Posted by SLS on October 1, 2005, at 22:37:01
In reply to Re: Does Ectasy Cause Brain Damage and Depression? » SLS, posted by Shawn. T. on October 1, 2005, at 18:53:05
Hi Shawn.
> On the matter of neurotoxicity, I feel that people, especially non-scientists, often jump to conclusions about evidence that they haven't carefully considered.
I'm sure some people do. I'm sure some people don't. I'm betting on our neuroscientists to carefully consider the evidence while that evidence evolves as our experiments are refined and our understanding expands.
> According to Rothman et al. (2004) at the National Institute on Drug Abuse, D-fenfluramine and parachloroamphetamine "did not change expression of glial fibrillary acidic protein (GFAP), a hallmark indicator of neuronal damage,
Are there any other putative indicators that they did not assay for that perhaps don't depend on glial cells to reflect?
> These results support the hypothesis that D-FEN- and PCA-induced decreases in tissue 5-HT and SERT binding sites reflect neuroadaptive changes rather than neurotoxic effects."
Interesting way of looking at things. This might be very true. However, this one aspect of neuronal function and adaptation does not exclude the possibility that toxic events are not localized elsewhere in the neuron. What about the synaptic vesicles, their transporters, and the areas of the terminal membrane upon which they fuse? Perhaps more importantly, if the reduction in transporter numbers is also reflected in synaptic vesicles, there might be an inability for the neuron to sequester neurotransmitter at a rate high enough to prevent its oxidation in the cytosol and the subsequent release of free radicals that produce a degeneration of neurites. I don't happen to know if GFAP acts as an index of this type of neurotoxicity.
In the absence of absolute knowledge and understanding, I guess it becomes an exercise in logic as to what we may conclude absolutely. If GFAP appears, we have neurotoxicity. If GFAP does not appear, we don't?
Devil's advocate.
- Scott
poster:SLS
thread:560483
URL: http://www.dr-bob.org/babble/20050927/msgs/561775.html