title: NG-nitro-L-arginine methyl ester-induced potentiaton of the effect of aminophylline on rat diaphragm: the role of extracellular calcium.
abstract: The role of extracellular calcium in the interaction between intracellular cAMP and nitric oxide (NO)/cGMP on the contractility of rat diaphragm pretreated with cumulative concentrations of aminophylline (0.36 - 3.60 mM) was investigated. In a Ca2+-free medium, NG-nitro-L-arginine methyl ester (L-NAME) (1 and 3 mM) depressed tension developed (Td) and also aminophylline-induced potentiation of Td in a concentration-dependent manner. Verapamil (2.5 microM) or nicardipine (20 microM) significantly antagonized the potentiating effect of L-NAME on Td in a calcium-containing medium. However, in the presence of verapamil or nicardipine, L-NAME still produced statistically significant potentiation of the cumulative concentrations of aminophylline (0.36 - 3.60 mM), given in the second series.
authors.affiliation: Department of Clinical Pharmacology, Pharmacology and Toxicology, School of Medicine University of Belgrade, Belgrade, Serbia and Montenegro.
authors.forename: Radan
authors.initials: R
authors.lastname: Stojanovic
authors.forename: Zoran
authors.initials: Z
authors.lastname: Todorović
authors.forename: Zorica
authors.initials: Z
authors.lastname: Nesić
authors.forename: Sonja
authors.initials: S
authors.lastname: Vućković
authors.forename: Natasa
authors.initials: N
authors.lastname: Cerovac-Cosić
authors.forename: Milica
authors.initials: M
authors.lastname: Prostran
mesh_terms: D000628:Aminophylline / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000502:physiology*; D020746:Calcium Channels, L-Type / Q000502:physiology; D003964:Diaphragm; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D009569:Nitric Oxide / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D020746:Calcium Channels, L-Type; D000628:Aminophylline; D009569:Nitric Oxide; D002118:Calcium; D019331:NG-Nitroarginine Methyl Ester