European Journal of Biomedical and Pharmaceutical Sciences

ROLE OF ASTROCYTES IN NEUROPHARMACOLOGY

Dibyendu Dutta*, Rahul Kumar Singh, Jaydeep Roy, Falguni Dutta, Rishav Banerjee and Dr. Dhrubo Jyoti Sen

ABSTRACT

Astrocytes are a heterogeneous class of neuroectodermally derived glial cells that arise from the neural crest and are present in the central nervous systems of all vertebrates. Although the subtypes of astrocytes described above, namely fibrous, protoplasmic and Layer-1 astrocytes, are widely found in mammalian brains, there are at least two specific subtypes for human or other primates. Astrocytes (from Ancient Greek ἄστρον, ástron, "star" and κύτος, kútos, "cavity", "cell"), also known collectively as astroglia, are characteristic star-shaped glial cells in the brain and spinal cord. Astrocytes regulate metabolic homeostasis through synthesizing glycogen and supplying neurons with energy substrates. Astrocytes define the cytoarchitecture of the grey matter by tiling the latter and by forming contacts with the vasculature by vascular end feet and by glial sheets at all surfaces of the brain. Astrocytes contribute to the maintenance of the health and function of the central nervous system (CNS). Thus, it is not surprising that these multifunctional cells have been implicated in the onset and progression of several neurodegenerative diseases. Astrocytes actively respond to neurotransmitters through changes in calcium ion levels. Astrocytes react to glutamate, GABA, acetylcholine, ATP, and endocannabinoids by releasing glutamate, GABA, D-serine, and ATP to influence activity of neighbouring neurons. As such, astrocytes maintain tight control of local ion and pH homeostasis, deliver glucose and provide metabolic substrates. Astrocytes also clear neuronal waste, including not only metabolic by products but also neurotransmitters released during synaptic transmission, which are sequestered through active uptake.

Keywords: Glial cell, synapse, neurotransmitter, neurohormone, white matter, gray matter, astrocytes, spinal cord.