送交者: Latino2 于 2005-1-06, 18:05:44:
俺"奶"故俺爽。
要是这个理论在人类也成立的话，绿的戒毒瘾就好办了。
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Motherhood is a Drug
By MARY BECKMAN
Who needs drugs when nursing can be such a great high? New research shows
that brain scans of suckling moms are indistinguishable from those of virgin
rats on cocaine, supporting the idea that nature rewards mothers for nurturing
their pups. The work, described in 5 January issue of the Journal of Neuroscience,
also sets the stage to better understand the mother-child bond in humans.
When given the choice, rats with babies under 8 days of age will choose suckling
their pups over cocaine. Researchers believe this strong motivation to nurse
has evolved to help mothers bond with their offspring. Previous work involving
damaging parts of the brain or blocking neurotransmitters has shown that
the reward system of the brain is involved both in suckling and in drug
stimulation. But no one had imaged the brain of a conscious rat for these
studies. To address this, Craig Ferris of the University of Massachusetts
Medical School in Worcester and colleagues monitored the effect of suckling
and cocaine use in wide-awake mother rats using magnetic resonance imaging
(MRI) of the entire brain. When the team compared the MRIs of suckling mother
rats to virgin rats given cocaine, it found that the same areas of the brain
lit up in both groups. If the mother rats received injections of cocaine,
the reward system in their brains dipped in activity below the lactation
high, suggesting that lactation somehow interferes with the rewarding effects
of cocaine. This work will allow scientists to bridge what we know about
rats to humans, says neuroscientist Joan Morrell at Rutgers University in
Newark, New Jersey. "And it's a good overview of the systems that get turned
on during suckling and drug use."