title: Effect of aminophylline and verapamil upon diaphragmatic force generation in dogs.
abstract: The effects on the diaphragm of verapamil (VPM) and aminophylline (AMP) were studied in dogs during stimulation of phrenic nerves at the 5th cervical roots (5th-PS) or transvenously at the trunk (T-PS). Transdiaphragmatic pressure (Pdi)/frequency curves were constructed. Our findings were: 1) AMP increased Pdi at all stimulation frequencies (p less than 0.01) during 5th-PS but only at 10-30 Hz during T-PS; 2) in other dogs infusion of VPM (0.14 mg.kg-1.min-1) decreased Pdi at all frequencies (p less than 0.025) without change in diaphragmatic blood flow; 3) the effects of VPM were completely reverted by AMP; 4) after a large amount of AMP, infusion of VPM (0.21 mg.kg-1.min-1) decreased Pdi at all frequencies. Since these drugs have several mechanisms of action and do not show mutual blocking effect, different action sites are suggested.
authors.affiliation: Instituto de Investigaciones Médicas Alfredo Lanari, Universidad de Buenos Aires, Argentina.
authors.forename: E L
authors.initials: EL
authors.lastname: De Vito
authors.forename: A J
authors.initials: AJ
authors.lastname: Roncoroni
mesh_terms: D000628:Aminophylline / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D003964:Diaphragm / Q000098:blood supply / Q000187:drug effects* / Q000502:physiology; D004285:Dogs; D004347:Drug Interactions; D004558:Electric Stimulation / Q000379:methods; D006439:Hemodynamics / Q000187:drug effects; D007262:Infusions, Intravenous; D007275:Injections, Intravenous; D009119:Muscle Contraction / Q000187:drug effects; D010791:Phrenic Nerve; D011312:Pressure; D012039:Regional Blood Flow / Q000187:drug effects; D014700:Verapamil / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D000628:Aminophylline; D014700:Verapamil