A team of researchers from the University of Montreal and McGill University have discovered a type of "cellular bilingualism" – a phenomenon that allows a single neuron to use two different methods of communication to exchange information. "Our work could facilitate the identification of mechanisms that disrupt the function of dopaminergic, serotonergic and cholinergic neurons in diseases such as schizophrenia, Parkinson's and depression,"...
...Their results show that many neurons in the brain are able to control cerebral activity by simultaneously using two chemical messengers or neurotransmitters. This mode of communication is known as "cotransmission." According to Dr. Trudeau, "the neurons in the nervous system – both in the brain and in the peripheral nervous system – are typically classified by the main transmitter they use." For example, dopaminergic neurons use dopamine as a transmitter to communicate important information for many different phenomena such as motivation and learning. The malfunction of these neurons is involved in serious brain diseases such as schizophrenia and Parkinson's. "Our recent research, carried out in part with Dr. Laurent Descarries at the University of Montreal, shows that dopaminergic neurons use glutamate as a second transmitter. That means they are able to transmit two types of messages in the brain, on two time scales: a fast one for glutamate and a slower one for dopamine..."

http://www.eurekalert.org/pub_releas...m-nm031611.php