Electrons. Energy levels. Brain neurons. And how a little lithium helps to make moods better.
1-Minute NomNom
Where did the “7” in the lemon-lime soda “7-Up” come from? The “7” might have come from lithium’s atomic mass (mass of one atom of an element – see atomic diagram of lithium below) because between 1929 and 1950, the drink contained lithium.
Happy hour?
This was not surprising as it had been known since the time of the Greeks that a little bit of lithium improved one’s moods. Different studies in the US and Japan since then have found that people who drank from local water supplies with higher levels of lithium had lower levels of suicide and greater longevity.
In fact, lithium is prescribed as a medication for bipolar disorder, a “manic-depressive illness… that causes unusual shifts in mood, energy, activity levels.”
Li: atomic mass/nucleon number of ~7; atomic (proton) number of 3; with 2 electrons in inner shell, and 1 electron in outer shell
Scientists are still researching how lithium works in the brain. One interesting explanation has to do with electrons. All the electrons in an atom are arranged in shells or energy levels around the nucleus. Lithium, for example, has two shells, with two electrons in the inner shell and one electron in the outer shell.
Na: atomic mass/nucleon number of ~23; atomic (proton) number of 11; with 2 electrons in inner shell, 8 in middle shell, and 1 in outer shell
Different elements will have different numbers of shells and electrons. Sodium, for example, has three shells, with two electrons in the innermost shell, eight in the middle, and one in the outermost.
It is this similarity in the outermost shells – one electron – of lithium and sodium that may be behind lithium’s efficacy for improving the mood of the brain.
Electrical signals from the left neuron being transmitted to the right neuron via chemical signals called neurotransmitters
According to RadioLab’s Elements podcast, our neurons (i.e. nerve cells) in the brain transmit electrical signals, passing them to one another via chemical signals (known as neurotransmitters). All these are carried by sodium ions.
In conditions like bipolar disorder, “defective parts” in the brain make “moods flip on and off… intensely”. The signals for these are also carried by sodium ions.
But when lithium is present, because it has an outermost shell/electron like sodium, the neurons will use the lithium ions instead (scientists don’t really know why yet). Lithium simply “works just like sodium but not as well“. As a result, those “defective parts” causing the moods to flip on and off so intensely don’t work as well, which stops the mood swings.
As the science is still not fully understood, and there are side effects, lithium is still used with caution. That, however, has not stopped websites from suggesting we should take foods naturally rich in lithium such as sugarcane (photo above), dairy products and seaweed.
It also has not stopped us from marveling at how something as simple as the number of electrons in an outer shell could help to cure disorders and save lives.
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