title: The influence of propofol, remifentanil and lidocaine on the tone of human bronchial smooth muscle.
abstract: BACKGROUND
  Bronchoscopy is generally a safe procedure, but the induction of anaesthesia can induce bronchospasm. Consequently we investigated the influence of propofol, remifentanil and lidocaine on the tone of the human bronchial smooth muscle.
  
  
  METHODS
  The influence of propofol, remifentanil and lidocaine on the contractile response of human bronchial smooth muscle to electrical field stimulation (EFS) has been evaluated. The role of capsaicin-sensitive sensory nerves and of inducible nitric oxide synthase has also been assessed. Furthermore, the interaction between these three dugs has been measured by Bliss Independence (BI) theory. Statistical significance (P < 0.05) was assessed by Student's t test or ANOVA.
  
  
  RESULTS
  Propofol (1.3 μg ml(-1)) and lidocaine (1 mg ml(-1)) reduced the baseline tone of bronchial rings (-14.45 ± 4.53% and -33.40 ± 1.07%, respectively, P < 0.05), whereas remifentanil had not such effect. Aminoguanidine prevented the relaxant effect of propofol. Propofol did not alter the bronchial contractile response to EFS following 30 min of treatment, whereas remifentanil enhanced the bronchial tension (133.83 ± 9.38%, control 101.93 ± 6.82%, P < 0.05 P < 0.05) and lidocaine completely abolished the contractility at 1 mg ml(-1) (P < 0.05). The desensitization of capsaicin-sensitive sensory nerves normalized the hyperresponsiveness induced by remifentanil (-26.77 ± 1.68%, P < 0.05). Significant BI antagonism (P < 0.001) was detected for propofol and lidocaine on the bronchial hyperresponsiveness induced by remifentanil.
  
  
  CONCLUSIONS
  Propofol and remifentanil may be used safely for bronchoscopy, although remifentanil should be associated with propofol or lidocaine to prevent the potential opioid-mediated bronchospasm.
authors: Department of System Medicine, University of Rome Tor Vergata, Rome, Italy.
authors: Paola
authors: P
authors: Rogliani
authors: Luigino
authors: L
authors: Calzetta
authors: Erino A
authors: EA
authors: Rendina
authors: Domenico
authors: D
authors: Massullo
authors: Mario
authors: M
authors: Dauri
authors: Barbara
authors: B
authors: Rinaldi
authors: Annalisa
authors: A
authors: Capuano
authors: Maria Gabriella
authors: MG
authors: Matera
mesh_terms: D001980:Bronchi / Q000187:drug effects; D001986:Bronchial Spasm / Q000503:physiopathology; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D066298:In Vitro Techniques; D008012:Lidocaine / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D010880:Piperidines / Q000494:pharmacology*; D015742:Propofol / Q000494:pharmacology*; D000077208:Remifentanil; D011984:Sensory Receptor Cells / Q000378:metabolism
chemical_list: D006993:Hypnotics and Sedatives; D010880:Piperidines; D008012:Lidocaine; D019001:Nitric Oxide Synthase; D000077208:Remifentanil; D015742:Propofol