Researchers identify possible new targets for treating pain in women
Women and men experience pain, particularly chronic pain, very differently. The ability of some opioids to relieve pain also differs between women and men. While it has been recognized since the mid-nineties that some narcotic analgesics are more effective in women than men, the reason for this difference was largely unknown.
Narcotic analgesics decrease pain by activating opioid receptors, which are located on nerves that transmit painful sensations. Since levels of mu, delta, and kappa opiate receptorsthe three main types of opioid receptor in the brain and spinal cordare not thought to differ dramatically in men and women, it was difficult to understand why the effectiveness of some painkillers is dependent on sex.
Now, research supported by the National Institute of Drug Abuse (NIDA) has revealed that the same major types of opioid receptor interact differently, depending on sex. The spinal cord of female laboratory animals was found to contain almost five times more kappa-mu heterodimera complex of mu-opioid and kappa-opioid receptorthan the spinal cord of male animals. Furthermore, the amount of mu-kappa heterodimer in the spinal cord of the females was about four times higher when their levels of estrogen and progesterone were at their peak. Subsequently, researchers found that both estrogen and progesterone are critical for the formation of mu-kappa opioid receptor heterodimers.
This research was conducted by Alan Gintzler, PhD, professor of biochemistry, Department of Obstetrics and Gynecology, and his senior collaborators Sumita Chakrabarti, PhD, and Nai-Jiang Liu, PhD, at the State University of New York (SUNY) Downstate Medical Center
The discovery of a mu-kappa opioid receptor complex that is more prevalent in the spinal cord of females than males and that is synchronized with the ebb and flow of ovarian hormones could explain why drugs used to treat pain, such as pentazocine, nalbuphine, and butorphanolwhich primarily act on mu-opioid and kappa-opioid receptorsare more effective in women than men. The activation of the kappa-opioid receptor within the kappa-mu-opioid receptor complex could provide a mechanism for recruiting the pain-relieving functions of spinal kappa-opioid receptors without also activating their pain-promoting functions.
The research by Drs. Gintzler, Liu, and Chakrabarti, which was recently published in the Proceedings of the National Academy of Sciences and the Journal of Neuroscience, suggests that kappa-mu opioid receptor heterodimers could function as a molecular switch that shifts the action of kappa-opioid receptors and endogenous chemicals that act on them from pain-promoting to pain-alleviating. Kappa-mu opioid receptor heterodimers could serve as a novel molecular target for pain management in women.
Dr. Gintzler's research suggests that physicians should take the stage of the menstrual cycle into account before deciding which drugs to prescribe to treat pain in women. While some drugs might be very effective in treating pain at times when estrogen and progesterone levels are high, they could heighten pain when levels are low. "This consideration could become even more critical in managing pain in postmenopausal and elderly women," said Dr. Gintzler. "Further research is needed to flesh out these possibilities."
The Journal of Neuroscience paper appeared in the August 17, 2011 edition.
Provided by SUNY Downstate Medical Center
- Study first to pinpoint why analgesic drugs may be less potent in females than in males Dec 23, 2008 | not rated yet | 0
- Study first to pinpoint why analgesic drugs may be less potent in females than in males Jan 05, 2009 | not rated yet | 0
- Why don't painkillers work for people with fibromyalgia? Sep 27, 2007 | not rated yet | 0
- Researchers find new target to improve pain management Sep 07, 2010 | not rated yet | 0
- Opioids and cannabinoids influence mobility of spermatozoids Jun 20, 2008 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Why is zone 1 in liver more prone to ischemic injury?
21 hours ago Hi, Is it because around central vein, there is only deoxygenated blood from the vein where as in the periphery there is hepatic artery. Also why...
How can there be villous adenoma in colon, if there are no villi there
May 22, 2013 As title suggest. Thanks :smile:
How can there be a term called "intestinal metaplasia" of stomach
May 21, 2013 Hello everyone, Ok Stomach's normal epithelium is simple columnar, now in intestinal type of adenocarcinoma of stomach it undergoes "intestinal...
Pressure-volume curve: Elastic Recoil Pressure don't make sense
May 18, 2013 From pressure-volume curve of the lung and chest wall (attached photo), I don't understand why would the elastic recoil pressure of the lung is...
If you became brain-dead, would you want them to pull the plug?
May 17, 2013 I'd want the rest of me to stay alive. Sure it's a lousy way to live but it beats being all-the-way dead. Maybe if I make it 20 years they'll...
MRI bill question
May 15, 2013 Dear PFers, The hospital gave us a $12k bill for one MRI (head with contrast). The people I talked to at the hospital tell me that they do not...
- More from Physics Forums - Medical Sciences
More news stories
(Medical Xpress)—Regulating the distribution of power in neurons is done by a system that makes the national electric grid look simple by comparison. Each neuron has several thousand mitochondria confined ...
Neuroscience 8 hours ago | 4.8 / 5 (5) | 0 |
(Medical Xpress)—The human brain is able to identify individuals' voices by comparing them against an internal 'average voice' prototype, according to neuroscientists.
Neuroscience 12 hours ago | 1 / 5 (1) | 0 |
A new study determined that children and adolescents with seizures involving the temporal lobe are likely to have clinically significant behavioral problems and psychiatric illness, especially depression. Findings published ...
Neuroscience 12 hours ago | not rated yet | 0
As the human body fine-tunes its neurological wiring, nerve cells often must fix a faulty connection by amputating an axon—the "business end" of the neuron that sends electrical impulses to tissues or other ...
Neuroscience 14 hours ago | 5 / 5 (2) | 0 |
A study by researchers at Henry Ford Hospital found "substantial evidence" that a regenerative process involving damaged nerve fibers in the spinal cord could hold the key to better functional recovery by most stroke victims.
Neuroscience 14 hours ago | not rated yet | 0 |
A brief visual task can predict IQ, according to a new study. This surprisingly simple exercise measures the brain's unconscious ability to filter out visual movement. The study shows that individuals whose ...
13 hours ago | 4.4 / 5 (9) | 0 |
Teams of highly respected Alzheimer's researchers failed to replicate what appeared to be breakthrough results for the treatment of this brain disease when they were published last year in the journal Science.
11 hours ago | 5 / 5 (1) | 2 |
Scientists at the National Institutes of Health report they have discovered in mouse studies that a small molecule released in the spinal cord triggers a process that is later experienced in the brain as ...
11 hours ago | 5 / 5 (2) | 0 |
Little is known about why asthma develops, how it constricts the airway or why response to treatments varies between patients. Now, a team of researchers at Weill Cornell Medical College, Columbia University Medical Center ...
12 hours ago | not rated yet | 0 |
High blood glucose is associated with poor outcomes in hospitalized patients, and use of intensive insulin therapy (IIT) to control hyperglycemia is a common practice in hospitals. But the recent evidence does not show a ...
1 hour ago | not rated yet | 0
Ethnic background plays a surprisingly large role in how diabetes develops on a cellular level, according to two new studies led by researchers at the Stanford University School of Medicine.
9 hours ago | not rated yet | 0 |