Human Brain «« Ask an expert

« previous question | all | next question »

Q1: My epilepsy medication information sheet says that "it is thought to work by controlling brain chemicals which send signals to nerves so that seizures do not happen". As far as I am aware chemicals are unable to initiate any signal sending although they may participate in it. My question is: why do we know so very little about how anti-epileptic drugs actually work — is it just like aspirin?
Question submitted by Sean Delaere.

A:Chemicals, called neurotransmitters, can initiate signalling between neurons. If an epilepsy medication increases the signalling of a brain calming neurotransmitter, such as ‘GABA’, then it can reduce seizures. This is how diazepam acts. Other antiepileptic drugs act in different ways to reduce the amount of brain exciting neurotransmitters.

We only have limited knowledge of how many anti-epileptic drugs function. This largely stems from the fact that they are developed using animal models, where seizure reduction is the end point. Only after a drug is seen to be active against seizures do scientists investigate how that drug might be working.

Often, drugs that are developed this way affect more than one mechanism in the brain. This isn’t necessarily a bad thing, but it makes it more difficult to figure out what is the most important anti-seizure mechanism. Because of the enormous complexity of the brain, it also leaves a lingering concern that not all potential beneficial actions of these drugs have been discovered. More recent efforts are using a drug development strategy that is 'target-based'. This means that the starting point is an individual protein in the brain and the drug is made to directly interact with this protein. Once this is achieved, then the tests in animals are done to see if seizures are reduced by this drug. This should lead to a better understanding of how these drugs work and may limit unwanted side effects as an additional benefit.

- Dr Steve Petrou, Senior Research Fellow at the Howard Florey Institute, Melbourne

« previous question | all | next question »

^ top