An imbalance between neuronal excitation and inhibition may contribute to the early stages of addiction, a paper published in Nature suggests. The finding may prove useful therapeutically.
Excitatory synapses - nerve cell connections that push target neurons to fire more readily - are known to become stronger upon use, a process that is involved in learning and memory. Julie A. Kauer and colleagues show that inhibitory synapses are also able to undergo such 'long-term potentiation' (LTP) in rat brain slices.
The inhibitory synapses, which use the neurotransmitter GABA, signal to dopaminergic neurons in the ventral tegmental area of the rat brain, an area known to be involved in drug addiction. Treating experimental animals with morphine blocks this inhibitory LTP.
The resulting imbalance between excitatory and inhibitory cells may enhance the firing of dopamine neurons and so fuel the addictive process. Drugs that target the relevant GABA receptors may interfere with this process.
Julie A. Kauer (Brown University, Providence, RI, USA)
Wendy Lawton (Media Relations, Brown University, Providence, RI, USA)
(C) Nature press release.
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