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Title: Presynaptic signalling mediated by mono- and dinucleotides in the central nervous system
Authors: Miras-Portugal, M. Teresa
Díaz-Hernández, Miguel
Gomez-Villafuerte, Rosa
Gualix, Javier
Castro López-Tarruella, Enrique 
Pintor, Jesús
UNESCO Clasification: 32 Ciencias médicas
Keywords: Nucleotide
Diadenosine polyphosphates
Dinucleotide receptor
Diinosine polyphosphates
Issue Date: 2000
Publisher: 0165-1838
Journal: Journal of the Autonomic Nervous System 
Abstract: Synaptosomal preparations from rat midbrain exhibit specific responses to both ATP and Ap5A, which elicit a Ca2+ entrance to the presynaptic terminals. Studies of isolated single terminals showed that not all the terminals contain ionotropic receptors for nucleotides, in fact only 46% of them do. Of these, 12% responded only to the dinucleotide Ap5A, and 20% to the mononucleotide ATP. At the presynaptic level, diinosine pentaphosphate, Ip5I, is a good tool to specifically block dinucleotide responses, which are inhibited at low nM concentration, versus the high μM concentrations required to block ATP responses. There is evidence for a presynaptic control of mononucleotide and dinucleotide responses, mediated by metabotropic and ionotropic receptors. Stimulation of adenosine A1 receptors increases the affinity of dinucleotide receptors by five orders of magnitude, from 30 μM to 680 pM for control and in the presence of A1 agonist, respectively.
ISSN: 0165-1838
DOI: 10.1016/S0165-1838(00)00138-7
Source: Journal of the Autonomic Nervous System [ISSN 0165-1838], v. 81, p. 195-199
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