Octopamine

Octopamine
Systematic (IUPAC) name
4-(2-amino-1-hydroxy-ethyl)phenol
Identifiers
CAS number	104-14-3
ATC code	C01CA18
PubChem	4581
Chemical data
Formula	C8H11NO2
Mol. mass	153.178
Synonyms	Norsympatol, Norsynephrine
Pharmacokinetic data
Bioavailability	?
Metabolism	?
Half life	< 15 Minutes in insects. Theorized to be longer in animals.
Excretion	?
Therapeutic considerations
Pregnancy cat.	?
Legal status
Routes	?
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Octopamine is a biogenic amine that is closely related to noradrenaline, and has noradrenergic and dopaminergic effects.^[1] Biosynthesis of the D(-) enantiomer is by β-hydroxylation of tyramine by the enzyme dopamine β-hydroxylase. Synthetic octopamine can be prepared by laboratory synthesis.^[2] Other common names for octopamine include: para-hydroxy-phenyl-ethanolamine, benzemethanol, norsympathol, norsynephrine, para-octopamine, beta-hydroxy-tyramine and others.

Role in invertebrates

Octopamine was first discovered by Italian scientist Vittorio Erspamer in 1948^[3] in the salivary glands of the octopus and has since been found to act as neurotransmitter, neurohormone and neuromodulator in invertebrates. It is widely used in energy-demanding behaviours by all insects, crustaceans (crabs, lobsters, crayfish), and spiders. Such behaviours include flying, egg-laying, and jumping.

The best-understood role for octopamine is in the locust jump. Here it modulates muscle activity, making the leg muscles contract more effectively. This is at least in part due to an increase in the rate of contraction and of relaxation.

In the honey bee and fruit fly, octopamine has a major role in learning and memory. In the firefly, octopamine release leads to light production in the lantern.

Octopamine also plays a role in mollusks, though the role of octopamine has been examined only in the central nervous system of the model organism, the pond snail.

Heberlein et al. ^[4] have conducted studies of alcohol tolerance in fruit flies; they found that a mutation that caused octopamine deficiency also caused lower alcohol tolerance.^[5][6][7][8]

The emerald cockroach wasp stings the host for its larvae (a cockroach) in the head ganglion (brain). The venom blocks octopamine receptors^[9] and the cockroach fails to show normal escape responses, grooming itself excessively. It becomes docile and the wasp leads it to the wasp's den by pulling its antenna like a leash. ^[10]

Role in vertebrates

In vertebrates, octopamine also replaces norepinephrine in sympathetic neurons with chronic use of monoamine oxidase inhibitors. It is responsible for the common side-effect profile of orthostatic hypotension with these agents.

In mammals, octopamine may mobilize the release of fat from adipocytes (fat cells), which has led to its promotion on the internet as a slimming aid. However, the released fat is likely to be promptly taken up into other cells, and there is no evidence that octopamine facilitates weight loss. Octopamine may also increase blood pressure significantly when combined with other stimulants, as in some weight loss supplements. ^{[11] [12]}

Due to lack of research, much is not known about octopamine or its role in humans.

See also

• Phenethylamine
• Tyramine

References

Further reading

• P.D. Evans, "Octopamine", in Comprehensive Insect Physiology, 11, 499, Oxford University Press 1985.