What question did this study set out to answer?

To determine how PKA and PKG regulate adenylyl cyclase types V/VI, PDE3A, and PDE4 activities to modulate cyclic AMP signaling and contraction in smooth muscle cells.

March 1, 2002AJP Cell Physiology

PKA-dependent activation of PDE3A and PDE4 and inhibition of adenylyl cyclase V/VI in smooth muscle

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Population

Gastric smooth muscle cells

Design

Preclinical

Authors

KMKarnam S. MurthyVirginia Commonwealth University HZHuiping ZhouXuzhou Medical College GMGabriel M. MakhloufTufts University

Discussion

Member takes

Implication

Requires human validation before any clinical consideration; leaves open targeted modulation of PDE-AC feedback in vascular disease.

Key Points

To determine how PKA and PKG regulate adenylyl cyclase types V/VI, PDE3A, and PDE4 activities to modulate cyclic AMP signaling and contraction in smooth muscle cells.
Examined PDE3 isoform expression and baseline PDE3 versus PDE4 activity ratios in isolated gastric smooth muscle cells using RT-PCR and Western blotting.
Treated smooth muscle cells with pharmacological stimulators and inhibitors of PKA and PKG to monitor enzyme phosphorylation, catalytic activity, IP3-induced Ca2+ release, and contraction.
PKA activation via forskolin, isoproterenol, or specific cyclic nucleotide analogues stimulated PDE3A phosphorylation and elevated both PDE3A and PDE4 activities, which was blocked by PKA inhibitors (PKI, H-89) but not PKG inhibitors.
Forskolin induced adenylyl cyclase phosphorylation alongside catalytic activation; PKI abolished this phosphorylation while further boosting enzyme activity, indicating inhibitory feedback by PKA.
cGMP generation triggered by sodium nitroprusside inhibited PDE3 activity to elevate cAMP levels, while dual inhibition of PDE3 and PDE4 additively suppressed IP3-dependent Ca2+ release and muscle contraction.

Structured PICO

Population

Gastric smooth muscle cells

Intervention

Pharmacological modulation using forskolin, isoproterenol, PKA activators/inhibitors, PKG inhibitors, and sodium nitroprusside

Outcome

Phosphorylation and activity of PDE3A, PDE4, and adenylyl cyclase type V/VI, and cAMP levelssurrogate

This preclinical study elucidates the complex feedback regulation of cAMP levels in smooth muscle cells through PKA-dependent phosphorylation of phosphodiesterases and adenylyl cyclase.

Cite This Study

Murthy et al. (2002) studied this question.

synapsesocial.com/papers/6a834777dfd29b4838ca9c81 https://doi.org/10.1152/ajpcell.00373.2001

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PKA-dependent activation of PDE3A and PDE4 and inhibition of adenylyl cyclase V/VI in smooth muscle

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

PKA-dependent activation of PDE3A and PDE4 and inhibition of adenylyl cyclase V/VI in smooth muscle

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider