04 June 2007

Getting to Ampakines--How Much Longer?

Brain boosting drugs in the new Ampakine class are back in the news--this time in connection with the problem of respiratory depression from sedative/hypnotic drugs.
Researchers at the University of Alberta (Edmonton, AB) and Cortex Pharmaceuticals (Irvine, CA) believe that AMPAKINE drugs may provide protection from drug-induced respiratory depression, while simultaneously allowing the sedative or analgesic to continue working as it was intended.

The drug tested in this study belongs to a novel class of molecules known as AMPAKINE compounds being developed by Cortex Pharmaceuticals, Inc. located in Irvine, California. AMPAKINE compounds act on the most common excitatory receptor in the brain, the AMPA "Glutamate type receptor," which has been shown in rodent models to boost the brain's own protein for improving age-related deficits in memory mechanisms. In primate models AMPAKINE compounds have replicated the studies in rodents and in adults patients suffering from Attention Deficit Hyperactivity Disorder, significant clinical and statistical improvement in increase attention and decrease hyperactivity have been observed. The U. Alberta research provide evidence that another important AMPAKINE indication is to stimulate primitive areas of the brain called the pre-Botzinger Complex responsible for breathing, without causing side effects. The pre-Botzinger Complex generated respiratory-related oscillations similar to those generated by the whole brainstem in vitro, and neurons with voltage-dependent pacemaker-like properties that have been identified in this brain region.

In a study published in 2006, Dr. John J. Greer of U. Alberta demonstrated that certain AMPAKINE compounds enhance the respiratory drive and breathing rhythm at the brain-stem level containing the pre-Botzinger Complex in laboratory rats whose respiration rates were purposely suppressed by administration of central nervous system depressants.

Dr. Greer found that respiratory depression induced by these agents can be reversed or prevented in test animals with an experimental AMPAKINE drug, without a reduction of pain relief or sedation.

Greer and coworkers treated rats with the opioids analgesic fentanyl or the barbiturate sedative Phenobarbital, both commonly prescribed in the United States. Greer used a technique known as plethysmography, which measures blood flow throughout the body, to determine the level of respiratory distressed caused by the drugs. When drugged rats were treated with the AMPAKINE , the respiratory distress quickly resolved. The drug worked in both newborn and adult rats. Interestingly, the drug on its own did not affect blood flow in animals not treated with the sedative drugs, nor did administration of the drug cause noticeable arousal in the animals.

Greer concluded, in a study published in the September 20, 2006 issue of the American Journal of Respiratory Critical Care Medicine, that CX546, "effectively reverses opioid- and barbiturate-induced respiratory depression without reversing the analgesic response."

"These results open up the real possibility of combining an ampakine compound with commonly prescribed barbiturates or opiates to reduce the likelihood that life-threatening respiratory depression will occur," noted explained Roger G. Stoll, Ph.D., Chairman, President, and CEO of Cortex.

Ampakines hold out a promise for effective palliative treatments for Alzheimer's and other neurodegenerative disease. Currently, the Cortex drug CX717 is being held up by the FDA over toxicity concerns. Consequently the stock price of Cortex is currently quite low--trading below US $3 a share for over a year.

It is easy to see that should Cortex navigate through the labyrinthine bureaucracy of the FDA and reach approval for any of its Ampakines in development, that the stock price could rise rapidly.

Frankly, it is the potential for cognitive enhancement in normal people that fascinates me the most about the Ampakines. But the potential to make a substantial profit on a fairly small investment is also attractive. But do your own research before investing.

Here is more about Cortex' attempt to satisfy the FDA's concerns about possible toxicity of CX717 in animal studies.

Here is a recent report on a study that suggests that Ampakines might benefit Huntington's Disease patients, through their role in releasing BDNF in the brain.

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