic neuron sending the neurotransmitter and the postsynaptic neuron receiving. Even the thought of the multitude of different combinations and arrangements of subunits of receptors gives rise to numerous outcomes of what happens in signaling. As said in the book:

“The immense chemical complexity of synaptic transmission makes it especially susceptible to the medical corollary of Murphy’s law, which states that if a physiological process can go wrong, it will go wrong.” – chapter 6, page 131

But again it was interesting to read on all the things that could go wrong! The most interesting being about cell death and how easily it can happen. And mammalian brain cells don’t regenerate so we are stuck with what we have. Glutamate the most abundant neurotransmitter is also a neuron killer when blood flow ceases. Within a few minutes permanent damage is done. With the production of ATP stopped membranes depolarize, and Ca2+ leaks into cells causing rapid depolarization of neurons. This overexciting of neurons is called excitotoxity and is equivalent to neurons digesting themselves.

What are my thoughts on all of this? Well I came to thinking about migraines. I’ve suffered from them almost my entire life and it would be interesting to find an answer to what causes them. Its said to be a chemical imbalance in the brain involving the nerves and blood vessels, but what exactly causes them is still unknown. Could it be an underlying problem with a neurotransmitter or receptor? Or a neuro transporter issue?

I don’t have any more enlightening thoughts, but hope the following weeks readings won’t be as hard to digest 😀