Neuronal excitability is controlled by inhibitory transmission, which, in the brain, is mostly controlled by the gamma-aminobutyric acid (GABA). Accordingly, to a great extent excitability control involves control of the GABAergic transmission. The latter has two main components: 1) a phasic component, whereby the GABA is released synchronically with the action potentials that enter the GABAergic nerve terminals and 2) a tonic component independent from the presynaptic action potential and which corresponds to continuous inhibition mediated by the GABA at synaptic and extrasynaptic levels. Tonic inhibition depends mainly on the activity of GABA transporters – GATs – which remove […]

The gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the central nervous system. The correct finalization and modulation of GABAergic synaptic transmission occurs thanks to the rapid reuptake of GABA in the synaptic cleft by high-affinity GABA transporters located both in neurons’ presynaptic terminal and in the glial cells, namely astrocytes (1). Until now, four GABA transporters have been identified: GAT-1, GAT-2, GAT-3, and the betaine transporter. The GAT-1 transporter is the predominant GABA transporter in the central nervous system and is preferably expressed in the neurons, although it is equally expressed in the astrocytes (1). It is important […]

Homeostasis of the central nervous system is the result of the balance between glutamate-mediated excitatory transmission and inhibitory transmission, which is mediated by the gamma-aminobutyric acid (GABA). Control of the concentration of neurotransmitters in the synapse, as well as of the time and spatial boundaries of their actions, is vital to ensure correct transmission. This control is guaranteed by specific transmitters expressed in the presynaptic terminal and in the astrocytes surrounding the synapse. With regard to GABA, four transporters (GATS) have been identified up to now: GAT-1, GAT-2, GAT-3 and BGT-1. The ones responsible for GABA reuptake are GAT-1 and […]

In 1791 Luigi Galvani revealed the electrical nature of nerve impulses in frogs’ neuromuscular joints, when he published his masterwork De viribus electricitatis in motu musculari commentarius [1]. Strongly influenced by Galvani’s work, the scientific community defended the concept of bio-electricity up to the beginning of the 20th century, when Ramón y Cajal’s illustrations questioned the possibility of electrical transmission between communicating neurons through perceptible intervals. Afterwards, Otto Loewi’s experiments in vagus nerve preparations led to the discovery of the first neurotransmitter, acetylcholine [2]. This was the beginning of the neurotransmitter concept, an endogenous chemical substance capable of ensuring the […]

Dementias are a set of disorders characterised by memory impairment and at least another cognitive function, which are acquired and have negative repercussions on occupational and social capacities, not occurring exclusively in the course of delirium (American Psychiatric Association, 1994). They are one of the biggest medical problems in present times, given that they are serious diseases, the majority being progressive and incurable. Their frequency increases with age, and as a result of population ageing, their number is very likely to increase (Malgrem, 2000). Among the several risk factors that have been identified for dementias, depression has met with controversy, […]

Professor Ana Sebastião, a researcher at the Institute of Molecular Medicine and at the Faculty of Medicine of the University of Lisbon, together with Professor João Malva, a researcher at the Neuroscience and Cell Biology Centre and President of the Portuguese Neuroscience Society, debated Portuguese research in the field of neurosciences with the public. The debate was moderated by Reginaldo Rodrigues de Almeida, presenter of the Falar Global programme and was held on 31 March at the auditorium of the Knowledge-Living Science Pavilion.   Sónia Barroso Editorial Team sbarroso@fm.ul.pt