PKA pathway

H2 receptor stimulation in mammalian cerebral cortex and hippocampus produces excitation by inhibition of Ca2+-activated K+ conductances (Table 14-2). This effect resembles that produced by activation of [3-adrenergic receptors in these areas and both are mediated by increases in the cAMP-PKA pathway [1], H2 receptor activation also facilitates depolarization by enhancing the IH current,... 

Dopamine receptor signaling through the PKA pathway mediates many effects of psychomotor stimulants 918... 

In C albicans, mutations that block cAMP/PKA pathway suppress or delay the apoptotic response to H2O2 and amphotericin B. By contrast, mutations that result in constitutive activation of the RAS pathway accelerate entry into the apoptotic pathway Apoptosis and quorum sensing in filamentous fungi are phenomena associated with stress responses, a recurring motif in morphogenesis and secondary metabolism. The treatment of Colletotrichum trifolii with proline, a known stress relief chemical, suppressed apoptosis associated with Ras as well as apoptosis associated with a variety of other stresses. 

Agonists at group II and group III mGlu receptors may be useful in downregulating the enhanced responses of nociceptive neurons during neuronal sensitization which involves the cAMP - PKA pathway... 

Mooney RD, Shi MY, Rhoades RW (1994) Modulation of retinotectal transmission by presynaptic 5-HTib receptors in the superior colliculus of the adult hamster. J Neurophysiol 72 3-13 Moreno-Delgado D, Torrent A, Gomez-Ramirez J, de Esch I, Blanco I, Ortiz J (2006) Constitutive activity of H3 autoreceptors modulates histamine synthesis in rat brain through the cAMP/PKA pathway. Neuropharmacology 51 517-23... 

Fig. 2 Mechanisms involved in presynaptic facilitation through A2 adenosine receptors. A2A and A2B adenosine receptors (A2aAR, A2B AR), by coupling to Gs, activate adenylate cyclase and protein kinase A (PKA). This may (1) influence SNARE proteins or (2) enhance calcium currents through P-type voltage-sensitive calcium channels (P-VSCC). A2aAR may also couple to Gq, leading to activation of a protein kinase C (PKC) pathway. This may (3) enhance calcium currents through N-VSCC, (4) influence SNARE proteins, (5) promote the PKA pathways or (6) remove an ongoing Gj/0 mediated inhibition of release.

We have already seen a contingency in functioning of cAMP and PKA in previous sections. During glial inflammation, expression of several cytokines and iNOS is dependent on the cAMP-PKA pathway. While expression of cytokines like IL-1 p is completely dependent on PKA, expression of pro-inflammatory moieties, like iNOS, are partially dependent on this enzyme (Woo et al., 2004). Despite its partial role, activation of this... 

Cannabinoids have been shown to induce cell cycle arrest in breast carcinoma (De Petrocellis et al. 1998), prostate carcinoma (Melck et al. 2000) and thyroid epithelioma cells (Bifulco et al. 2001). In breast carcinoma cells this has been ascribed to the inhibition of adenylyl cyclase and the cAMP/protein kinase A (PKA) pathway (Table 1). PKA phosphorylates and inhibits Raf-1, so cannabinoids prevent the inhibition of Raf-1 and induce prolonged activation of the Raf-l/MEK/ERK signalling cascade (Melck et al 1999). Cannabinoid-induced inhibition of thyroid epithelioma cell proliferation has been attributed to the induction of the cyclin-dependent kinase inhibitor p27 P (Portella et al. 2003). 

HSP12 Plasma membrane localized protein that protects membranes from desiccation induced by heat shock, oxidative stress, osmostress, stationary phase entry, glucose depletion, oleate and alcohol regulated by the HOG and Ras-Pka pathways... 

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