Cellular prion protein (PrPc) plays an essential role in maintaining neurotransmitter homeostasis in the central nervous system. This discovery has been made possible by the observation that both a deficiency and an excess of the protein have a considerable effect on this homeostasis. Surprisingly, in both cases, the central nervous excitability threshold is altered to such an extent that an epileptic seizure may result. Thanks to this discovery, we now have more tools at our disposal that can help us to deepen our basic understanding of epilepsy.
The discovery, carried out by researchers of the Institute for Bioengineering of Catalonia (IBEC) and the University of Barcelona (UB), led by José Antonio Del Río, with the collaboration of researchers at Pablo de Olavide University and the National Institute for Food and Agriculture Technology Research, was presented in a study published in PLoS ONE.
Neurotransmitter homeostasis is achieved through a balance between those mechanisms that excite the neurons of the central nervous system and those that inhibit them. In the study, it was observed in laboratory animals that when PrPc is absent, the excitatory mechanisms are altered and epileptic seizures may occur. As under normal conditions the protein is found in adequate concentrations, it was expected that greater amounts of PrPc would provide greater protection against seizures.. Surprisingly, however, the study showed that this is not the case. With an excessive amount of the protein, the level of excitability of the central nervous system is increased even more than in the absence of PrPc, due to the fact that both the excitatory and inhibitory mechanisms are altered. Such alterations further increase the possibility of suffering severe epileptic seizures. These results allow us to conclude that the protein, when present at adequate concentrations, is essential for maintaining neurotransmitter homeostasis or equilibrium in the central nervous system.