Archive for the 'Physiology/Pharmacology' category

And then the smokers came for your sperm...

Today was a lovely day. The weather was perfect, a good day in lab, a good run, a delicious veggie burger, a good beer. Life was pretty much perfect as I sat down in a mood to blog.

...and then I read this paper. And it was like this:

(You know, if only they could have told it to me in a GOOD way...)

There are some papers that you finish reading, and you think to yourself "yup, we're all screwed". I think I have to go find a heartwarming paper about curing cancer now to make myself feel better.

See, first first hand smoke came for your lungs. Then it came for your throat. Then SECOND hand smoke came for your lungs.

...and then they both came after your SPERM.

Marchetti, et al. "Sidestream tobacco smoke is a male germ cell mutagen" PNAS,
2011

I suppose since this is about sperm it should be a Friday Weird Science, but it's just too depressing...

Oh man, now I'm all down and no one will want to read it. I'll try and be perky about it! HONEST! Bad news in a GOOD way!
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11 responses so far

Don't put down the Fritos: Salt cravings and your crack habit.

One of the interesting things about being a scientist is reading how science is interpreted in the mainstream media, and then comparing the headlines back to the science that was, you know, actually done. When I was a young, and highly naive little scientist, I would read the headlines and go "oh, wow, they found that brain structure and hormone use are correlated in women and makes them behave differently. They must have done all of that stuff in the study".

HAHAHAHAHAHAHAAHA. No, no they didn't. At first I was often surprised to find that the media would put all the hypotheses and suggestions in the discussion of the article in as fact, and it turns out that the people doing the study wouldn't have done ANY of those bits AT ALL.

Now, I am not as young (sniff), and I am slightly less naive. So when I saw headlines like "Salt Appetite Is Linked to Drug Addiction, Research Finds", "Cocaine Addiction Uses Same Brain Paths as Salt Cravings", "Appetite for salt linked to drug addiction", I know that you can't ASSUME that they tested the actual drug addiction propensities implies in the studies.

So when you see headlines like this...don't put down the Fritos. Put down the Fritos because those things are gross and probably terrible for you, sure (have you SEEN the fat content on those things?!), but not because they make you a crack junkie.

Liedtke, et al. "Relation of addiction genes to hypothalamic gene changes subserving genesis and gratification of a classic instinct, sodium appetite" PNAS, 2011.

This does not mean this is a bad paper. On the contrary, it's a fine paper. But it does mean, yet again, that you shouldn't believe everything you read.

For starters: "salt appetite" doesn't just mean that you prefer butter style popcorn to kettle corn.


(mmmm, salt. Source)

(And finally a small rant. ", research finds"? ", research finds"?!?! Who the heck thinks that's good sentence structure or in anyway improves the headline?!!? I see this all the time and it always makes me cringe a little. Argh)

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6 responses so far

Concerned about your vole's amphetamine habit? Get them a wife!

Jul 27 2011 Published by under Addiction, Neuroscience, Physiology/Pharmacology

Sci's been meaning to cover this paper for a while, honestly. There is really so much to blog and so little time, you know? I saw this paper make a minor splash when it came out back in June, and I've been wanting to read it myself. And what better way to really READ a paper than to blog it?

So let me introduce the subject of today's paper, the monogamous prairie vole.


(D'awww. Source)

The prairie vole is kind of a darling of the research vole. I mean, it's got nothing on mus musculus, but we do tend to like our voles. They're monogamous! Isn't that sweet! It's cute and easy to breed, and...monogamous! Really, that's the defining feature that makes them interesting, because there really are relatively few species out there other than primates that ARE monogamous. Only 3% of mammals, in fact. So some research has gone in to what it is that MAKES them monogamous, especially when compared to their extremely close cousins the mountain voles.

And then of course, once you've got through all the monogamy issues with the oxytocin and the vasopressin, you start to look at other aspects of this rare kind of social behavior. Things that can be affected by it and things that can affect it.

Things like drugs.

Liu et al. "Social Bonding Decreases the Rewarding Properties of Amphetamine through a Dopamine D1 Receptor-Mediated Mechanism" J. Neuroscience, 2011.

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The Opposite Side of Dopamine: The D2 Receptor

When most people think of dopamine, they think of things that can get you high. Things that feel good. Cocaine. Sex. Food. We imagine floods of dopamine in our brains as the pleasurable feelings take hold. As more and more media outlets cover neuroscience, we get the idea that serotonin means happiness, but dopamine means...pleasure.

And sure, sometimes it does. But dopamine is nothing without its RECEPTORS. And the D2 receptor is one of the big ones. Sure, D2 is a dopamine receptor. But it doesn't mean pleasure, and it's a wonderful example of the ways that the brain uses to put the brakes on such an...addictive system.

This current paper looks at the way we look at D2 receptor function. But it also provides an interesting perspective on possible targeting of those who might be at risk for addiction. Because it turns out, the ability to stop a cocaine binge is only as good as the brakes on your system.

Bello, et al. "Cocaine supersensitivity and enhanced motivation for reward in mice lacking dopamine D2 autoreceptors." Nature Neuroscience. 2011.

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7 responses so far

SCIENCE 101: Cranial Nerve IX, The Glossopharyngeal Nerve

After somewhat of a hiatus, the cranial nerves RETURN! After all, we can't quit now! Only four more to go. And here's where we're at:

Oh: Olfactory
Oh: Optic and Optic 2
Oh: Oculomotor
To: Trochlear
Touch: Trigeminal
And: Abducens
Feel: Facial
Virginia's: Vestibulocochlear and Vestibulocochlear 2
Gucci: Glossopharyngeal
Vest: Vagus
Ah:Accessory
Heaven: Hypoglossal

So we're up to cranial nerve IX, the Glossopharyngeal.

And for function:

Some Say Marry Money But My Brother Says Big Brains Matter Most.

Where the first letter of each word (they are all S, M, or B), corresponds with the functional role, where S is sensory, M is motor, and B is both. So you can see that the glossopharyndeal is going to have both sensory and motor fibers, which is going to make it that much more complicated.

But that's ok. Repeat after me: Glossopharyngeal. Glossopharyngeal. Doesn't it just SOUND nice? Like an onomatopoeia of what happens when a sip of delicious Coca-Cola Slurpee slips over the tongue and fizzes a little at the back.

And speaking of Slurpees...well what did you THINK the glossopharyngeal did?


(Source)

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11 responses so far

REPOST: Oral Contraceptives and Weight Gain, Myths and Truths and Anecdotes

Jul 06 2011 Published by under Physiology/Pharmacology

And lions and tigers and bears!

Sci is reposting this one in particular because I keep seeing it come up. Again and again I read articles on how combined hormonal contraceptives don't cause weight gain. And again and again I see women posting everywhere on the internet not to trust those dang scientists! I gained weight! And so did my friend!

So I'm reposting this one. Because while I'm sure you may have gained weight, you are an anecdote. And so is your friend. No offense.

@noahwg linked an article (or a blog post? It seems more like a blog post) in the NY Times today, on oral contraceptives and weight gain. The post covers a review of various clinical trials (there are only three listed, but that's because they are using the most stringent measures of three treatment trials per study) and concludes that there is no causal association between oral contraceptive use and weight gain.

Yup. Again. Because this isn't news. In fact, it's a reprint of a review released in 2008. Combined oral contraceptives don't cause weight gain in any of the studies in which they've been tested.

I've seen studies like this before, and I commented on it to a female friend of mine. And I got the response I have now come to expect: "Well, I gained weight!"

Sci's gonna have to put on her ranty pants for a minute.


(Someone needs to make these. I would pay good money for these. Source)

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22 responses so far

If you walk over a bed of hot coals, your mom might be worried about you. It’s science.

Sci has to say she’d have LOVED to take the data for this study. Get to go to Spain, hang out, put some heart monitors on people and watch some fire walking…sounds like a good time. Much more glamorous than my own daily life in the lab. Can I get a little glamour around here? The spiffy starched lab coat just isn’t doing it.

Anyway, while this paper involved fire walking, what it’s actually about is the idea of collective rituals, and how they affect the people involved in them. When most people think of collective rituals, they often think of ancient tribes dancing in a circle or something else exotic. But in fact, modern societies engage in just as many collective rituals as we did back when we were all hunter gatherers.

Like that.

(hey, y'all put it on Youtube... and why are all of these in weddings?)

Or that. Collective rituals are things that we do together, whether it’s choreographed dance moves or experiencing a sport. Collective rituals are found in every single society on the planet, and anthropologists think that they are used to foster social assimilation and reinforce a feeling of belonging to the group. The obvious ones that come to mind are things like marching in step, singing, chanting, dancing…and you know, walking on hot coals together.

What? You don’t think that makes you feel closer to people?

Konvalinka et al. "Synchronized arousal between performers and related spectators in a fire-walking ritual" PNAS, 2011

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4 responses so far

SCIENCE 101: Introduction to the Cranial Nerves

I've been waiting for a while to take on another multi-part project (ok, I needed to recover from EB first), and now I think it is TIME. Time for a series SO LARGE that it's going to take me probably more than three weeks, or even four to finish (with breaks for Friday Weird Science, hey, I know what you're really here for). This is going to be INTENSE.

Today I would like to introduce you to the CRANIAL NERVES. When many people think of nerves, they tend to think of white, ropey kind of things which go down your hand. You know, like this:


(Source)

The nerves that we tend to think of are bundles of neurons which extend from the central nervous system to provide impulses to, and receives sensory information from, various areas of our body. Most people think that these nerves extend exclusively from the spinal cord, and that all the impulses that you need travel up and down via the spinal cord. And these nerves certainly exist and you couldn't do a whole lot without them. But what a lot of people don't know is that a large portion of your body is innervated DIRECT from your brain, with nerves that we call the cranial nerves (because they emerge from, you know, the cranium). There are twelve of these cranial nerves, and over the next several weeks, you all will be getting a crash course in neuroanatomy as I go through them in detail, where they come from, where they go, what they are generally responsible for, and what happens when they are not working properly.


(Source)

You can see the twelve cranial nerves listed in the photo above. Numbered 1-12, grad students in neuroscience and medical students in anatomy have to remember them all, as well as their characteristics (luckily for you, there will be no quiz at the end of this lesson!). To help in these we've contrived various mnemonics over the years. My favorites (the ones that aren't horribly dirty) are below.

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14 responses so far

Scicurious GUEST POST: An Optic Cup in a DISH

Apr 20 2011 Published by under Natural Sciences, Physiology/Pharmacology

Today, Sci would like to welcome back to the blog Ambivalent Academic!!! Everyone give her a big hand. 🙂 We were chatting recently about a cool new paper that came out in Nature on corneal formation in a dish, and she said she'd give it a go on my blog!!! So please welcome Ambivalent Academic and her highly awesome post on corneal formation...in a DISH.

Eiraku et al. "Self-organizing optic-cup morphogenesis in three-dimensional culture." Nature. 2011

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16 responses so far

If Stress is Getting you Down, you can blame your BDNF

People react to stress in different ways. Some people seem to thrive under a constant deluge of deadlines, and galvanize to action in the face of life stress. In others, stress can be a trigger for psychiatric disorders such as depression, leaving them feeling helpless and causing difficulties in their everyday lives. But each person is different. So...WHAT is the difference? What makes one person respond well to stress and another shut down?

The answer, in part, may be brain derived neurotrophic factor (BDNF), one of the hot buzz-proteins being thrown around neuroscience circles these days. It's important in depression, in drug addiction, and now, possibly, in stress resistance.

So how do you look at the effects of BDNF on stress? Well, stress some rats. We'll start with a simple Advanced Calculus quiz...


(I love him! He's so cute!!! Source)

Taliaz, et al. "Resilience to Chronic Stress Is Mediated by Hippocampal Brain-Derived Neurotrophic Factor" J. Neuroscience, 2011.

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