Ca2+/calmodulin-dependent cyclic nucleotide phosphodiesterase in cGMP metabolism in rabbit parotid acinar cells

Abstract

Muscarinic cholinergic receptor activation provokes cGMP formation in parotid acinar cells. We investigated the involvement of Ca 2+ /calmodulin-dependent cyclic nucleotide phosphodiesterase (PDE1) in cGMP breakdown in rabbit parotid acinar cells. The muscarinic agonist carbachol stimulated cGMP formation in the cells. The carbachol-induced cGMP formation was enhanced in the presence of 8-methoxymethyl-3-isobutyl-1-methylxanthine (MM-IBMX), a PDE1 inhibitor. cGMP-PDE activity in rabbit parotid acinar cells was reduced by about 25% in the absence of Ca 2+ / calmodulin or in the presence of MM-IBMX. Ca 2+ /calmodulin-dependent cGMP-PDE in rabbit parotid acinar cells was purified using Calmodulin-Sepharose 4B and Mono Q ion-exchange column chromatography. Two dominant fractions with cGMP-PDE activity, referred to as the P-1 and P-2 fractions, were eluted from the Mono Q ion-exchange column. The Km values for cGMP of PDE in the P-1 and P-2 fractions were 0.82 μM and 0.40 μM, respectively, which were much lower than that for cAMP. The EC 50 for Ca 2+ and calmodulin of PDEs in the P-1 and P-2 fractions were 458 nM and 426 nM, respectively, and 32 nM and 137 nM, respectively. Protein bands that crossreacted with anti-PDE1A antibody were detected. These results suggest that Ca 2+

Pharmacological Evidence That Dictyostelium Differentiation-Inducing Factor 1 Promotes Glucose Uptake Partly via an Increase in Intracellular cAMP Content in Mouse 3T3-L1 Cells

“…Contrary to our expectation, the specific PDE1 inhibitor 8-MIBMX at up to 0.2 mM did not markedly affect glucose uptake in confluent 3T3-L1 cells (Figure 4), and the glucoseuptake-promoting effect of the broad-range PDE inhibitor IBMX at up to 0.4 mM (Figure 5) was very weak or absent. Although the membrane permeability of 8-MIBMX and IBMX in confluent 3T3-L1 cells is not known, both inhibitors are effective at 0.1-0.2 mM in other in vitro cell culture systems [49,50]. Thus, our results suggest that PDEs, including PDE1, may not be involved in DIF-1-induced glucose uptake.…”

The cAMP-phosphodiesterase 4 (PDE4) controls β-adrenoceptor- and CFTR-dependent saliva secretion in mice

“…4F), this does not principally exclude a potential role for PDE4 in regulating salivation induced by other secretagogues that act via activation of G q -coupled receptors and intracellular calcium signaling, given the multitude of cAMP-signaling events known to regulate receptor-and/or ion channel functions. Furthermore, and in light of the observation that muscarinic stimulation has been shown to increase cGMP signaling in rabbit parotid acinar cells 45 , the role of PDE families other than PDE3 and PDE4 (Fig. 1C) as well as the role of cGMP signaling in the regulation of saliva secretion remain to be explored.…”

Increased particulate phosphodiesterase 4 in the prefrontal cortex supports 5-HT4 receptor-induced improvement of object recognition memory in the rat

“…Differences between total and selective inhibitorinsensitive PDE activities were considered as the corresponding PDE activities. Moreover, determination of PDE1 activity was performed in the presence of 10 nM calmodulin and 0.2 mM CaCl 2 (Sairenji et al 2006).…”