scholarly journals Opioid and GABAB receptors differentially couple to an adenylyl cyclase/protein kinase A downstream effector after chronic morphine treatment

2014 ◽  
Vol 5 ◽  
Author(s):  
Elena E. Bagley
2019 ◽  
Vol 93 (8) ◽  
pp. 2279-2294
Author(s):  
Romina Belén Andermatten ◽  
Nadia Ciriaci ◽  
Virginia Soledad Schuck ◽  
Nicolás Di Siervi ◽  
María Valeria Razori ◽  
...  

2010 ◽  
Vol 299 (4) ◽  
pp. H1146-H1152 ◽  
Author(s):  
Meera Sridharan ◽  
Shaquria P. Adderley ◽  
Elizabeth A. Bowles ◽  
Terrance M. Egan ◽  
Alan H. Stephenson ◽  
...  

Erythrocytes release ATP in response to exposure to the physiological stimulus of lowered oxygen (O2) tension as well as pharmacological activation of the prostacyclin receptor (IPR). ATP release in response to these stimuli requires activation of adenylyl cyclase, accumulation of cAMP, and activation of protein kinase A. The mechanism by which ATP, a highly charged anion, exits the erythrocyte in response to lowered O2 tension or receptor-mediated IPR activation by iloprost is unknown. It was demonstrated previously that inhibiting pannexin 1 with carbenoxolone inhibits hypotonically induced ATP release from human erythrocytes. Here we demonstrate that three structurally dissimilar compounds known to inhibit pannexin 1 prevent ATP release in response to lowered O2 tension but not to iloprost-induced ATP release. These results suggest that pannexin 1 is the conduit for ATP release from erythrocytes in response to lowered O2 tension. However, the identity of the conduit for iloprost-induced ATP release remains unknown.


2006 ◽  
Vol 20 (9) ◽  
pp. 2231-2246 ◽  
Author(s):  
Arturo E. Gonzalez-Iglesias ◽  
Yonghua Jiang ◽  
Melanija Tomić ◽  
Karla Kretschmannova ◽  
Silvana A. Andric ◽  
...  

Abstract Pituitary lactotrophs in vitro fire extracellular Ca2+-dependent action potentials spontaneously through still unidentified pacemaking channels, and the associated voltage-gated Ca2+ influx (VGCI) is sufficient to maintain basal prolactin (PRL) secretion high and steady. Numerous plasma membrane channels have been characterized in these cells, but the mechanism underlying their pacemaking activity is still not known. Here we studied the relevance of cyclic nucleotide signaling pathways in control of pacemaking, VGCI, and PRL release. In mixed anterior pituitary cells, both VGCI-inhibitable and -insensitive adenylyl cyclase (AC) subtypes contributed to the basal cAMP production, and soluble guanylyl cyclase was exclusively responsible for basal cGMP production. Inhibition of basal AC activity, but not soluble guanylyl cyclase activity, reduced PRL release. In contrast, forskolin stimulated cAMP and cGMP production as well as pacemaking, VGCI, and PRL secretion. Elevation in cAMP and cGMP levels by inhibition of phosphodiesterase activity was also accompanied with increased PRL release. The AC inhibitors attenuated forskolin-stimulated cyclic nucleotide production, VGCI, and PRL release. The cell-permeable 8-bromo-cAMP stimulated firing of action potentials and PRL release and rescued hormone secretion in cells with inhibited ACs in an extracellular Ca2+-dependent manner, whereas 8-bromo-cGMP and 8-(4-chlorophenyltio)-2′-O-methyl-cAMP were ineffective. Protein kinase A inhibitors did not stop spontaneous and forskolin-stimulated pacemaking, VGCI, and PRL release. These results indicate that cAMP facilitates pacemaking, VGCI, and PRL release in lactotrophs predominantly in a protein kinase A- and Epac cAMP receptor-independent manner.


2021 ◽  
Vol 17 (8) ◽  
pp. e1009861
Author(s):  
Kyunghun Min ◽  
Thomas F. Jannace ◽  
Haoyu Si ◽  
Krishna R. Veeramah ◽  
John D. Haley ◽  
...  

Microbial pathogens grow in a wide range of different morphologies that provide distinct advantages for virulence. In the fungal pathogen Candida albicans, adenylyl cyclase (Cyr1) is thought to be a master regulator of the switch to invasive hyphal morphogenesis and biofilm formation. However, faster growing cyr1Δ/Δ pseudorevertant (PR) mutants were identified that form hyphae in the absence of cAMP. Isolation of additional PR mutants revealed that their improved growth was due to loss of one copy of BCY1, the negative regulatory subunit of protein kinase A (PKA) from the left arm of chromosome 2. Furthermore, hyphal morphogenesis was improved in some of PR mutants by multigenic haploinsufficiency resulting from loss of large regions of the left arm of chromosome 2, including global transcriptional regulators. Interestingly, hyphal-associated genes were also induced in a manner that was independent of cAMP. This indicates that basal protein kinase A activity is an important prerequisite to induce hyphae, but activation of adenylyl cyclase is not needed. Instead, phosphoproteomic analysis indicated that the Cdc28 cyclin-dependent kinase and the casein kinase 1 family member Yck2 play key roles in promoting polarized growth. In addition, integrating transcriptomic and proteomic data reveals hyphal stimuli induce increased production of key transcription factors that contribute to polarized morphogenesis.


2001 ◽  
Vol 85 (6) ◽  
pp. 2388-2397 ◽  
Author(s):  
Alexander Ivanov ◽  
Gary Aston-Jones

Noradrenergic neurons of the brain nucleus locus coeruleus (LC) become hyperactive during opiate withdrawal. It has been uncertain to what extent such hyperactivity reflects changes in intrinsic properties of these cells. The effects of withdrawal from chronic morphine on the activity of LC neurons were studied using intracellular recordings in rat brain slices. LC neurons in slices from chronically morphine-treated rats exhibited more than twice the frequency of spontaneous action potentials after naloxone compared with LC neurons from control rats. However, after naloxone treatment, the resting membrane potential (MP) of LC neurons from dependent rats was not significantly different from that in control rats. Neither resting MP nor spontaneous discharge rate (SDR) was altered by naloxone in LC neurons from control rats. Neither kynurenic acid nor a cocktail of glutamate and GABA antagonists (6-cyano-7-nitroquinoxalene-2,3-dione + 2-amino-5-phosphonopentanoic acid + bicuculline) blocked the hyperactivity of LC neurons precipitated by naloxone in slices from morphine-dependent rats. The effects of ouabain on MP and SDR were similar in LC neurons from control and morphine-dependent rats. These results indicate that an adaptive change in glutamatergic or GABAergic synaptic mechanisms or altered Na/K pump activity does not underlie the withdrawal-induced activation of LC neurons in vitro. Specific inhibitors of protein kinase A [Rp-cAMPS or N-(2-[p-bromocinnamylamino]ethyl)-5-isoquinolinesulfonamide (H-89)] partially suppressed the withdrawal hyperactivity of LC neurons, and activators of cAMP (forskolin) or protein kinase A (Sp-cAMPS) increased the discharge rate of LC neurons from control rats. These results suggest that upregulation of cAMP-dependent protein kinase A during chronic morphine treatment is involved in the withdrawal-induced hyperactivity of LC neurons.


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