Showing posts with label Rats. Show all posts
Showing posts with label Rats. Show all posts

Time To Eat


Our body or circadian clocks regulate the ebb and flow of hormones in our bodies and we readily become creatures of habit. Waking up at the same time in the morning even when we don’t have to or feeling it’s time to eat are just two examples.

Our cats and dogs have even better clocks and your cat will let you know in no uncertain terms if she thinks that you are being slovenly by laying about in bed instead of busying yourself with her dish of cat food. Dogs are so good at anticipating your arrival at home at the end of the day that some people attribute that to doggie ESP.

So what about the nightly life of rats? They are nocturnal and tend to move around nibbling their way through the hours of darkness. However, they can be assigned to the day shift and Mistlberger et al from Simon Fraser U have set about checking the workings of their clocks after they’ve been acclimatized to daytime activity (1).

Now, they were housed indoors and at 2:10 P.M. precisely the lights were switched on when the researchers had finished their lunch breaks. Their first meal was given 3 hours after lights on and their second meal 10 hours after the first.

It didn’t take them long to get used to the timing and they would get into their exercise wheels prior to feeding to work up an appetite. The jogging started about an hour prior to the first meal and about an hour and a half before their second meal. The rats were quite precise about their exercise schedule and didn’t have to be reminded.

The question asked was did their circadian clocks set alarms for this or were they working on a separate interval timer independent of their body clock? A variety of tricks were played on them such as changing the interval between meals, leaving the lights out and not feeding. Of course the tricks weren’t played over long durations so starvation didn’t come into it, just a little healthy fasting.

The results were clear. The rats’ workout schedules were strictly adhered to regardless of changes of feeding practice, clearly showing that they were simply using their inbuilt clocks with a multiple alarm function and not using a separate interval timer or picking up on external clues, and there was certainly no ESP involved.

There is no information about whether the rats are currently unemployed or are engaged in some other major project.


  1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0031772

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Put Your Thinking Cap On


Running around and doing what we like is what we associate with free will. What on earth were you thinking about when you did that is a question that we are sometimes faced with afterwards. Mostly, we don't have any idea. It all went with the moment.

Then as we sit like gods on Mount Olympus watching our lab mice or rats run about in our mazes trying to solve problems, we ask the same question: "what are they thinking?" We can make a start on this quest if we know which parts of their tiny minds are flashing electric pulses from neuron to neuron. The conventional solution is to stick electrodes into the brain and wire the beasties up to computers. However, running around and behaving normally must be hard to do with thick heavy cables hanging off your head.

A new solution is now available. A large multinational team have come up with mouse and rat-sized thinking caps (1). The electrodes are still obligatory, but the hats have multi-channel radio transmitters kitted out with re-chargeable batteries. So after a day or so of running around, the mouse or rat is simply plugged into the lab electricity supply for a while and they're all ready to go on the next set of experiments.

The hats are used to follow the brain activity of, to quote the authors, "freely behaving mice and rats." I'm not sure how freely behaving I would be if I was trying to solve problems with a big hat containing a radio transmitter and battery of the same relative size as their mice are wearing. I would be terribly self-conscious and feeling definitely geeky if not a tad exploited. Certainly, my compensation would have to be increased if I were to play ball.

  1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0022033

A Drop Too Much And Too Often


Whether you are a man or a mouse, or a rat come to that, drinking too much alcohol is bad for you. Many of us have observed at first or second hand the effects of ethanol on the central nervous system. Those effects are over a broader spectrum than we realize. One interaction is with the μ-opioid receptor giving a feel good effect from an increase in dopamine. A study by He and Whistler of U of California (1) has shown a downside to this in that a tolerance to morphine (the μ in μ-opioid) can result.  

The study was carried out with a team of alcoholic rats. These were indulged with an open bar on Mondays, Wednesdays and Fridays when booze equivalent to 50/50 vodka/water was available. Plain water was always on tap as well, of course. On Tuesdays and Thursdays, they were on the wagon. Curiously, no mention was made of their drinking habits over weekends. I guess gentlemen wouldn’t ask about that, after all, they wouldn’t be working and would be on their own time.

The analgesic effect of morphine was checked on both teetotal and alcoholic rats by shining a heat lamp on their tails and measuring the time it took them to flick it out of the way. A maximum of 10 seconds was allowed so as not to produce damage for those enjoying a morphine high.

The first item of bad news for the alcoholic rats is that all that booze reduces the effect of morphine, so they felt the heat. The other item of bad news is that the primary therapeutic for mending alcoholics, naltrexone, is also blocked so they’d be going cold turkey for longer. However, that didn’t end up as their problem; their destiny was elsewhere.

  1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0019372

Singing Mice


With the speculation and rumors around the Oscars at their peak and, indeed, becoming a tad monotonous, we lessor mortals should have foreseen that the American Association for the Advancement of Science would have dedicated a symposium at its Annual Meeting to the subject of stuttering, with three lectures this morning.  The subtitle of the symposium was ‘Untangling the Mystery of Stuttering’ (1)and it is an interesting change from the past in that these newer multidisciplinary approaches are breaking new ground. The Guardian UK gives a detailed account of Dr. Drayna’s presentation (2).

Apparently, there are three genes with particular mutations involved. Mutations in these can result in a deficit of the correct products from the cell metabolism. To test this theory, a set of GM mice have been produced with these three genes inactive. Mr. Mouse bursts into song at the drop of the right pheromone. They sing for minutes and prefer to write their own music. The music is too high pitched for us being just into the ultrasonic but just fine for cats and dogs. If the theory is on target, they will have some very frustrated mice as I don’t expect that the females will come rushing if the singers of the love songs are having difficulty in getting the words out. Drayna’s objective is to design an anti-stutter pill.

The work of du Nil was on a different tack. Using imaging techniques, he has shown that several areas of the brain are involved through differences in activation. This would seem to suggest a fairly complex interaction is at the root cause of a stutter and a pill may be a long way off.

Going up in brain size from mice to rats, a recent neuronal protein study by Dr. Bossert (3) indicated that specific regions of the front part of the brain are involved in drug addiction. Some rat subjects were taught to self medicate with heroin until they were nicely addicted and then they were sent to a rehab unit to clean up. Apart from being a drug-free zone, the quarters became nice and bright and the rats cleaned up their act. However, when back with the sleazy environment, they fell off the wagon. They could get drug help them though by injections of drugs that inhibited the part of the brain wound up by their heroin addiction. I guess you can take the rat out of the street but not the street out of the rat.


1.      http://aaas.confex.com/aaas/2011/webprogram/Session2789.html

2.      http://www.guardian.co.uk/science/2011/feb/20/scientists-create-gm-mice-stuttering

3.      http://www.nature.com/neuro/journal/vaop/ncurrent/full/nn.2758.html