Nav: Home

New study examines the way estrogen affects methamphetamine addiction

February 06, 2019

Male rats have held steady as the focus of most addiction studies in the past. But as the field begins to take female rats into account, scientists see that drugs like methamphetamine affect the sexes differently, suggesting the basis for a change in addiction treatment.

"The brain changes when you've been addicted to methamphetamine," said Antonieta Lavin, an associate professor in the neuroscience department at the Medical University of South Carolina who worked on the study with fellow researcher Carmela Reichel. "But we have limited information on how our sex hormones affect that addiction."

In a paper published January 10, 2019 in eNeuro, MUSC researchers suggest that the brain of a female rat responds differently to drugs like methamphetamine and that these differences may be due to the presence of estrogen and its effect on addiction.

According to the Centers for Disease Control and Prevention, methamphetamine alone is responsible for 11,000 deaths in the United States each year, and with more than 70,000 total drug-related deaths in 2017, researchers like Lavin and Reichel are working to improve treatment for those with substance use disorder.

As a stimulant, methamphetamine increases activity in certain areas of the brain, such as the prefrontal cortex. And according to the American Addiction Centers, the drug releases dopamine in the brain, which gives the user a sense of pleasure. In addition to this rewarding feeling, dopamine also controls a person's motivation, movement, memory and learning.

By consistently releasing excess dopamine, methamphetamine users train the brain to expect and crave heightened levels of this neurotransmitter, and the same happened with the male and female rats in this study.

Researchers gave their test subjects the ability to self-administer methamphetamine, meaning that the rats were able to control how much of the drug they consumed and how often they took it. Female rats consistently took more methamphetamine more often during the first six hours of their addiction, and the researchers involved suggest that this window may be crucial in explaining why female addiction is so powerful.

Over time, methamphetamine addiction alters the way in which signals are carried throughout the brain, specifically targeting the synapses in the prefrontal cortex, where the brain controls decision-making and learning.

When MUSC researchers examined the prefrontal cortices of both male and female rats addicted and not addicted to methamphetamine, they found that the synaptic response in this area was different between males and females as well as between the addicted and non-addicted animals. For example, Lavin and Reichel found that female rats showed lower resting activity than male rats but then experienced a faster rise in their brain's synaptic activity after taking the drug. This stronger response was then followed by a faster fall once the drug wore off.

This synaptic difference between males and females suggests that sex hormones play a larger role than previously thought in how rats, and potentially humans, process drugs and could lead to more male- and female-specific substance abuse disorder treatment in the future.

"Next, I would like to study how meth addiction changes throughout the different phases of the female cycle," said Lavin. "This insight would help us improve treatment for women suffering from substance use disorder."
-end-
About MUSC

Founded in 1824 in Charleston, The Medical University of South Carolina is the oldest medical school in the South. Today, MUSC continues the tradition of excellence in education, research, and patient care. MUSC educates and trains more than 3,000 students and residents, and has nearly 13,000 employees, including approximately 1,500 faculty members. As the largest non-federal employer in Charleston, the university and its affiliates have collective annual budgets in excess of $2.2 billion. MUSC operates a 750-bed medical center, which includes a nationally recognized Children's Hospital, the Ashley River Tower (cardiovascular, digestive disease, and surgical oncology), Hollings Cancer Center (a National Cancer Institute designated center) Level I Trauma Center, and Institute of Psychiatry. For more information on academic information or clinical services, visit http://www.musc.edu. For more information on hospital patient services, visit http://www.muschealth.org.

Medical University of South Carolina

Related Dopamine Articles:

Brain scans show dopamine levels fall during migraine attacks
Using PET scans of the brain, University of Michigan researchers showed that dopamine falls and fluctuates at different times during a migraine headache.
Hard choices? Ask your brain's dopamine
Salk researchers learn how dopamine governs ongoing decisions, yielding insights into Parkinson's, drug addiction.
Alcoholism may be caused by dynamical dopamine imbalance
Researchers from the Higher School of Economics, Ecole Normale Supérieure, Paris, Indiana University and the Russian Academy of Sciences Nizhny Novgorod Institute of Applied Physics have identified potential alcoholism mechanisms, associated with altered dopaminergic neuron response to complex dynamics of prefrontal cortex neurones affecting dopamine release.
Precise technique tracks dopamine in the brain
MIT researchers have devised a way to measure dopamine in the brain much more precisely than previously possible, which should allow scientists to gain insight into dopamine's roles in learning, memory, and emotion.
Neurotrophic factor GDNF is an important regulator of dopamine neurons in the brain
New research results are expanding our understanding of the physiological role of the glial cell line-derived neurotrophic factor GDNF in the function of the brain's dopamine systems.
Sensory stimuli control dopamine in the brain
In their study of fish larvae, Prof. Dr. Wolfgang Driever and his team of neurobiologists at the University of Freiburg discovered that a group of nerve cells in the forebrain release the neurotransmitter dopamine when activated by tactile or certain visual stimuli.
Sensory stimuli control dopamine in the brain
Type and intensity of stimuli control the activity of nerve cells that release the neurotransmitter dopamine.
The emergence of a new dopamine hypothesis of schizophrenia
Biological Psychiatry presents a special issue, 'The Dopamine Hypothesis of Schizophrenia,' dedicated to recent advances in understanding the role of dopamine signaling in schizophrenia.
Breakthrough in the production of dopamine neurons for Parkinson's disease
Researchers at Lund University, Sweden, are rapidly moving towards the first ever transplantations of embryonic stem cell derived dopamine neurons in persons with Parkinson's disease.
Activating dopamine neurons could turn off binge-like eating behavior
While binge eating affects about 10 percent of adults in the United States, the neurobiological basis of the disease is unclear.

Related Dopamine Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...