We demonstrate spatially resolved probing and imaging of pH in live cells by mobile and biocompatible nanosensors using surface-enhanced Raman scattering (SERS) of 4-mercaptobenzoic acid (pMBA) on gold nanoaggregates. Moreover, we also show that this concept of pH nanosensors can be extended to two-photon excitation by using surface-enhanced hyper-Raman scattering (SEHRS). In addition to the advantages of two-photon excitation, the SEHRS sensor enables measurements over a wide pH range without the use of multiple probes.

The inhibition of voltage-dependent Ca2+ channels in secretory cells by plasma membrane receptors is mediated by pertussis toxin-sensitive G proteins. Multiple forms of G proteins have been described, differing principally in their alpha subunits, but it has not been possible to establish which G-protein subtype mediates inhibition by a specific receptor. By intranuclear injection of antisense oligonucleotides into rat pituitary GH3 cells, the essential role of the Go-type G proteins in Ca(2+)-channel inhibition is established: the subtypes Go1 and Go2 mediate inhibition through the muscarinic and somatostatin receptors, respectively.

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Abstract-Nuclear factor-B (NF-B) regulates many genes involved in vascular physiopathology. We have previously observed in vivo NF-B activation in injured vessels that diminished by angiotensin-converting enzyme inhibition. In the present work, we investigated the effect of angiotensin II (Ang II) on NF-B activity in rat vascular smooth muscle cells, evaluating the molecular mechanisms and the specific receptor subtype involved. Ang II increased NF-B DNA binding (5-fold, 10 Ϫ9 mol/L at 1 hour; electrophoretic mobility shift assay), nuclear translocation of p50/p65 subunits, and cytosolic inhibitor B␣ (IB␣) degradation. Ang II elicited NF-B-mediated transcription (transfection of a reporter gene) and expression of NF-B-related genes (monocyte chemoattractant protein-1 and angiotensinogen). AT 1 (DUP753) and AT 2 (PD123319 and CGP42112) receptor antagonists inhibited Ang II-induced NF-B DNA binding in a dose-dependent manner (Ϸ85% for each one; 10 Ϫ5 mol/L at 1 hour). The AT 2 agonist p-aminophenylalanine 6 -Ang II augmented NF-B binding (4.6-fold, 10 Ϫ9 mol/L at 1 hour), p65 nuclear levels, and transcription of an NF-B reporter gene. AT 1 antagonist markedly inhibited NF-B-mediated transcription and gene expression. Some differences between AT 1 /AT 2 intracellular signals were found. Antioxidants and ceramide inhibitors, but not protein kinase C inhibitors, diminished NF-B activation elicited by both Ang II and the AT 2 agonist, while tyrosine kinase inhibitors only decreased Ang II-induced NF-B activity. Our results demonstrate that Ang II activates NF-B via AT 1 and AT 2 , although NF-B-mediated transcription occurred mainly through AT 1 . Both receptors share some signaling pathways (oxygen radicals and ceramide); however, tyrosine kinases only participate in AT 1 /NF-B responses. These data provide novel insights into Ang II actions, suggesting a potential implication of the AT 2 in the pathobiology of vascular cells.