University of California, San Diego
The Department of Psychology is Honored
to Present a Talk by
Ruth Wood
University of Southern California
"ANABOLIC STEROID ADDICTION?
INSIGHTS FROM ANIMAL STUDIES"
Presented on April 21, 2005
Location: The Crick Conference Room
Mandler Hall, room 3545
- Abstract:
- Androgenic-anabolic steroids (AAS) are drugs of abuse. They are taken in
large quantities by athletes and others to increase performance, with
negative long-term health consequences. Although AAS were banned from
Olympic competition in 1975, steroid abuse continues. However, the
potential for reinforcement and addiction to AAS has received relatively
little attention. In particular, it is difficult in humans to separate
the direct psychoactive effects of AAS from reinforcement due to their
systemic anabolic effects. Recent studies in rats and hamsters have
demonstrated that testosterone is reinforcing using conditioned place
preference and self-administration. In particular, our laboratory has
provided evidence of voluntary testosterone intake, including oral,
intravenous, and intracerebroventricular (icv) self-administration. Male
Syrian hamsters self-administer testosterone, dihydrotestosterone,
nandrolone decanoate, or drostanolone icv across a range of concentrations
(0.1-2.0 ug/ul). Moreover, the antiandrogen flutamide blocks testosterone
self-administration. Circulating androgens appear to enhance sensitivity
to self-administration of exogenous androgens because operant responding
for testosterone at 0.1 ug/ul is reduced in females and castrated males.
When taken in large doses (>40 ug in 4h), testosterone icv produces torpor
and, occasionally, death. Symptoms of androgen overdose resemble those of
opioid intoxication, and androgen withdrawal can be induced by the opioid
antagonists naloxone and naltrexone. However, with continued exposure,
hamsters develop tolerance to the depressive effects of testosterone.
Tolerance and withdrawal are key criteria for addiction. Thus, it appears
that AAS may be addictive, even in an experimental context where athletic
performance is irrelevant.
- About the Speaker:
- Research in my laboratory investigates how gonadal steroids, particularly androgens, influence brain function. Our model is the Syrian hamster. Currently, we are pursuing two questions. First, we are trying to understand how hormonal information from the internal environment is combined with external sensory stimuli to regulate behavior. Current understanding of sensory systems has come largely from studies presenting individual sensory cues to experimental subjects. However, the world is not perceived as a series of isolated sensory events. In our model, male hamsters integrate odor cues from females with testosterone from the gonads to control expression of sexual behavior. We are trying to understand where and how such sensory and hormonal integration takes place. A second research question concerns reward and possible addiction with anabolic steroid abuse. Although anabolic steroids were classified as controlled substances in 1991, their addiction potential remains unknown. We have recently shown that hamsters will self-administer testosterone, including self-administration directly into the brain. This suggests that anabolic steroids are rewarding, independent of their anabolic effects.
For More Information About This Speaker:
- http://www.usc.edu/programs/pibbs/site/faculty/wood_r.htm
Dr. Wood's webpage.
