title: 8Br-cGMP mediates relaxation of tracheal smooth muscle through PKA.
abstract: In this study, guinea pig tracheal smooth muscle pre-contracted with histamine was relaxed by the addition of 100microM 8Br-cGMP, a non-hydrolyzable and cell-permeable analog for cGMP. This effect was not sensitive to cGMP-dependent protein kinase (PKG) inhibitors, whereas it was partially blocked by cAMP-dependent protein kinase (PKA) inhibitors. The relaxation observed was also reverted up to 50+/-8.5% by iberiotoxin, a selective inhibitor of large conductance, calcium-activated potassium channels (BK(Ca)). Our results indicate that there exists a crosstalk mechanism between cAMP and cGMP signaling pathways which lead to relaxation of guinea pig tracheal smooth muscle and also that BK(Ca) channels are involved to a certain extent in this phenomenon.
authors.affiliation: Departamento de Fisiología y Farmacología, Facultad de Medicina, Universidad Autónoma de San Luis Potosi, S.L.P. 78210, San Luis Potosí, Mexico.
authors.forename: Paola
authors.initials: P
authors.lastname: Algara-Suárez
authors.forename: Ricardo
authors.initials: R
authors.lastname: Espinosa-Tanguma
mesh_terms: D000818:Animals; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism / Q000502:physiology*; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000378:metabolism / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006168:Guinea Pigs; D006632:Histamine / Q000378:metabolism; D008297:Male; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000201:enzymology*; D010455:Peptides / Q000494:pharmacology; D015398:Signal Transduction; D014118:Toxins, Biological; D014132:Trachea / Q000166:cytology* / Q000187:drug effects
chemical_list: D004791:Enzyme Inhibitors; D010455:Peptides; D014118:Toxins, Biological; C016276:8-bromocyclic GMP; C064719:iberiotoxin; D006632:Histamine; D017868:Cyclic AMP-Dependent Protein Kinases; D006152:Cyclic GMP