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."
Feminazis will be thrilled.
You mean there might be differences between men and women?
Dewar's works well on me.
The wife hates it.
Sounds like some sadistic researchers, there. First giving rats pleasure, then blocking the opioid receptors and inducing pain.
Muy interesante. Somewhat interesting as well. #1 always told me I was a *ussy when it came to pain. Now then, she was the pillar (salt) of rectitude in child birth, never screaming or fainting so I just assumed she was immune to pain. The divorce filing settled it. The pain question is well-established. Bright red fingernails threatening injury to one’s scrotum are a definite flag that male pain threshold is rather low thus requiring opioid intervention.
My wife thinks that Lagavulin smells like slow-smoked dirty socks stewed in mouthwash. It is medicinal to me, in addition to being incredibly enjoyable.
Weird, I thought it said : Gay Drug...
I must be one of the exceptions. In a recent hospital stay, the powers that be were getting worried about me not taking enuff painkillers.
Morphine has always worked for me.
Crushed L ankle motorcycle accident, shattered R ankle skydiving accident, GSW L forehead, compound fracture L forearm (radius & ulna), broken R hand, dislocated both hips in an equestrian accident, appendectomy, dislocated R shoulder X 2 skydiving, dislocated L shoulder X 2 (quad riding accidents on same day), hernia surgery. I’m only listing major injuries here [;-)
If you are injured remember that the more noise you make in the ambulance the more morphine you get (Demerol (sp?) is a good substitute). Up to their predetermined limit. But if you say nothing you only get the initial dose.
And most important; the ambulance crew won’t remember who you are the next day or tell your friends you wanted more.
If you get hurt morphine is your best most special friend.
Unless you LIKE pain.
Interesting indeed. My husband takes Percocet when nothing else will tame his migraine headaches. He tries to persuade me to take it when I can’t get relief from my own headaches, but I stay away from the stuff. I usually find that it does little for my pain, but makes me violently ill. I always thought it was an individual difference, but perhaps there’s more to it than that.
This has been known for some time, but it was considered to Politically Incorrect to mention. The reason being that men have a lower threshold for pain BUT GREATER TOLERANCE for pain once it starts.
Men have more receptors for pain - but also more receptors for endorphons to numb the pain. Men are “tougher” than women. (If a man were to give birth, the first few labor pains would drive him mad, but then, the endorphons would kick in and he would have something like a “runners high” for the rest of the labor.)
I have learned that narcotics do very little for me, pretty much what you describe. The best pain killer that works on me is naproxyn sodium. After total hip replacement about 18 months ago I dumped the fancy drugs (oxycodone?) two weeks later and took naproxyn soduim. Worked much better.
I have 2 exes and one child with each. Inflicting pain is no longer an issue - as much as they wish they could. Now, I won’t say I couldn’t live without the Xanax after their whacked out phone calls, but, hell, why try to?
Morphine is a gift from God when you need it.
It is not by accident he made poppies for us to use as needed responsibly.
Ask anyone terminal with Big C for starters....
or a compound fracture or herniated or ruptured disc or bad burns or phantom amputee pain etc
and yes i think men are a hair more prone to appreciate sister M
I've been trying a new approach recently. I've increased my intake of raw greens for the past couple of weeks. It seems to be reducing some of my pain from a herniated disk. I'm hoping it's healing and not just coincidence.
Well said.
I'll second that! Three days on that back in August also took away my craving for nicotine, haven't smoked since August 6th and that's after 50 years of cigarette smoking.
Funny thing about that morphine, I was aware there was some pain but I just didn't give a rat's a$$.
15 mg of percoset and a Makers Mark....all is wonderful...la, la, la ...zzzzz...zzzzzz
Probably a good reason why it's a guy drug. Same experience here. Even though it hurts you can go somewhere else (mentally) and let the pain take care of itself.
Before the ladies start in I admit I don't know what it's like for you [;-)
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