First of all I'd like to thank everyone who wishes me a happy birthday, you guys are great, I really appreciate it. I will try very hard to get back to everyone who did, though it's going to take a me while, I think.
Last night was fun, it was just what I was looking for. Skryche, vyeseleph, luckyP, Johnnysanasshole, luna, and champagneofdudes met up with me to have drinks at the trashtacular Bar 81 in the east village. Bush's speech at the RNC was going on at the time, and they had it on the TV so of course we turned it into ao drinking game - every time he said "terror," "terrorists" or "September 11th" everyone had to take a drink. We made it through our beers awfully quickly.
Thankfully the RNC is now over, which means all of the bowtie-wearing, blue blazered, crusty, old, white guys have left the city and it's returning to some semblance of the way it used to be. It was a bit of a shock today though, when I got to hospital where my lab is there was a giant media circus outside - I learned later that Bill Clinton is there right now having quadruple bypass surgery. I hope he gets better, I'm a big of him and his wife.
In other news, my last journal entry described in fairly disgusting detail an experiment I had been working on the previous weekend. (check that entry if you want to understand what I'm about to write.) In that entry I described how I didn't see any increase in the frequency of glutamatergic synaptic transmission after applying nicotine to my cells, which was surprising and a little disappointing. In preparing for my meeting today with my advisors though, I took a few hours and pored over the data more closely. What I found was even more surprising, but in a good way.
The frequency of spontaneous miniature events either did not change or decreased slightly in most of the preparations that I looked at (the one exception being the one where there was no activity until I applied nicotine and then there was robust activity - I'm still not really sure what to make of that data.) What I noticed this time, however, was that the amplitude of the events was increased after nicotine. But not universally - the spikes seemed to fall into two categories, either exactly the same size as before nicotine, or about twice as big as those spikes (occasionally I saw one that looked roughly three times as big, but that was rare.)
I'm going to backtrack for one second to try and explain what the hell it is that I'm talking about. When you add tetrodotoxin to cells it stops all action potentials, or nerve impulses, from firing. If you're recording electrical activity from a postsynaptic cell, that means all you'll see is what is termed "miniature spontaneous release." That is - synaptic vesicles in the presynaptic cell normally are released in a giant burst when an incoming action potential hits them. In the absence of an action potential there is still a probability that one of those vesicles will be released on its own - this probability varies from synapse to synapse. Nicotine has been shown to increase the release probability of these presynaptic vesicles by locally increasing the calcium concentration in the presynaptic cell (that's the essence of presynaptic facilitation, which I talked about last time.) That has generally been interpreted to mean that there will be more release events.
A controversial paper published in the journal Neuron last year indicated that under certain circumstances they observed nicotine increasing the facilitation of what they called coincident release. One of the reasons it was controversial is that the authors are not really electrophysiologists, and so many of their methods are flawed. Had I reviewed the paper I probably would have rejected it, but that's neither here nor there. This coincident release means that through facilitation multiple synaptic vesicles will be released simultaneously. Again, it's very difficult to prove, and there are only a handful of papers out there to support it, but it's what some people are claiming.
And it seems to fit with my data. There are some other possibilties that I need to rule out before I can say it's what I have for real (and, of course, the experimental data need to be replicated) but if it turns out to be true it would be incredibly cool.
So again, I'm feeling pretty good about my research. I've got two potentially interesting results to come out of a single experiment, which is way more than I can usually say. As anyone in science knows, the hardest thing to do is replicate an interesting result, but there's not much else I can do at this point.
I hope everyone has a nice weekend, and I promise a non-science journal entry for the next time.
Last night was fun, it was just what I was looking for. Skryche, vyeseleph, luckyP, Johnnysanasshole, luna, and champagneofdudes met up with me to have drinks at the trashtacular Bar 81 in the east village. Bush's speech at the RNC was going on at the time, and they had it on the TV so of course we turned it into ao drinking game - every time he said "terror," "terrorists" or "September 11th" everyone had to take a drink. We made it through our beers awfully quickly.
Thankfully the RNC is now over, which means all of the bowtie-wearing, blue blazered, crusty, old, white guys have left the city and it's returning to some semblance of the way it used to be. It was a bit of a shock today though, when I got to hospital where my lab is there was a giant media circus outside - I learned later that Bill Clinton is there right now having quadruple bypass surgery. I hope he gets better, I'm a big of him and his wife.
In other news, my last journal entry described in fairly disgusting detail an experiment I had been working on the previous weekend. (check that entry if you want to understand what I'm about to write.) In that entry I described how I didn't see any increase in the frequency of glutamatergic synaptic transmission after applying nicotine to my cells, which was surprising and a little disappointing. In preparing for my meeting today with my advisors though, I took a few hours and pored over the data more closely. What I found was even more surprising, but in a good way.
The frequency of spontaneous miniature events either did not change or decreased slightly in most of the preparations that I looked at (the one exception being the one where there was no activity until I applied nicotine and then there was robust activity - I'm still not really sure what to make of that data.) What I noticed this time, however, was that the amplitude of the events was increased after nicotine. But not universally - the spikes seemed to fall into two categories, either exactly the same size as before nicotine, or about twice as big as those spikes (occasionally I saw one that looked roughly three times as big, but that was rare.)
I'm going to backtrack for one second to try and explain what the hell it is that I'm talking about. When you add tetrodotoxin to cells it stops all action potentials, or nerve impulses, from firing. If you're recording electrical activity from a postsynaptic cell, that means all you'll see is what is termed "miniature spontaneous release." That is - synaptic vesicles in the presynaptic cell normally are released in a giant burst when an incoming action potential hits them. In the absence of an action potential there is still a probability that one of those vesicles will be released on its own - this probability varies from synapse to synapse. Nicotine has been shown to increase the release probability of these presynaptic vesicles by locally increasing the calcium concentration in the presynaptic cell (that's the essence of presynaptic facilitation, which I talked about last time.) That has generally been interpreted to mean that there will be more release events.
A controversial paper published in the journal Neuron last year indicated that under certain circumstances they observed nicotine increasing the facilitation of what they called coincident release. One of the reasons it was controversial is that the authors are not really electrophysiologists, and so many of their methods are flawed. Had I reviewed the paper I probably would have rejected it, but that's neither here nor there. This coincident release means that through facilitation multiple synaptic vesicles will be released simultaneously. Again, it's very difficult to prove, and there are only a handful of papers out there to support it, but it's what some people are claiming.
And it seems to fit with my data. There are some other possibilties that I need to rule out before I can say it's what I have for real (and, of course, the experimental data need to be replicated) but if it turns out to be true it would be incredibly cool.
So again, I'm feeling pretty good about my research. I've got two potentially interesting results to come out of a single experiment, which is way more than I can usually say. As anyone in science knows, the hardest thing to do is replicate an interesting result, but there's not much else I can do at this point.
I hope everyone has a nice weekend, and I promise a non-science journal entry for the next time.
VIEW 25 of 28 COMMENTS
Very interesting results. I suppose a lot more data and a few statistics should help figure out whether you have results consistent with synchronous vesicle release or an increase in the response on the postsynaptic side. I would imagine either way would be novel for the CNS, and therefore a good result.
By the way, nice wig-busting.