February 16, 2008

A Vaccine To Crack The Cocaine Bugs

a synapse with neurotransmitters and receptorsYears ago I heard the song "Snowblind" by our one and only Ozzy Osbourne, from his album Speak of the Devil. The meaning of the song is two-fold. Firstly, people in a snowy landscape face such intense reflection of sunlight, that they might go blind. They wear special goggles to restrict sunlight, so that it doesn't burn the macular portion of the retina (the part where light rays are usually focussed.)

Another interpretation of this song could be this that someone gets blinded by the actions of cocaine (also known as snow or crack). That's precisely what Ozzy meant.

Cocaine, an alkaloid obtained from the leaves of Erythroxylum coca, produces euphoria (a feeling of elation) by increasing the amount of dopamine in the brain. Dopamine is normally liberated in brain structures such as the basal ganglia.animation of neurotransmitter release and action After it has been liberated and it has finished its action, residual dopamine in the synapse is 'cleared' by dopamine transporters in a process called reuptake. These transporter proteins packs these chemicals back into where it came from (into the axon, as is shown in the picture), hence re-uptake. Cocaine binds with these transporters in such a tight embrace that these transporters fail to function: that is, cocaine functions as dopamine reuptake inhibitor. Dopamine, the pleasure (reward) chemical, which now accumulates in the synapse, gives the person a good kick. Frequent use of it through inhalation or injection (as these routes lead to faster absorption) gives them the feeling of an orgasm, which users refer to as 'rush'. Nucleus Accumbens, an area in the brain, supposedly 'reinforces' this addiction.

So isn't there a way out? Will they have to go on scratching their skin (cocaine produces a typical dermal itching sensation, Magnan sign or the cocaine bugs, where the patient feels as if insects are crawling under their skin)? Scientists are now on the verge of producing a vaccine (TA-CD Vaccine), which not only will cure their addiction but also decrease the severity of its 'withdrawal symptoms'. The human immune system can not recognize cocaine since it is a small molecule. Hence, they are combining parts of inactivated cocaine molecule with inactivated cholera proteins. After you give them a 'shot' of this vaccine, the immune system will now recognize the combine and produce antibodies against coke. Next time cocaine is consumed, the antibodies in the blood will combine with the cocaine molecule and prevent it from reaching the brain, its main seat of action. The vaccine is currently undergoing clinical trials.

Not only cocaine, vaccine is being developed against methamphetamine too (N-methyl amphetamine), another drug of abuse. The mechanism of action of the vaccine is the same. These drugs are still used in clinical practice: cocaine as an anesthetic; methamphetamine analogs, methyl phenidate (RITALIN) and pemoline are widely used in attention deficit hyperactivity disorder or ADHD. But keeping in mind their abuse potential, these drugs should be prescribed weighing the risk-benefit ratio. And when an addiction has already developed, we must cure it, may be by using a vaccine like this.

Last modified: 13 Jul 2009
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