FOR IMMEDIATE RELEASE
Contact:
Donna Krupa
703.527.7357 (direct
dial)
703.967.2751 (cell) or
djkrupa1@aol.com
ESTROGEN MAY PROTECT AGAINST COCAINE-INDUCED BRAIN
DYSFUNCTION
Estrogen appears to counteract
the addictive drug’s restriction of blood flow to the brain. These findings
may also lead to treatments for age-associated blood flow abnormalities
PITTSBURGH, Pa. -- The Office of National Drug
Control Policy estimates that the number of chronic cocaine users in the
United States stands at 3.6 million. The National Institute on Drug Abuse
asserts that men are more prone to use and addiction; now, a team of
researchers believe that women users have an added edge – their
physiological profile may shield them from cocaine’s brain altering effects.
Additionally, this research may lead to a new therapy that may help cocaine
users “kick the habit,” a difficult challenge under any circumstance.
Researchers have known that women are less inclined to
be a victim of vascular disorders caused by chronic use of the drug. What
the scientific community did not know was why. Now, a team of medical
researchers affiliated with Harvard University Medical School has found that
during the first half of a women’s menstrual cycle, the susceptibility to
vascular dysfunction may be lower than the corresponding propensity for male
users. Only in the latter stages of the menstrual cycle did women
experience a significant degree of vasoconstriction (restriction of blood
flow to the brain).
“Cocaine-Induced Cerebral Vasoconstriction Differs as a
Function of Sex and Menstrual Cycle Phase” is the subject of a study
recently conducted by Marc J. Kaufman, Jonathan M. Levin, Luis C. Maas,
Thellea J. Kukes, Rosemond A. Villafuerte, Kerstin Dostal, Scott E. Lukas,
Jack H. Mendelson, Bruce M. Cohen and Perry F. Renshaw. Their findings,
published in the May 1, 2001 edition of Biological Psychiatry, are
being presented at the upcoming conference, Genomes and Hormones: An
Integrative Approach to Gender Differences in Physiology, sponsored by
the American Physiological Society (APS) October 17-20, 2001, at the Westin
Convention Center, Pittsburgh, Pa.
Methodology
Lead researcher Marc Kaufman and his colleagues first
established the rate of blood flow to the brain in male and female
occasional cocaine users. An intravenous dose of cocaine (0.4 mg/kg) was
administered to nine men and 13 women. Men were studied once while women
were examined during different phases of their menstrual cycle phases (days
3-8, follicular phase and 18-24, leutial phase) after the beginning of
menstruation.
Reduction in blood flow to the brain was measured with
Dynamic Susceptibility Contrast functional magnetic resonance imaging (MRI),
which uses a magnetic resonance contrast agent to detect changes in blood
flow.
Results
In the follicular phase, when estrogen levels are high
and progesterone levels are low, cocaine did not alter the amount of blood
in the brain. By contrast, a 10 percent reduction in blood was found in
women during their luteal menstrual cycle phase, when progesterone levels
rise; male subjects incurred a 20 percent loss. These findings suggest that
cocaine’s effects on blood vessels in the brain differ as a function of sex
and menstrual cycle phase, and imply that progesterone in women and
testosterone in men may enhance cocaine-induced vasoconstriction, while
estrogen in women may blunt cocaine’s vascular effects.
Significance of Findings
Previous studies have asserted that chronic cocaine
users are found to be more prone to strokes than non-abusers of the drug.
Abusers have also been found to suffer damage to electrical activity of the
brain, which may be secondary to reduced blood flow.
Estrogen, or a synthetic estrogen-like compound, could
be helpful in treating the two percent of Americans needing relief from
cocaine addiction, by reducing damage caused to the brain by the addictive
drug. Such benefits could extend beyond drug using populations. For
example, treatments that improve brain blood flow might also benefit the
elderly, many of whom experience reductions of blood flow to the brain as a
result of aging.
-end-
The
American Physiological Society (APS) was founded in 1887 to foster basic and
applied science, much of it relating to human health. The Bethesda,
MD-based Society has more than 10,000 members and publishes 3,800 articles
in its 14 peer-reviewed journals every year.
***
Editor’s Note: To receive a copy of the abstracts, to interview speakers or
for more information, contact Donna Krupa at 703.527.7357(direct dial),
703.967.2751 (cell) or djkrupa1@aol.com.
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