Brother morphine. Research with rats may explain why opioid painkillers work better for males.
Credit: Scott Camazine/Photo Researchers Inc.
Posted on 12/31/2008 5:37:36 PM PST by neverdem
Brother morphine. Research with rats may explain why opioid painkillers work better for males.
Credit: Scott Camazine/Photo Researchers Inc.
Men get more relief than women do from painkillers like morphine, according to some studies. New research with rats hints at a possible explanation: Male rats have more receptors for the drug in a brain region involved in pain processing. Although it's not yet clear whether the same is true in humans, researchers say the study underscores the need for more research on the sex-specific effects of pain drugs.
The new study used rats in part because they exhibit a clear sex difference in morphine sensitivity, explains lead researcher Anne Murphy, a neuroscientist at Georgia State University in Atlanta. In a standard lab test, for example, both male and female rats will withdraw a paw from a hot probe in 8 or 9 seconds. After a shot of morphine, the females might tolerate the probe for another second or two, but males let the paw linger up to 20 seconds, Murphy says.
In tomorrow's Journal of Neuroscience, Murphy and colleagues report that male rats have a higher density of μ-opioid receptors in a portion of the periaqueductal gray, a brain region implicated in previous experiments as a likely site of action for opioid drugs like morphine. Injecting morphine directly into this area had a powerful analgesic effect for male, but not female, rats. When the researchers killed neurons with μ-opioid receptors by injecting a toxin bound to a morphine lookalike compound, the drug lost its analgesic effect for males, but not females. Murphy says the findings, taken together, suggest that the difference in μ-opioid receptors in the periaqueductal gray explains the sex difference in morphine sensitivity in rats.
A better understanding of underlying neurobiology could one day lead to more effective pain drugs for women, Murphy says, adding that human studies have suggested that morphine produces less analgesia--and more side effects--in women.
"This is ... a breakthrough in finding a viable mechanism of action for sex differences in opiate analgesia in animals," says Richard Bodnar, a neuroscientist at City University of New York, Queens College. Other researchers have suggested that there may be sex differences in opioid receptor number or function in pain-related areas of the brain, but "this work is the first to definitively demonstrate such differences," says neuroscientist Rebecca Craft of Washington State University, Pullman.
Could it also explain differences in opioid sensitivity in people? "There are probably some parallels," says Craft, "but it's a bit early to tell how strong the relationship is between human and animal work in this area."
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FReepmail me if you want on or off my health and science ping list. Happy New Year!
Imagine a half-hour orgasm.....
Imagine a half-hour orgasm.....
A few units in your IV is a wonderful thing... or one of those on-demand things where you’re on a small dose, and can give yourself a booster. Meperadine made me “take the trip without leaving the farm” -
I've got a couple of herniated discs and morphine is the only thing that's getting me through the day right now.
I can't wait to get off of it though as it seems to make the inside of my mouth very sensitive and toothpaste burns like crazy!
Well, Maker’s Mark isn’t too bad by itself.
I'm interested in knowing the reasoning behind increasing raw greens. (I have a couple of herniated discs)
I'm trying a little bit of Yoga and walking on a treadmill. My doctor said no fast walking or running due to the impact it would make. I'm hoping that the slow stretching in yoga help me get off the meds.
I hate opioids. They do not work on me and just mess up my head. Xylocaine doesn’t even work. When I have to get stitches, they shoot me up which take some of the pain away and I just grit my teeth and bear it.
That’s Viagra.
I’ve had several major surgeries and live with severe chronic discomfort.
I am happy to have opiods when i need them though I prefer regular old lortab or percocet to the time released stuff and only take morphine in the hospital.
Now if I had terminal C, then bring it on baby.
Ultram and darvocet don’t do shite.
Of course it works better on men. It affects the BRAIN.
My daughter told me that Dilaudid is the ticket.
I completely agree. I'm lucky enough to have the Morphine IR (immediate release). The time released just doesn't do a thing for break through pain.
My brother recently sent me some reading material which has steered me in this direction. Greens are very rich in vitamins, minerals, fiber, enzymes and amino acids. When we cook them, some of the nutrients are lost to denaturing by heat. We also tend not to eat enough of these foods for our health. I was hoping for an overall boost in immunity and well-being, but not knowing what to expect. I've been happy to have reduced back pain since a few days after adding raw greens to my diet. As I said, it may be coincidence. I tend to eat a lot of vegetables anyway, but I have now increased my consumption of raw dark leafy veggies by whipping them up into smoothies with fruits like bananas, apples, oranges, etc. They look odd, but taste quite refreshing.
Stretching (especially back extensions) has helped me somewhat with herniated disk pain and sciatica. I've also found it helpful to keep up my fluid intake. Disks contain a lot of moisture, and if they're dehydrated, they have less cushioning capacity.
These are all conservative measures which should do no harm, and may do some good. Good luck.
Without Morphine - there would be a lot fewer old men alive today....
This really takes me back . . . When I was in college I had my wisdom teeth removed. The dentist gave me 11 shots of novocaine in the roof of my mouth and 11 in the lower jaw, in an attempt to numb me up enough to remove the wisdom teeth. I still felt everything, starting with the scalpel going in. He got tired of waiting, so he just proceeded with the surgery despite my pain. It was a long time before I went back to a dentist after that, and I never returned to his office. I never made the connection between that and my poor response to other opioids.
I’ve had a few surgeries and the only one I had no post surgery complications with was the one where they used morphine as the pain killer.
You know....I too had 4 impacted wisdoms yanked in 1976 with only a local tooth number like Carbacaine or something
only rich folks went to oral surgeons and got knocked out
today nobody is awake in wisdom pullings
it hurt like all hell, the percodans later were ok though
I've heard about increasing my liquid intake before but had forgotten. First on my list of resolutions this year is getting my back healthy and now I'm going to increase raw greens in my diet!
Happy New Year!
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