Activation of metabotropic glutamate receptors increase the frequency of spontaneous GABAergic currents through protein kinase A in neonatal rat hippocampal neurons

1995 ◽  
Vol 74 (3) ◽  
pp. 1118-1122 ◽  
Author(s):  
M. Sciancalepore ◽  
F. Stratta ◽  
N. D. Fisher ◽  
E. Cherubini
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Frequency Ratio ◽  
Hippocampal Neurons ◽  
Neonatal Rat ◽  
Synaptic Currents ◽  
Mean Frequency ◽  
Metabotropic Glutamate ◽  
The Mean ◽  
Kinase A

1. The tight-seal whole cell recording technique was used to study the effects of the metabotropic glutamate receptor (mGluR) agonist, trans-1-aminocyclopentane-1,3-dicarboxylic acid (t-ACPD) on spontaneous gamma-aminobutyric acid (GABA)-mediated synaptic currents in neonatal rat CA1 hippocampal neurons in slices obtained from postnatal (P) days P6-P12. 2. Bath application of t-ACPD (3-30 microM), in the presence of kynurenic acid, induced a concentration-dependent increase in frequency but not in amplitude of spontaneous GABAergic currents. The mean frequency ratio (t-ACPD 10 microM over control) was 2.6 +/- 1 (mean +/- SD), whereas the mean amplitude ratio was 1.1 +/- 0.3. 3. The effect of t-ACPD was partially antagonized by the mGluR antagonist (RS)-alpha-methyl-4-carboxyphenylglycine (MCPG, 1 mM). 4. t-ACPD (10-30 microM) did not modify the frequency of miniature GABAergic synaptic currents recorded in tetrodotoxin (the mean frequency ratio of t-ACPD over control was 0.7 +/- 0.3). 5. Forskolin (30 microM), but not its analogue 1,9 dideoxyforskolin (30 microM), mimicked the effect of t-ACPD. Similar effects were obtained with 3-isobutyl-1-methylxanthine (IBMX, 200 microM). 6. The potentiating effect of t-ACPD on spontaneous GABAergic currents was prevented by Rp-cAMPS (30 microM), a specific antagonist of protein kinase A. This suggests that mGluRs localized at the soma-dendritic level of GABAergic interneurons and positively coupled to cyclic AMP may modulate GABA release during a critical period of postnatal development.

scholarly journals Chronic opioids regulate KATP channel subunit Kir6.2 and carbonic anhydrase I and II expression in rat adrenal chromaffin cells via HIF-2α and protein kinase A

2014 ◽  
Vol 307 (3) ◽  
pp. C266-C277 ◽  
Author(s):  
Shaima Salman ◽  
Alison C. Holloway ◽  
Colin A. Nurse
Keyword(s):  
Protein Kinase ◽  
Carbonic Anhydrase ◽  
Protein Kinase A ◽  
Chromaffin Cells ◽  
Time Course ◽  
Molecular Mechanisms ◽  
Hypoxia Inducible Factor ◽  
Neonatal Rat ◽  
Pcr Analysis ◽  
Kinase A

At birth, asphyxial stressors such as hypoxia and hypercapnia are important physiological stimuli for adrenal catecholamine release that is critical for the proper transition to extrauterine life. We recently showed that chronic opioids blunt chemosensitivity of neonatal rat adrenomedullary chromaffin cells (AMCs) to hypoxia and hypercapnia. This blunting was attributable to increased ATP-sensitive K+ (KATP) channel and decreased carbonic anhydrase (CA) I and II expression, respectively, and involved μ- and δ-opioid receptor signaling pathways. To address underlying molecular mechanisms, we first exposed an O2- and CO2-sensitive, immortalized rat chromaffin cell line (MAH cells) to combined μ {[d-Arg2,Ly4]dermorphin-(1–4)-amide}- and δ ([d-Pen2,5,P-Cl-Phe4]enkephalin)-opioid agonists (2 μM) for ∼7 days. Western blot and quantitative real-time PCR analysis revealed that chronic opioids increased KATP channel subunit Kir6.2 and decreased CAII expression; both effects were blocked by naloxone and were absent in hypoxia-inducible factor (HIF)-2α-deficient MAH cells. Chronic opioids also stimulated HIF-2α accumulation along a time course similar to Kir6.2. Chromatin immunoprecipitation assays on opioid-treated cells revealed the binding of HIF-2α to a hypoxia response element in the promoter region of the Kir6.2 gene. The opioid-induced regulation of Kir6.2 and CAII was dependent on protein kinase A, but not protein kinase C or calmodulin kinase, activity. Interestingly, a similar pattern of HIF-2α, Kir6.2, and CAII regulation (including downregulation of CAI) was replicated in chromaffin tissue obtained from rat pups born to dams exposed to morphine throughout gestation. Collectively, these data reveal novel mechanisms by which chronic opioids blunt asphyxial chemosensitivity in AMCs, thereby contributing to abnormal arousal responses in the offspring of opiate-addicted mothers.

Protein kinase A activation is required for IL-1-induced nitric oxide production by cardiac myocytes

1996 ◽  
Vol 271 (1) ◽  
pp. C429-C434 ◽  
Author(s):  
C. V. Oddis ◽  
R. L. Simmons ◽  
B. G. Hattler ◽  
M. S. Finkel
Keyword(s):  
Nitric Oxide ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Cardiac Myocytes ◽  
Interleukin 1 ◽  
Neonatal Rat ◽  
Inos Mrna ◽  
No Production ◽  
Neonatal Rat Cardiac Myocytes ◽  
Kinase A

We have previously reported that interleukin-1 beta (IL-1) alone induced the transcription of inducible nitric oxide synthase (iNOS) mRNA and nitric oxide (NO) production by isolated neonatal rat cardiac myocytes (CM). The present studies were undertaken to explore the signal transduction pathways involved in IL-1-induced NO production by CM. The addition of IL-1 to CM resulted in a peak rise in both adenosine 3',5'-cyclic monophosphate (cAMP) and protein kinase A (PKA) activities by 10 min followed by rapid declines and return to basal levels within 60 min. The PKA inhibitor KT-5720 completely blocked NO-2 production by IL-1-stimulated CM (P < 0.01; n = 12). The protein kinase C (PKC) inhibitor, calphostin C, had no effect on NO2- production by IL-1 stimulated CM [P = not significant (NS); n = 12]. The addition of PKA+cAMP to cytosols derived from IL-1-treated CM did not directly enhance iNOS enzyme activity (P = NS; n = 3). CM treated with IL-1 alone stained positively for iNOS protein by immunohistochemistry. iNOS staining was absent in CM treated with IL-1+KT-5720. KT-5720 resulted in an earlier disappearance of iNOS mRNA from IL-1-treated CM, as detected by semiquantitative reverse transcriptase-polymerase chain reaction. We report for the first time that PKA (but not PKC) activation is required for IL-1-induced NO production by CM.

scholarly journals Protein kinase A directly phosphorylates metabotropic glutamate receptor 5 to modulate its function

2015 ◽  
Vol 132 (6) ◽  
pp. 677-686 ◽  
Author(s):  
Ken Uematsu ◽  
Myriam Heiman ◽  
Marina Zelenina ◽  
Júlio Padovan ◽  
Brian T. Chait ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Glutamate Receptor ◽  
Metabotropic Glutamate Receptor ◽  
Metabotropic Glutamate Receptor 5 ◽  
Metabotropic Glutamate ◽  
Kinase A

scholarly journals AKAP79 enables calcineurin to directly suppress protein kinase A activity

2021 ◽  
Author(s):  
Timothy W. Church ◽  
Parul Tewatia ◽  
Saad Hannan ◽  
João Antunes ◽  
Olivia Eriksson ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Hippocampal Neurons ◽  
Second Messengers ◽  
Capture Rate ◽  
Receptor Protein ◽  
Regulatory Subunits ◽  
Cellular Processes ◽  
Order Of Magnitude ◽  
Kinase A

Interplay between the second messengers cAMP and Ca2+ is a hallmark of dynamic cellular processes. A common motif is the opposition of the Ca2+-sensitive phosphatase calcineurin and the major cAMP receptor, protein kinase A (PKA). Calcineurin dephosphorylates sites primed by PKA to bring about changes including synaptic long-term depression (LTD). AKAP79 supports signaling of this type by anchoring PKA and calcineurin in tandem. In this study, we discovered that AKAP79 increases the rate of calcineurin dephosphorylation of type II PKA regulatory subunits by an order of magnitude. Fluorescent PKA activity reporter assays, supported by kinetic modeling, show how AKAP79-enhanced calcineurin activity enables suppression of PKA without altering cAMP levels by increasing PKA catalytic subunit capture rate. Experiments with hippocampal neurons indicate that this mechanism contributes towards LTD. This non-canonical mode of PKA regulation may underlie many other cellular processes.

Abstract 072: Protein Kinase A prevents cardiomyocyte hypertrophy through abhydrolase domain containing 5 (ABHD5)-mediated proteolysis of Histone deacetylase 4(HDAC4)

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Zegeye H Jebessa ◽  
Barbara Worst ◽  
Hugo A Katus ◽  
Johannes Backs
Keyword(s):  
Lipid Metabolism ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Serine Protease ◽  
Histone Deacetylase ◽  
Neonatal Rat ◽  
Cardiomyocyte Hypertrophy ◽  
Histone Deacetylase 4 ◽  
The Individual ◽  
Kinase A

Histone deacetylase 4 (HDAC4) regulates numerous gene expression programs through its signal-dependent repression of the transcription factor myocyte enhancer factor 2 (MEF2). Calcium/calmodulin-dependent protein kinase II (CaMKII) signaling promotes pathological cardiac remodeling by phosphorylating HDAC4, with consequent stimulation of MEF2 activity. Recently, we described a novel mechanism whereby protein kinase A (PKA) overcomes CaMKII-mediated activation of MEF2 by regulated proteolysis of HDAC4. PKA induces the generation of an N-terminal HDAC4 cleavage product (HDAC4-NT). HDAC4-NT inhibits MEF2 activity, thereby antagonizing the pro-hypertrophic actions of CaMKII signaling. However, the individual protease mediating HDAC4 proteolysis remains unknown. Using a number of group specific chemical protease inhibitors, we found that the PKA-dependent HDAC4 protease belongs to the family of serine proteases. To further identify the individual serine protease, we screened a human serine protease siRNA library and found abhydrolase domain containing 5 (ABHD5) to be required for PKA-induced HDAC4 proteolysis. The screening result was validated using three different siRNAs. Remarkably, forced adenoviral expression of ABHD5 led to robust production of HDAC4-NT in isolated neonatal rat ventricular myocytes (NRVMs) even in the absence of PKA. Furthermore, adenoviral expression of ABHD5 in NRVMs inhibited MEF2 transcriptional activity and attenuated cardiomyocyte hypertrophy. Interestingly, ABHD5 was initially described to be involved in lipid metabolism. Taken together, we show that ABHD5 is required for PKA-dependent HDAC4 proteolysis and sufficient for HDAC4-NT production as well as inhibition of cardiomyocyte hypertrophy. These data imply a so far unknown link between lipid metabolism and epigenetic regulation of cardioprotection.

scholarly journals AKAP79 enables calcineurin to directly suppress protein kinase A activity

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Timothy W Church ◽  
Parul Tewatia ◽  
Saad Hannan ◽  
João Antunes ◽  
Olivia Eriksson ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Hippocampal Neurons ◽  
Second Messengers ◽  
Capture Rate ◽  
Receptor Protein ◽  
Regulatory Subunits ◽  
Cellular Processes ◽  
Order Of Magnitude ◽  
Kinase A

Interplay between the second messengers cAMP and Ca2+ is a hallmark of dynamic cellular processes. A common motif is the opposition of the Ca2+-sensitive phosphatase calcineurin and the major cAMP receptor, protein kinase A (PKA). Calcineurin dephosphorylates sites primed by PKA to bring about changes including synaptic long-term depression (LTD). AKAP79 supports signaling of this type by anchoring PKA and calcineurin in tandem. In this study, we discovered that AKAP79 increases the rate of calcineurin dephosphorylation of type II PKA regulatory subunits by an order of magnitude. Fluorescent PKA activity reporter assays, supported by kinetic modeling, show how AKAP79-enhanced calcineurin activity enables suppression of PKA without altering cAMP levels by increasing PKA catalytic subunit capture rate. Experiments with hippocampal neurons indicate that this mechanism contributes towards LTD. This non-canonical mode of PKA regulation may underlie many other cellular processes.

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