Gingko Biloba stands out from other memory supplements because it appears to work via GABAergic signaling. GABA-A receptors are composed of many different subunits that come together to create a full GABA-A receptor and when we target specific GABA-A receptor subunits, such as a1 and a5, we may help promote memory! Specifically, we are talking about blocking GABAergic signaling, which may raise some red flags for some, as we often want to promote GABAergic activity in order to help promote relaxation. While it is true that blocking whole GABA-A receptors is highly undesirable in general, once we break it down into each individual subunit that makes up the GABA-A receptor, the picture becomes a little bit clearer. Allow us to demonstrate by taking a look at only the alpha subunits for simplicity sake:
GABA-A receptor subunits (alpha types)
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- a1: Activation of these subunits produce calming and muscle relaxing effects. However, this comes at the major expense of diminished memory function. Blocking this subunit on the other hand, will do the opposite, and this leads to a memory promoting effect.
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- a2: Activation of these subunits produce a calming effect with no effects on memory.
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- a3: Activation of these subunits produce a calming effect with no effects on memory.
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- a4: Activation of these subunits play a large role in the reward/pleasure pathways in our brains.
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- a5: Similar to activation of a1, activation of these subunits produce calming and muscle relaxing effects. However, this also comes at the major expense of diminished memory function. Blocking this subunit, just like with a1, will do the opposite, and this also leads to a memory promoting effect.
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- a6: Activation of these subunits produces a calming effect with minimal impact on memory at low activation levels. At high activation levels, a6 subunit activation may negatively impact explicit memory without affecting implicit memory.
As can be seen from the list above, generally blocking GABA-A receptors is obviously not a great idea, and so we have to be highly selective in how we block various GABA subunits in order to achieve a memory promoting effect without affecting relaxation, stress and mood. To accomplish this, Ginkgo Biloba needs to specifically antagonize just the GABA-A subunits that control memory without antagonizing the GABA-A subunits responsible for relaxation. Luckily, this is exactly what Ginkgo does!
Ginkgo Biloba may promote memory by antagonizing a1 subunits. As we displayed in the list of subunits and effects above, when activated, a1 units have a negative impact on memory and thus blocking a1 should have a positive effect on memory. While no direct research appears to have been done on selectively blocking a1 subunits, there have been some studies that have shown that blocking a5 subunits has significant effects on promoting memory. It has, however, been proven that a1 subunits control procedural memory. Based on this, we could make the conclusion that inhibiting a1 subunits with bilobalide may promote procedural memory function. This also raises an interesting point, that bilobalide is perhaps one of the only selective a1 subunit antagonists, which is quite an exciting prospect within the context of memory promotion!
That all being said, GABA isn’t the only way that Ginkgo Biloba promotes memory! Ginkgo Biloba also regulates norepinephrine transporters which helps promote norepinephrine and other catecholamine levels in the brain, specifically in the prefrontal cortex. Norepinephrine plays a major role in memory function, and when combined with other catecholamines in the prefrontal cortex, may also helps promote executive function!
Furthermore, Ginkgo Biloba also likely promotes memory via promoting neurogenesis. Memory is actually a real physical change in the brain and neurogenesis helps facilitate this process. Neurogenesis may be a result of the other memory effects mentioned above plus additional support to brain derived neurotrophic factor (BDNF). Overall, Ginkgo Biloba is clearly a heavy hitter when it comes to memory function so it is no surprise that it is one of the most popular natural nootropic supplements available to buy!
