Vesicular release mechanisms in astrocytic signalling.
Astrocytes play an important role in chemical signalling, acting as receptive as well as secretory elements. They can express receptors for essentially all classical neurotransmitter substances and for a large variety of peptides. Recent evidence indicates that astrocytes are involved in the information processing within the nervous system. Astrocytes respond to various neurotransmitters with elevations in intracellular calcium which can either be long-duration Ca(2+) spikes or oscillations in Ca(2+) levels. Astrocytic excitation can be propagated to adjacent astrocytes in the form of Ca(2+) waves. Due to their intimate spatial relationship with synaptic contacts, astrocytes can directly respond to synaptically released messengers and communicate, via signalling substances, with neurons in a reciprocal manner. Cultured astrocytes and astroglioma cells express synaptic vesicle proteins and members of the synaptic SNARE complex. Astrocytes can release a variety of messenger substances via receptor-mediated mechanisms implicating their potential for regulated exocytosis and the participation of proteins of the SNARE complex.
Volknandt
Walter
W
Department of Neurochemistry, Zoological Institute, Biocenter, J.W. Goethe-University, Marie-Curie Street 9, D-60439, Frankfurt am Main, Germany. volknandt@zoology.uni-frankfurt.de
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001253:Astrocytes / Q000378:metabolism / Q000502:physiology*; D020013:Calcium Signaling / Q000502:physiology; D002450:Cell Communication / Q000502:physiology; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D009474:Neurons / Q000502:physiology; D018377:Neurotransmitter Agents / Q000378:metabolism; D050600:SNARE Proteins; D015398:Signal Transduction / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology; D013572:Synaptic Vesicles / Q000378:metabolism*; D033921:Vesicular Transport Proteins
D008565:Membrane Proteins; D018377:Neurotransmitter Agents; D050600:SNARE Proteins; D033921:Vesicular Transport Proteins; D000255:Adenosine Triphosphate