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Medical News Today: Catnip: What do we know about the feline drug?

The internet is rife with funny cat videos showing their reactions to a plant commonly known as "catnip." What is catnip, does it affect all felines, is it safe for cats, and should humans use it? This Special Feature investigates these questions and more.

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Does your feline friend go crazy for catnip? In this Special Feature, we find out why — or why not.

Nepeta cataria, or "catnip," is an herb belonging to the same plant family as mint. Although it originated in parts of Europe and Asia, the plant is now common across several continents, including North America.

Because, like regular mint, catnip proliferates easily, many cat owners grow the plant in pots as a special treat for their feline friends.

As part of the mint family, fresh catnip also smells minty, though this is not the case for the dried catnip sometimes present in commercial cat treats or toys, which may smell more like dried grass.

Why is catnip such a special treat? People who share their life with a cat will know that this plant often has a marked, and sometimes very funny, effect on these beloved animals — not unlike the effect that a mild recreational drug might have on humans.

Do all felines react to catnip? Why does this plant affect cats, exactly? Is it really akin to recreational drugs? Read on to find out.

1. Why does catnip affect cats?

In his book Intoxication: The Universal Drive for Mind-Altering Substances, psychopharmacologist Ronald Siegel estimates that around "70% of domestic cats respond to catnip," and that those who do have reached sexual maturity. Cats reach sexual maturity at around 6 months of age.

Cats who react to catnip will sniff the plant, or any toys that contain it, and then start chewing on it. Following this, they may start rubbing their head against the plant or toy, and then roll or flip from side to side.

"Both of [my cats] love it, and it makes them go crazy," one reader told Medical News Today. "[The female] likes to lick it, then she attacks the toy it's on, often adopting the bunny leg attack. [The male] goes more soppy with it, often rolling around with the toy in his paws," they said.

Although in most cases, when it does affect them, catnip stimulates cats in a pleasurable way, the American Society for the Prevention of Cruelty to Animals deem it "toxic to cats." They warn that some domestic felines may experience adverse reactions after coming into contact with this plant. These effects can include vomiting and diarrhea, as well as states of sedation.

Some cats may even become aggressive when they encounter the plant. Another reader told MNT that she avoids giving her cat any catnip for this very reason. "[My cat] just gets a bit like she wants to fight me [and] starts punching my foot," they said.

For the many cats that respond well to catnip, Siegel notes, this may be "an example of animal addiction to pleasure behavior." Both male and female cats respond to catnip in a way that is reminiscent of sexual arousal among these felines.

Because of these similarities, some researchers have suggested that the plant may once have been a timely and natural enhancer of reproductive behaviors.

"These displays have prompted naturalists to speculate that catnip once served the evolutionary function in the wild of preparing cats for sex, a natural springtime aphrodisiac."

Ronald Siegel

He explains that the molecules that carry catnip's scent, called terpenoids, are what causes the reaction. Catnip features a specific type of terpenoid called nepetalactones. These molecules, Siegel explains, can be toxic. However, they are usually harmless in the quantity in which they are present in catnip.

Cats absorb nepetalactones by sniffing the catnip. The molecules then bind to olfactory (smell) receptors in the nose, which send additional signals to the amygdala, which are two small clusters in the mammal brain. These are linked with both the regulation of emotions and some sexual behaviors.

2. Why do some cats not respond?

About 30% of domestic cats have absolutely no reaction to catnip. One MNT reader exclaimed that it "has no effect on [her cat] whatsoever!"

Why does catnip affects some cats but not others? The difference, Siegel argues, lies in cat DNA. Some cats inherit the "catnip sensitive" gene, while others simply do not.

"The reason for the failure of some cats to become even the least bit excited about catnip and for the exaggerated reaction of others is genetic," he writes.

"Cats can inherit a dominant gene that guides the reaction to catnip," adds Siegel. He adds that some studies have demonstrated that the offspring of cats sensitive to catnip are also sensitive to this plant, and that those of cats with no reaction to it also will not respond.

In addition to this, he says, some felines may become avoidant of catnip if they have had a bad experience with it.

For instance, notes Siegel, if a feline has sniffed or chewed on catnip and then injured itself, in the future, it may turn around when encountering the plant, instead of jumping at the occasion of accessing the stimulant.

3. Does catnip affect other felines?

If catnip can have a striking effect on domestic cats, does it also affect larger felines, such as lions, jaguars, and tigers?

The answer is "yes" — and it seems to act, to a much lesser extent, on other cat-like mammals that are not actually felines.

An experiment conducted in the early 1970s at what is now Zoo Knoxville in Tennessee found that lions and jaguars were "extremely sensitive" to catnip.

Some of the tigers, cougars, and bobcats at the zoo also responded to catnip, though not at all strongly. The two cheetahs on site at the time showed no interest in the plant.

Other animals have shown curiosity about catnip, though to a much lesser extent than domestic cats.

Non-felines that have shown an interest in catnip include civets, which are carnivorous animals native to Asia and Africa that look like cats but belong to a different family, called Viverridae.

4. What other stimulants affect cats?

Though catnip is by far the best known cat stimulant, researchers have noted that there are many other plants that can alter felines' moods and behaviors.

Siegel, for instance, speaks of matatabi, or silver vine (Actinidia polygama). This is a plant native to areas of Japan and China. In an experiment at Osaka Zoo in Japan, large felines exposed to high quantities of the active substance in matatabi showed signs of intense pleasure — and addiction.

"This plant contains secondary compounds closely related in chemical structure and behavioral activity to nepetalactones," Siegel explains.

"After an initial exposure, the [large] cats became so eager for more that they would ignore whatever else they were doing — eating, drinking, or even having sexual intercourse — whenever the chemicals were made available."

Ronald Siegel

One 2017 study confirmed that matatabi can be just as, if not more, effective than catnip when it comes to stimulating domestic cats.

The study's authors also identified two more plants that had a similar effect: Tatarian honeysuckle (Lonicera tatarica) and valerian (Valeriana officinalis).

Almost 80% of the domestic cats in this study reacted to matatabi, and around 50% of cats also responded to Tatarian honeysuckle and valerian root.

Matatabi, the study authors also note, actually elicited a response in 75% of the domestic cats that had no reaction to catnip.

"Olfactory enrichment using silver vine, Tatarian honeysuckle, or valerian root may, similar to catnip, be an effective means to improve the quality of life for cats," the researchers conclude.

5. Is catnip safe for humans?

Although humans tend to buy or cultivate catnip purely for the entertainment of their feline friends, some people think that the plant can have a soothing effect on their own minds.

For example, some people like to brew catnip tea, and some have even tried rolling the plant into cigarettes and smoking it. "It makes people feel happy, contented, and intoxicated, like marijuana," an older study notes.

As a supplement, people have also used catnip to treat symptoms such as coughs or toothaches, and as a digestive aid.

Is it safe? This much remains unclear. So far, there has been little research into the effectiveness or safety of catnip when it comes to treating various conditions in humans.

Some specialists suggest that catnip can cause contractions of the uterus, so they recommend that pregnant women avoid this plant.

Given the scarcity of evidence regarding the safety of this plant, however, our readers may be better off saving it for their cats' enjoyment — that is, if they are part of the majority that do appreciate it.

Original Article

Medical News Today: Could probiotics benefit cats?

Probiotic supplements have become increasingly popular in the United States, and a recent study asks whether cats could benefit from them. Though the results hint at certain benefits, the authors call for more work.

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A recent study asks whether probiotics might improve feline gut health.

Now available in a range of products, including drinks, breakfast cereals, and yogurts, probiotics promise improved digestive and overall health.
However, scientific support for these claims is scant, though research indicates that probiotics can help treat or prevent some specific conditions, such as antibiotic-associated diarrhea.

Regardless of the sizable holes in the evidence, the use of probiotics in the United States quadrupled from 2007 to 2012.

Although scientists are skeptical about the benefits of commercially available food-based probiotics, there is no doubt that the bacteria that reside in the mammalian gut are vital for the health of the gut and beyond.

As the authors of a recent study explain, gut bacteria can boost an animal's immune defenses, improve digestion, and aid energy metabolism.
Conversely, studies have shown that in cats and dogs, dysbiosis — alterations in the normal gut flora — can cause intestinal inflammation and stress-associated diseases.

Probiotics and fecal quality

Recently, a group of researchers decided to investigate whether a probiotic could influence "nutritional conditions and fecal quality in healthy cats."
They decided to investigate this topic because, "Although several scientific studies reported beneficial effects of probiotics on gut health in human beings and dogs affected by [gastrointestinal] disorders, few studies on cats have been performed."

In farmed animals, probiotics are used to increase production and, as the authors explain, there is "an increasing interest in their supplementation in human and companion animals' diets."

To investigate, the researchers selected 10 healthy adult Maine Coon cats. The scientists fed all of the animals the same diet, and they gave five of the cats a strain of the bacterium Lactobacillus acidophilus. This species is common in cats, dogs, and humans.

The scientists published their findings in the BMJ journalVet Record Open.

Earlier studies have found that L. acidophilus boosts the performance of egg-laying hens and improves chickens' gut health.

Assessing improvements

Throughout the 5-week trial, the scientists weighed the cats. They also checked their body condition using the Nutritional Assessment Guidelines for Dogs and Cats, which was designed by the American Animal Hospital Association.

The authors explain that this method is "the most widely used method for assessing cats' nutritional status."

The scientists also assessed fecal firmness using the Nestle Purina fecal score system and measured fecal moisture levels in the laboratory. These assessments are considered a good measure of an animal's gut health.

All of the cats remained healthy throughout the study, with no side effects, and maintained an ideal body composition. Similarly, the scientists found no difference in weight among cats in the control and probiotic groups.

However, the feces of cats in the probiotic group was less moist and of a higher "quality" than that of the control cats. Overall, the authors conclude that "Cats in the [probiotic] group showed drier feces, compared with cats in the [control] group."

As expected, the feces of the cats in the probiotic group contained higher levels of L. acidophilus, which indicates that the supplementation was having the desired impact.
The feces produced by the felines in the probiotic group also had lower levels of coliform bacteria such as Escherichia coli — indicating, the authors believe, "that probiotics have a slight protective effect on invasive bacteria species."

Of course, a study involving just 10 cats over a handful of weeks does not provide enough evidence for solid conclusions. Scientists will need to do much more research before they can assess whether there are any true benefits.

It is worth noting that, as the authors write, "The possible causes of soft feces in cats and dogs are still debated."

Also, all of the animals were healthy and remained so throughout the study; the authors write:

"Further studies with a larger sample of healthy cats and a comparison with cats experiencing [gastrointestinal] pathology could be carried out to investigate the effect of the tested strain on carnivore dysbiotic gut."

Although the stool quality of the cats in the recent study was improved by some measures of gut health, this does not mean that, overall, the cats who received probiotics were healthier.
As with probiotics for human use, this area needs much more research.

Original Article

Medical News Today: Why are baby pandas so small? Study explores

An unusual study explores a question that has puzzled researchers for a long time: Why are giant pandas so tiny when they are born?

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Baby pandas only weigh about 100 grams at birth.

Kathleen Smith, a biology professor at Duke University in Durham, NC, and her former student Peishu Li, conducted the new research, which appears in the Journal of Anatomy.

There are a lot of intriguing — and somewhat endearing — facts about baby pandas.

For one thing, the giant panda newborns are particularly "helpless." They are born blind, pink, and hairless. They do not open their eyes until they are 6–8 weeks old, and they cannot move before the age of 3 months.

The cubs do not leave their mother's side until they are between 1.5 and 3 years old — out of a lifespan of about 20 years.

Furthermore, giant panda babies are 900 times smaller in size than their mothers. They only weigh about 100 grams at birth.

With the exception of opossums and kangaroos, giant panda newborns are the smallest mammal babies compared with their mother's size.

But why is that? To find out, Smith and Li examined skeletons from baby pandas that had been born at the Smithsonian's National Zoo in Washington, D.C.

Studying pandas' skeletons

The prevalent theory for explaining small birth size relies on the fact that pregnancy occurs at the same time as winter hibernation in some species.

During hibernation, pregnant mothers rely on fat reserves to survive, so they do not eat or drink. They also break down muscle mass to feed protein to the fetus.

However, such a process can only be short-lived before it poses a threat to the mother's health. In other words, the energy resources are limited, so the babies must be born prematurely, resulting in small cubs.

Although pandas do not hibernate in winter, those who support this theory contend that small birth weight is a common trait that genetics predetermines in the so-called Ursidae family — a family that comprises eight species of bears across five genera, ranging from brown bears to giant pandas.

To test if this theory was correct, the authors of the new study set out to compare several species.

Giant pandas' bones not mature enough

The researchers took micro-CT scans of giant panda babies, as well as other related animals, including baby grizzlies, sloth bears, polar bears, red pandas, domestic dogs, an African wild dog, and an arctic fox.

They then used the micro-CT scans to create 3D digital models of the animals' skeletons. The researchers looked at how much of the skeleton had ossified before birth, whether teeth had started to erupt, and examined the fusion between the neural arches, that is, the bony plates that make up the skull.

Even though Smith agrees that the prevalent theory is "an interesting hypothesis," the researchers' findings did not seem to support it.

The scientists failed to find any differences between hibernating bears and their nonhibernating relatives when it came to bone growth. Despite the small size, most bear skeletons showed a similar degree of maturity at birth as their relatives, with giant pandas being the only exception.

Full-term baby pandas resemble a "28-week human fetus" in terms of bone density and maturity at birth, says Smith.

'Development is just cut short'

The scientists do not yet know the answer to this question, but they do know that baby pandas seem to mature at the same pace as other mammals, at least judging by their skeletons.

The only difference is that "Development is just cut short," according to Smith. Giant pandas' relatives gestate for 2 months after the egg's implantation, whereas panda bears only do so for 1 month.

"We really need more information about their ecology and reproduction in the wild," the author adds, pointing out that their findings only involve the bones. Looking at other organs, such as the brain, might reveal new and different theories.

Original Article

Medical News Today: For rats, empathy may be a survival strategy

New research suggests that a rat's experiences may act as an early warning system to its fellow rodents.

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New research sheds light on the mechanism of empathy in rats.

Empathy is the ability to understand someone else's emotional experiences. Typically, we think of empathy as a noble quality that we relate to compassion.

However, a new study from the Netherlands Institute for Neuroscience in Amsterdam suggests that for rats, being able to detect another's feelings may be a vital survival tool.

"What our data suggest is that an observer shares the emotions of others because it enables the observer to prepare for danger. It's not about helping the victim but about avoiding [becoming] a victim yourself."

Valeria Gazzola, senior author

The research suggests that empathy tells a rat what lies ahead; another rat's fright or pain may serve as an early warning, while their happiness could suggest the "all clear."

The new research appears in the journal PLoS Biology.

The experiments

The authors of the study examined empathy in a series of experiments and drew several conclusions about the manner in which rodent empathy works.

The researchers were also interested in ascertaining the factors that might create greater empathy.

The experiments positioned pairs of rats face-to-face. The scientists designated one rodent as the "demonstrator" and the other as the "observer" or "bystander."

In each round, the demonstrator was startled by the brief application of electrical current to their front paws as the observer watched.

"The first thing you see is, upon witnessing its neighbor jump, the bystander suddenly looks scared as well. The bystander catches the fear of the demonstrator," according to author Rune Bruls.

"Fear just jumps from one rat to another," Bruls adds, and the fear also jumps back. The researchers saw that the observer's reaction also affected the demonstrator's feelings about the electrical current.

The suggestion is that the observer's level of fear provided a clue to the demonstrator — the rat that had experienced the shock firsthand — how to feel.

If the observer did not seem that scared, then neither did the demonstrator. If the observer was terrified, so was the demonstrator.

How familiarity, experience affects empathy

People may assume that the closer they are to another, the more readily empathy will occur. It turns out this is not the case, at least for rats.

By comparing the empathetic responses of rats that had never met before against other pairs that had shared a living space for 5 weeks, there was no difference in the speed or intensity of the emotional contagion, according to the paper's authors.

Gazzola considers this finding as supportive of the empathy for survival hypothesis: If survival is a rat's main concern, the relative familiarity of a partner would be of little consequence.

One factor that did have an impact on empathetic response was an observer's own previous experience with electrical shocks.

Observers unfamiliar with the experience were less likely to react to a demonstrator's plight in a big way.

Efe Soyman, another of the study's authors, suggests: "Rats are like humans: The more our experiences match those of the people we observe, the more we can empathize with what they feel. It takes one to know one!"

Rats vs. humans

The research team was able to use the rat experiments to make a connection with the brain area scientists associate with empathy in humans, called the anterior cingulate cortex (ACC).

To see if the rats' ACC was similarly involved in empathy, the researchers introduced a drug that temporarily reduces activity in the area.

"What we observed," says Prof. Christian Keysers, lead author of the study, "was striking."

"Without the region that humans use to empathize, the rats were no longer sensitive to the distress of a fellow rat. Our sensitivity to the emotions of others is thus perhaps more similar to that of the rat than many may have thought."

Christian Keysers

After all, rats are not the only species that wants and needs to survive.

Original Article