title: Nitric oxide decreases pacemaker activity in lymphatic vessels of guinea pig mesentery.
abstract: Intracellular microelectrode recordings were used to determine whether nitric oxide (NO), affects the pacemaker events that initiate vasomotion in lymphatic vessels of the guinea pig mesentery. This pacemaker activity is recorded as spontaneous transient depolarizations (STDs) and is likely to arise through synchronized Ca2+ release from intracellular stores. We show here that acetylcholine-induced endothelium-derived NO and exogenous NO released by sodium nitroprusside (SNP; 100 microM) and DEA-NONOate (500 microM) reduced the frequency and amplitude of STDs. This inhibition of STD frequency and amplitude was independent of the NO-induced hyperpolarization of the smooth muscle. The SNP-induced inhibition of STD frequency and amplitude was abolished during superfusion with the soluble guanylyl cyclase inhibitor ODQ (10 microM) and was diminished in the presence of cGMP and cAMP-dependent protein kinase inhibitors. The data are consistent with the hypothesis that NO inhibits vasomotion primarily by production of cGMP and activation of both cGMP- and cAMP-dependent protein kinases, which reduce the size and frequency of STDs, probably by acting on the underlying synchronized Ca2+ release from intracellular stores.
authors.affiliation: Department of Zoology and Animal Biology, University of Geneva, 1211 Geneva 4, Switzerland. vonderwe@ucalgary.ca
authors.forename: P Y
authors.initials: PY
authors.lastname: von der Weid
authors.forename: J
authors.initials: J
authors.lastname: Zhao
authors.forename: D F
authors.initials: DF
authors.lastname: Van Helden
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001683:Biological Clocks / Q000187:drug effects* / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D017869:Cyclic GMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005905:Glyburide / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008208:Lymphatic System / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008643:Mesentery / Q000187:drug effects* / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D014665:Vasodilator Agents; D005576:Colforsin; D009569:Nitric Oxide; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D017869:Cyclic GMP-Dependent Protein Kinases; D006152:Cyclic GMP; D000109:Acetylcholine; D005905:Glyburide; D002118:Calcium