Fig. 7. PDE inhibition restores cAMP signal but not vasoconstriction in AKAP5^−/− tissue.

a Time courses of the average ICUE3-PM traces (mean = solid line; SEM = shade) and b summary data of wild-type (WT; n = 22 cells/3 mice) and AKAP5^−/− (n = 12 cells/3 mice) arterial myocytes pretreated with the broad phosphodiesterase (PDE) inhibitor 3-isobutyl-1-methylxanthine (IBMX; 100 μM) in response to 20 mM D-glucose (D-glu) + NF546 and after application of forskolin. *P < 0.05 with two-tailed Mann–Whitney test. The single asterisks highlight significant differences between datasets in the absence of forskolin. The double asterisks indicate a statistical difference within the same experimental group in the absence and presence forskolin. All significant P values are <0.0001. c Exemplary diameter recordings and d summary myogenic tone data from WT (n = 6 arteries/4 mice) and AKAP5^−/− (n = 6 arteries/3 mice) cerebral arteries pretreated with IBMX (100 μM) before and after application of 20 mM D-glu and subsequent NF546. Scales = 10 μm (vertical) and 5 min (horizontal). Initial diameters shown on the traces left side. *P < 0.05 with Friedman one-way ANOVA with Dunn’s multiple comparisons. Statistical differences were compared between datasets within the same phenotype. P = 0.0281 for WT 10 mM D-glu + IBMX-20 mM D-glu + IBMX, and P = 0.0281 for WT 10 mM D-glu + IBMX-20 mM D-glu + NF546 + IBMX. Data represent mean ± SEM. e Proposed model for an AKAP5-dependent signaling module formed by P2Y₁₁/P2Y₁₁-like receptor, AC5, PKA and Ca_V1.2, which regulates L-type Ca²⁺ channel activity via Ca_V1.2 serine 1928 phosphorylation (pS¹⁹²⁸). Glucose-induced potentiation of L-type Ca²⁺ channel activity promotes vasoconstriction. The dotted black line is to reflect close association between AKAP5 and P2Y₁₁. PP2B = calcineurin. ATP = adenosine triphosphatase. The mechanisms of PDE regulation and nucleotide (NUC) release remain unclear as denoted by the red question mark symbols. Source data are provided as Source data file.