Protein kinase C modulates microvascular permeability through nitric oxide synthase

Area of Science:

• Physiology
• Biochemistry
• Microcirculation Research

Background:

• Protein kinase C (PKC) plays a crucial role in cellular signal transduction pathways.
• Microvascular permeability to macromolecules is a tightly regulated process with implications for tissue homeostasis and disease.

Purpose of the Study:

• To investigate the role of nitric oxide (NO) in mediating the effects of PKC on microvascular permeability.
• To elucidate the signaling pathway through which PKC influences macromolecule transport across the microvasculature.

Main Methods:

• Topical stimulation of PKC using phorbol 12,13-dibutyrate (PDBu) in hamster cheek pouch microcirculation.
• Inhibition of nitric oxide synthase (NOS) activity using NG-monomethyl-L-arginine (L-NMMA).
• Quantification of macromolecule transport (fluorescein isothiocyanate-labeled dextran) using intravital fluorometry and digital image analysis.

Main Results:

• Phorbol 12,13-dibutyrate (PDBu) significantly increased macromolecule transport (IOI) in postcapillary venules.
• Pretreatment with L-NMMA markedly attenuated the PDBu-induced increase in macromolecule transport.
• The results indicate that PKC activation enhances microvascular permeability through NO-dependent mechanisms.

Conclusions:

• PKC-mediated modulation of microvascular permeability to macromolecules is dependent on nitric oxide (NO) production.
• This study identifies a key signaling pathway involving PKC and NO in regulating vascular barrier function.