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Biotech / Medical : Neurobiological Tech (NTII) -- Ignore unavailable to you. Want to Upgrade?

To: JMarcus who wrote (388)	11/18/1998 9:02:00 PM
From: Dr. John M. de Castro	Read Replies (1) \| Respond to of 1494

Nah, the mode of action of memantine to protect against AIDS Dementia is not completely understood. The mechanism that you write about is one possible route for damage to occur. However, there are a number of others. Regardless, a large subset of damage mechanisms act through the NMDA receptor excitotoxicity mechanism. In other words, the NMDA receptor is the final common pathway for most of the suspected routes for the AIDS virus to damage the nervous system. Memantine is a noncompetitive NMDA receptor blocker. It thus prevents the toxins from initiating the NMDA receptor initiated apoptosis cascade. It is, thus, neuroprotective against the AIDS virus induced damage. What is interesting, is that memantine protects against damage. It does not repair already damaged tissue. But, somehow, the dementia patients seem to be getting better. In theory, all that should happen is that further deterioration should be prevented. In other words, the patients shouldn't get any worse. But, they seem to be getting better. I had a discussion with Stuart Lipton about this. Lipton is the original patent holder of the memantine for neuroprotection patents that NTII has licensed. He is an active and productive researcher in the area. He claimed that the virus was indirectly causing over stimulation of the NMDA receptor in a large proportion of the cells, but not killing them. Thus, when memantine blocked the NMDA receptor, the over stimulation ceased and the cells could begin to respond normally. This is simply theory. But, it is very plausable. I hope that this helps. The picture is far from clear. But, the proof is in the results in real patients and so far these look to be very very good. John de C