Effect of vasoactive intestinal peptide (VIP) on propranolol-induced bronchoconstriction.
There is now considerable evidence in favor of vasoactive intestinal peptide (VIP) as a neurotransmitter of nonadrenergic noncholinergic nerves in the airways. The purpose of our study was to evaluate the influence of inhaled VIP on bronchomotor tone after a beta-adrenergic- and cholinergic-receptor blockage. The study was performed in six patients with asthma in 4 days. On the first day, a propranolol provocative dose producing a 20% change in FEV1 (PD20) was determined from the individual semilogarithmic dose-response curve. On the other days, the propranolol challenge was performed after inhalation of ipratropium bromide (40 micrograms), VIP (70 micrograms), and both drugs in randomized double-blind order. Statistical analysis was performed by two-way analysis of variance. The results demonstrated that mean propranolol PD20 was 0.14 mg (geometric mean + SD = 1.22). Ipratropium bromide administration, like VIP administration, significantly raised the PD20 value. The administration of both drugs elicited a further remarkable increase of mean propranolol PD20. The results demonstrated that inhaled VIP influences bronchomotor tone and that this effect is independent of the cholinergic blockage.
Crimi
N
N
Institute of Respiratory Diseases, University of Catania, Italy.
Palermo
F
F
Oliveri
R
R
Palermo
B
B
Vancheri
C
C
Polosa
R
R
Mistretta
A
A
D000328:Adult; D000336:Aerosols; D001249:Asthma / Q000503:physiopathology; D001985:Bronchial Provocation Tests; D001986:Bronchial Spasm / Q000139:chemically induced*; D001993:Bronchodilator Agents; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D009241:Ipratropium / Q000494:pharmacology; D008297:Male; D011433:Propranolol / Q000037:antagonists & inhibitors; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*
D000336:Aerosols; D001993:Bronchodilator Agents; D014660:Vasoactive Intestinal Peptide; D011433:Propranolol; D009241:Ipratropium