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AMPA receptor activation and phosphatase inhibition affect neonatal rat respiratory rhythm generation
Author(s) -
Ge Qing,
Feldman Jack L.
Publication year - 1998
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.1998.255bo.x
Subject(s) - ampa receptor , tetrodotoxin , phosphatase , biology , endocrinology , medicine , kainate receptor , chemistry , glutamate receptor , neuroscience , receptor , microbiology and biotechnology , biochemistry , phosphorylation
1 We investigated the role of α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionate (AMPA) receptors and their regulation in affecting respiratory‐related neurones in a neonatal rat medullary slice that spontaneously generates respiratory‐related rhythm and motor output in the hypoglossal (XII) nerve. 2 Bath application of the AMPA receptor antagonist 1‐(4‐aminophenyl)‐4‐methyl‐7,8‐methylenedioxy‐5H‐2,3‐benzodiazepine (GYKI) completely blocked XII nerve activity, as well as respiratory‐related synaptic drives in neurones within the preBötzinger Complex (preBötC), site of rhythm generation in the slice. 3 Local application of GYKI to the preBötC blocked respiratory rhythm. Local application of AMPA to the preBötC increased rhythm frequency and depolarized respiratory‐related neurones. 4 In the presence of tetrodotoxin (TTX), GYKI completely blocked the inward current induced by local application of AMPA, but not that induced by kainate. 5 Local application of okadaic acid, a membrane‐permeable inhibitor of phosphatase 1 and 2A, to the preBötC increased the frequency of respiratory motor discharge. 6 Intracellular application of microcystin, a membrane‐impermeable inhibitor of phosphatase 1 and 2A, enhanced endogenous inspiratory drive and exogenous AMPA‐induced current (in the presence of TTX) in preBötC inspiratory neurones. Both the enhanced inspiratory drive and the increased AMPA‐induced current were completely blocked by GYKI. 7 We suggest that AMPA receptor activation and AMPA receptor modulation by phosphorylation are crucial for the rhythm generation within the preBötC.