SciAm article:
June 25, 2004
<snip>
"Morphine acts on a part of the brain known as the opioid system,
which is linked to pain, pleasure and addictive behaviors. The results of a
mouse study published in today's issue of the journal Science suggest that
the same brain circuitry plays a role in mother-infant bonding.
Previous animal research had implicated the opioid system in the
forming of lasting attachments but exactly how it did this was unclear. In
the new work, Francesca R. D'Amato of the CNR Institute of Neuroscience,
Psychology and Psychopharmacology in Rome and her colleagues studied
so-called knockout mice that lacked u-opioid receptors. The team observed
newborn pups that had been separated from their mothers and found that mice
lacking the receptors made fewer distress calls when they were abandoned
than normal mice did. When the control animals were given morphine they
calmed down, but the drug had no effect on the knockout mice. The
researchers also gave the animals a choice between two cages, one they had
been exposed to before and one that was unfamiliar. Whereas the normal mice
all chose the familiar surroundings, two thirds of the knockout animals
seemed content to bed down in a strange mother's nest.
The results suggest that u-opioid receptors are "critical players in
attachment disorders," the scientists note. In addition, they lend further
support to the theory that malfunction of the opioid system could be to
blame for the social indifference seen in autistic infants. --Sarah Graham"
==================
My comment:
It also suggests (to me) that the knocked-out gene has a "macro phenotyping"
function that underlies _both_ the involved need for a mother _and_ the
u-opioidergic (or wider opioidergic?) control of a "lack of mothering type"
SHITS.
P