<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
LOVE: BIOCHEMICAL ASPECTS
<br>There's no doubt in my mind that there are a whole series of biochemical
pathways that are triggered when two people meet and are attracted to each
other," says James Weinrich, Adjunct Professor of Psychiatry at the University
of California, San Diego. "One of those
<br>pathways would have to do with the experience of being 'head-over-heels'
preoccupied with someone. Where you can't get that person out of your head,
they intrude into your thoughts, and everything that they do is remarkably
charming to you."
<br>As anyone who has ever experienced it knows, the rush of falling "head-over-heels"
in love is intoxicating. And it appears to be due, in part, to the effects
of a neurotransmitter released by a region of the brain called the hypothalamus.
That neurotransmitter, called "the molecule of love" by Theresa Crenshaw,
M.D., author of The Alchemy of Love and Lust, is phenylethylamine (PEA).
<br>It causes that euphoria of falling in love. It gives that wonderful
feeling, that feeling that this person that you're attracted to can do
no harm, this person has nothing wrong with them.
<br>When PEA is high is when 'love is blind," explains Robert Friar of
Ferris State University in Michigan. It's kind of a chemical Cupid, firing
an arrow into the brain and firing up those feelings of falling in love.
<br>However, PEA doesn't act alone. When you meet someone that you're attracted
to, PEA works in conjunction with a whole slew of neurotransmitters floating
around in that love-addled brain of yours, including dopamine, norepinephrine
and serotonin. Dopamine may be involved in the "attention-getting" phase
of attraction, signaling the brain that a potential reward, in this case
a love interest, is nearby and helping focus your attention on that person.
Norepinephrine gets your blood racing and primes you for action (or to
flee, in some cases--it's involved in the so-called "fight or flight" response),
while serotonin is
<br>closely associated with the control of moods, which everyone knows
can fluctuate drastically in the process of falling in love.
<p>"It's very complex," says Friar. "When you're discussing the neurotransmitters,
it's like listening to an orchestra," he explains. "Unless all the instruments
play together in the proper rhythm and the proper sequence, you won't get
the proper effect." All the neurotransmitters are working together to create
a complex behavior that can be compared to a symphony.
<p>In this case, a symphony of attraction and love, and that symphony can
come to a final note. As most people have, at one time or another, experienced
the thrill of falling in love, so have they experienced the fading of that
initial excitement, a leveling off of the intense feelings of
<br>attraction, and possibly, a falling out of love.
<p>What brings about the change from those original feelings? It seems
that the effects of PEA have a time limit. "Typically PEA is released for
three to five years," says Friar, and he's being optimistic. Other researchers
put the end of PEA's influence at 18 months to three years.
<p>That may be the reason so many relationships tend to end in that time
period. Once the initial thrill wears off, couples may drift apart. But
obviously many stay together beyond this point in time. Some evidence suggests
the reason is that a second biochemical pathway kicks in and helps the
couple develop a longer-lasting relationship. This second pathway is involved
in bonding and forming long term attachments and may be under the influence
of at least two hormones, oxytocin and vasopressin.
<p>The Hormones of Love
<p>Testosterone is known to be important in regulating sexual desire in
both men and women. It's the hormone that helps create the desire to get
out there and get that exciting neurotransmitter symphony going, but "there's
been a big bias in favor of the so-called sex hormones, like testosterone
and estrogen, to try to explain just about everything having to do with
human sexuality," says James Weinrich.
<p>There appear to be other hormones involved in sexual behavior, specifically
in creating the next (perhaps slower) movement of the symphony, when committed
couples "settle down" for a life together. One of the hormones, oxytocin,
has been long known to be involved in childbirth and breast feeding in
<p>Recent research in animals has shown that oxytocin plays a role in the
bonding of mating pairs of prairie voles, a type of monogamous rodent.
If a female prairie vole is given oxytocin and shown a male prairie vole,
she will then pick out and bond with that specific male when later placed
in cage containing many males.
<p>Early studies in humans have suggested that women that produce higher
levels of oxytocin during pleasant experiences, like massage or remembering
a positive relationship, tended to have higher "well-being" in relationships.
<p>Both men and women release oxytocin at the moment of sexual orgasm,
suggesting that it might be involved in strengthening the bond between
couples. Another hormone, vasopressin, which is also known as anti-diuretic
hormone, or ADH, and plays and important role in kidney function, has been
shown to have an effect on male prairie voles similar to the effect oxytocin
had on females.
<p>"It's not surprising to discover that there's more than a sex steroid
pathway that's going on to influence the things that we humans associate
with sexuality, namely bonding and love," says Weinrich.
<br>As Robert Friar points out, there's still much to be learned about
the neurochemical basis of love and attraction. Much of the research has
been conducted in animals, and it's impossible to do the same experiments
with human subjects, so results have to be extrapolated. And animal experiments
are limited in the sense that, while you can measure levels of neurotransmitters
and hormones, you can't, in Friar's words, "ask a rat how it feels."
<p>Some die-hard romantics might be appalled at the idea that love can
be explained in terms of biochemistry, but an underlying chemical explanation
doesn't make the feeling of love any less real or intense. If one still
needs some amount of mystery in relation to love, perhaps it
<br>lies in the question of how a complex system of chemical reactions
can lead to the feelings and behaviors we associated with any type of emotion,
including love. As James Weinrich says, "Give Mother Nature credit for
being able to put together some pretty sophisticated and
<p>complicated mechanisms." Mechanisms that scientists will be unraveling
for many years to come.
<p>Crenshaw, Theresa L. The Alchemy of Love and Lust : How Our Sex Hormones
Influence Our Relationships. Pocket Books; 1997.
<p>Insel TR, Winslow JT, Wang Z, Young LJ. Oxytocin, vasopressin, and the
neuroendocrine basis of pair bond formation. Advances in Experimental Medicine
and Biology 1998;449:215-24.
<p>Turner RA, Altemus M, Enos T, Cooper B, McGuinness T. Preliminary research
on plasma oxytocin in normal cycling women: investigating emotion and interpersonal
distress. Psychiatry 1999;62(2):97-113 .
<p><b>Dr. Naseem Ahmed</b>