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Pathway‐dependent modulation by P2‐purinoceptors in the mouse retina
Author(s) -
Kaneda Makoto,
Ishii Toshiyuki,
Hosoya Toshihiko
Publication year - 2008
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2008.06317.x
Subject(s) - purinergic receptor , cholinergic , amacrine cell , neuroscience , retina , microbiology and biotechnology , biology , adenosine , gabaergic , purinergic signalling , chemistry , inhibitory postsynaptic potential , endocrinology , adenosine receptor , biochemistry , receptor , agonist
Adenosine trisphosphate (ATP) activates purinoceptors and acts as a neurotransmitter in the nervous system. In the retina, we previously reported that the immunohistochemical distribution of the subset of P2‐purinoceptors differs between the ON and OFF pathways. Here, we investigated whether ATP activates P2‐purinoceptors and modulates the physiological function of the mouse retina. We also examined if signal processing by P2‐purinoceptors is pathway specific. Results showed that ATP activated both ON‐ and OFF‐cholinergic amacrine cells. However, responses in OFF‐cholinergic amacrine cells were greater than those in ON‐cholinergic amacrine cells. Pharmacological studies in OFF‐cholinergic amacrine cells showed that the response of OFF‐cholinergic amacrine cells is mediated P2X 2 ‐purinoceptors. Further, ATP increased γ‐aminobutyric acid (GABA)ergic inhibitory postsynaptic currents (IPSCs) in OFF‐ but not ON‐cholinergic amacrine cells. The increase in GABAergic IPSCs was mediated by P2‐purinoceptors. P2‐purinoceptor‐mediated signals suppressed OFF ganglion cells but activated ON ganglion cells. Our findings indicate that ATP physiologically modulates signal processing of the ON and OFF pathways in a pathway‐specific manner through P2‐purinoceptors.