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Mechanism of nitric oxide action on inhibitory GABAergic signaling within the nucleus tractus solitarii
Author(s) -
Wang Sheng,
Teschemacher Anja G.,
Paton Julian F. R.,
Kasparov Sergey
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.05-5547fje
Subject(s) - gabaergic , inhibitory postsynaptic potential , long term potentiation , neurotransmission , chemistry , nitric oxide , ryanodine receptor , postsynaptic potential , glutamate receptor , microbiology and biotechnology , retrograde signaling , glutamatergic , nucleus , neuroscience , biophysics , biology , intracellular , biochemistry , signal transduction , receptor , organic chemistry
The cellular mechanisms mediating nitric oxide (NO) modulation of the inhibitory transmission in the nucleus tractus solitarii (NTS) remain unclear, even though this could be extremely important for various physiological and pathological processes. Specifically, in the NTS NO‐evoked glutamate and γ‐aminobutyric acid (GABA) release might contribute to pathological hypertension. In cultured rat brainstem slices, NTS GABAergic neurons were targeted using an adenoviral vector to express enhanced green fluorescent protein and studied with a combination of patch clamp and confocal microscopy. Low nanomolar concentrations of NO increased intracellular Ca 2+ concentration ([Ca 2+ ] i ) in somata, dendrites, and putative axons of GABAergic neurons, with axons being the most sensitive compartment. This effect was cGMP mediated and not related to depolarization or indirect presynaptic effects on glutamatergic transmission. Blockade of the cyclic adenosine diphosphate ribose (cADPR)/ryanodine‐sensitive stores but not the inositol triphosphate‐sensitive stores, inhibited NO effect. Since cADPR/ryanodine‐sensitive stores are implicated in the Ca 2+ ‐induced Ca 2+ release, NO can be expected to potentiate GABA release. In support of this notion, a cADPR antagonist abolished the NO‐induced potentiation of GABAergic inhibitory postsynaptic potentials in the NTS. Thus, the NO‐cGMP‐cADPR‐Ca 2+ pathway, previously described in sea urchin eggs, also operates in mammalian GABAergic neurons. Potentiation of GABA release by NO may have implications for numerous brain functions.—Wang, S., Teschemacher, A. G., Paton, J. F. R., Kasparov, S. Mechanism of nitric oxide on inhibitory GABAergic signaling within the nucleus tractus solitarii. FASEB J. 20, E821–E831 (2006)