<p>The first image is the structural formula of <a href="http://en.wikipedia.org/wiki/Epinephrine" rel="nofollow noreferrer"><strong>epinephrine</strong></a> (or <strong>adrenaline</strong>, depending on where you live). </p>

<p><img src="https://i.sstatic.net/Vk9kP.png" alt="structural formula of epinephrine"></p>

<p>Epinephrine is a neurotransmitter that plays a significant role in the fight-or-flight response, and so its appearance here makes sense - Koyomi is certainly about to take flight upon seeing the "darkness".</p>

<hr>

<p>The second image contains the following compounds:</p>

<ol>
<li><a href="http://en.wikipedia.org/wiki/Dopamine" rel="nofollow noreferrer">dopamine</a></li>
<li><a href="http://en.wikipedia.org/wiki/Serotonin" rel="nofollow noreferrer">serotonin</a></li>
<li><a href="http://en.wikipedia.org/wiki/Alpha-Neoendorphin" rel="nofollow noreferrer">α-Neoendorphin</a></li>
<li>epinephrine (again)</li>
<li><a href="http://en.wikipedia.org/wiki/Enkephalin" rel="nofollow noreferrer">(Leu-)enkephalin</a></li>
<li><a href="http://en.wikipedia.org/wiki/Norepinephrine" rel="nofollow noreferrer">norepinephrine</a> (or noradrenaline)</li>
</ol>

<p>All of these are neurotransmitters, as well, though none of them are as localized to the fight-or-flight response as epinephrine is.</p>

CC BY-SA 3.0
2013-10-28T02:19:42.003Z
2013-10-28T02:50:13.067Z
2013-10-28T02:50:13.067Z
senshin
<p>In episode <strong>17</strong> of <strong>Monogatari Second Season</strong> (the first episode of <strong>Onimonogatari</strong>), when Koyomi and Mayoi see the strange "darkness", an image of the structure of a chemical compound is displayed, repeatedly:</p>

<p><img src="https://i.sstatic.net/zCAjxl.png" alt="a structural formula"></p>

<p>Shortly afterwards, a number of different chemical compounds are displayed (numbers not present in original):</p>

<p><img src="https://i.sstatic.net/1jjII.png" alt="lots of structural formulae (numbering added)"></p>

<p>What are these compounds?</p>

<monogatari-series>
What chemical compound is shown in episode 17 of Monogatari Second Season?
# What chemical compound is shown in episode 17 of Monogatari Second Season?
Posted by: username_0 on 2013-10-28
In episode **17** of **Monogatari Second Season** (the first episode of **Onimonogatari**), when Koyomi and Mayoi see the strange "darkness", an image of the structure of a chemical compound is displayed, repeatedly:

![a structural formula](https://i.sstatic.net/zCAjxl.png)

Shortly afterwards, a number of different chemical compounds are displayed (numbers not present in original):

![lots of structural formulae (numbering added)](https://i.sstatic.net/1jjII.png)

What are these compounds?
**Tags:** monogatari-series
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## 1 answers
### Answer by username_0 on 2013-10-28. Score: 13
The first image is the structural formula of [**epinephrine**](http://en.wikipedia.org/wiki/Epinephrine) (or **adrenaline**, depending on where you live).

![structural formula of epinephrine](https://i.sstatic.net/Vk9kP.png)

Epinephrine is a neurotransmitter that plays a significant role in the fight-or-flight response, and so its appearance here makes sense - Koyomi is certainly about to take flight upon seeing the "darkness".

---

The second image contains the following compounds:

1. [dopamine](http://en.wikipedia.org/wiki/Dopamine)
2. [serotonin](http://en.wikipedia.org/wiki/Serotonin)
3. [α-Neoendorphin](http://en.wikipedia.org/wiki/Alpha-Neoendorphin)
4. epinephrine (again)
5. [(Leu-)enkephalin](http://en.wikipedia.org/wiki/Enkephalin)
6. [norepinephrine](http://en.wikipedia.org/wiki/Norepinephrine) (or noradrenaline)

All of these are neurotransmitters, as well, though none of them are as localized to the fight-or-flight response as epinephrine is.
---
