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From: howard@cpocd2.UUCP
Newsgroups: sci.bio
Subject: Re: Octopus....fish, reptile or what?
Message-ID: <795@cpocd2.UUCP>
Date: Mon, 20-Jul-87 13:41:22 EDT
Article-I.D.: cpocd2.795
Posted: Mon Jul 20 13:41:22 1987
Date-Received: Thu, 23-Jul-87 01:42:22 EDT
References: <596@xn.LL.MIT.EDU> <2797@phri.UUCP>
Reply-To: howard@cpocd2.UUCP (Howard A. Landman)
Organization: Intel Corp. ASIC Systems Organization, Chandler AZ
Lines: 34

In article <2797@phri.UUCP> lonetto@phri.UUCP (Michael Lonetto) writes:
>These animals also have very fast, complex nervous systems, once again
>on a par with vertebrate systems.  Interestingly, the speed is achieved
>without myelination of the nerve axons (the system used in vertebrates).
>Instead, the axons are enormous in size (hence the use of the "giant" 
>squid axon in neurotransmission studies.

Even more interesting is that octopus nervous systems use neurohormones
which are catecholamines, and are very similar to adrenaline and
noradrenaline (also catecholamines).  (Nor)Adrenaline is also called
(nor)epinephrine.  The synthetic pathways are also similar, with about
as much difference between different species of octopus as there is
between some octopi and humans.  (The enzymes involved are different,
but the sequence of transformations from phenylalanine -> tyrosine ->
... -> final hormone is nearly identical to human in some species.)
Considering that this entire pathway appears to have evolved separately
from the mammalian one, the parallel is remarkable.

This leads to some curious speculations.  For example, it is quite
possible that certain catecholamine-like psychotropic drugs (mescaline,
MDA, "Ecstasy", amphetamines, ...) would "work" in octopi in a similar
manner to the way they "work" in humans.  Of course, this would be hard
to verify experimentally, since recording the subjective experience of
an octopus is a difficult matter.  The prospect of dealing with an
octopus on a bad trip must also give one pause :-O.

If there's any interest, I could dig out my paper on neurohormone
biosynthesis, but it's of ~1970 vintage, hence not entirely up to date.

-- 
	Howard A. Landman
	...!{oliveb,...}!intelca!mipos3!cpocd2!howard
	howard%cpocd2%sc.intel.com@RELAY.CS.NET
	"... precisely the opposite of what we now know to be true."