ISDN2014_0323: GDP βs unsilences silent synapses in CA1 pyramidal cells by disinhibiting the protein kinase A activating pathway

2015 ◽  
Vol 47 (Part_A) ◽  
pp. 99-99
Author(s):  
M. Ouardouz
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Pyramidal Cells ◽  
Ca1 Pyramidal Cells ◽  
Silent Synapses ◽  
Kinase A

scholarly journals Kainate Receptor–Mediated Inhibition of Glutamate Release Involves Protein Kinase A in the Mouse Hippocampus

2006 ◽  
Vol 96 (4) ◽  
pp. 1829-1837 ◽  
Author(s):  
José V. Negrete-Díaz ◽  
Talvinder S. Sihra ◽  
José M. Delgado-García ◽  
Antonio Rodríguez-Moreno
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Mossy Fiber ◽  
Glutamate Release ◽  
Pyramidal Cells ◽  
Kainate Receptors ◽  
Mouse Hippocampus ◽  
Ca3 Pyramidal Cells ◽  
Kinase A ◽  
Stimulation Of

The mechanisms involved in the inhibition of glutamate release mediated by the activation of presynaptic kainate receptors (KARs) at the hippocampal mossy fiber–CA3 synapse are not well understood. We have observed a long-lasting inhibition of CA3 evoked excitatory postsynaptic currents (eEPSCs) after a brief application of kainate (KA) at concentrations ranging from 0.3 to 10 μM. The inhibition outlasted the change in holding current caused by the activation of ionotropic KARs in CA3 pyramidal cells, indicating that this action is not contingent on the opening of the receptor channels. The inhibition of the eEPSCs by KA was prevented by G protein and protein kinase A (PKA) inhibitors and was enhanced after stimulation of the adenylyl cyclase (AC) with forskolin. We conclude that KARs present at mossy fiber terminals mediate the inhibition of glutamate release through a metabotropic mechanism that involves the activation of an AC-second messenger cAMP-PKA signaling cascade.

Regulation of spontaneous and induced resumption of meiosis in mouse oocytes by different intracellular pathways

Reproduction ◽  
2000 ◽  
pp. 377-383 ◽  
Author(s):  
L Leonardsen ◽  
A Wiersma ◽  
M Baltsen ◽  
AG Byskov ◽  
CY Andersen
Keyword(s):  
Signal Transduction ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Mitogen Activated Protein Kinase ◽  
Meiotic Maturation ◽  
Mouse Oocytes ◽  
Mitogen Activated Protein ◽  
Dependent Signal ◽  
Kinase Pathway ◽  
Kinase A

The mitogen-activated protein kinase-dependent and the cAMP-protein kinase A-dependent signal transduction pathways were studied in cultured mouse oocytes during induced and spontaneous meiotic maturation. The role of the mitogen-activated protein kinase pathway was assessed using PD98059, which specifically inhibits mitogen-activated protein kinase 1 and 2 (that is, MEK1 and MEK2), which activates mitogen-activated protein kinase. The cAMP-dependent protein kinase was studied by treating oocytes with the protein kinase A inhibitor rp-cAMP. Inhibition of the mitogen-activated protein kinase pathway by PD98059 (25 micromol l(-1)) selectively inhibited the stimulatory effect on meiotic maturation by FSH and meiosis-activating sterol (that is, 4,4-dimethyl-5alpha-cholest-8,14, 24-triene-3beta-ol) in the presence of 4 mmol hypoxanthine l(-1), whereas spontaneous maturation in the absence of hypoxanthine was unaffected. This finding indicates that different signal transduction mechanisms are involved in induced and spontaneous maturation. The protein kinase A inhibitor rp-cAMP induced meiotic maturation in the presence of 4 mmol hypoxanthine l(-1), an effect that was additive to the maturation-promoting effect of FSH and meiosis-activating sterol, indicating that induced maturation also uses the cAMP-protein kinase A-dependent signal transduction pathway. In conclusion, induced and spontaneous maturation of mouse oocytes appear to use different signal transduction pathways.

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