How do anaesthetics target a specific area of the brain?



This really applies to all drugs but I’m curious as to how getting anaesthetics injected into your bloodstream can flow through your entire body and find the exact place in your brain that it needs to target. I believe the ones that are strong enough to put you to sleep target the amygdala as well as some other areas (I could be wrong) but how is it that only those areas of the brain area affected?

In: Biology

Different brain nerves have different shaped holes that only specific shaped stuff can get inside. We put stuff with this specific shape in your body OR close enough shape OR something that is shaped like it but that blocks the hole making it stop working.

Long story short: we don’t. Most commonly, the way we make sure it hits the area we want it to hit is to send it *everywhere*. This can often result in effects we don’t necessarily want. Basically, side effects. If you have a headache and you take ibuprofen, it doesn’t just target the COX enzymes in your head; it targets COX enzymes throughout the body. In some relatively rare cases, this can temporarily (or permanently) shut down your kidneys.

Anesthetics injected into the blood stream go everywhere in the body. We just have to ensure that there is enough of it at the site of action to have the desired effect.