TABLE 2

Tracheal smooth muscle contraction

Histamine- (3 × 10−6 M) or methacholine- (5 × 10−7 M) induced guinea pig isolated tracheal contractions in normal (first contraction and second contraction) and calcium free Krebs-Henseleit (KH) solution before (third contraction, fourth contraction, and fifth contraction), and after incubating for 30 minutes in normal KH solution (sixth contraction and seventh contraction).a

In mNNormal KH Solution 
(2.5 mM Ca2+)Ca2+-Free KH SolutionCa2+-Free KH Solution
Agonist1st2nd3rd4th5th6th7th
Histamine10.9 ± 2.811.9 ± 3.28.6 ± 3.32.6 ± 2.50.4 ± 0.86.5 ± 3.90.3 ± 0.9
Methacholine9.3 ± 2.510.4 ± 2.88.0 ± 2.71.5 ± 2.20.4 ± 0.14.4 ± 2.60.11 ± 0.3
In percentage (mean ± S.D.)I
Agonist1st2nd3rd4th5th6th7th
Histamine92.5 ± 8.010070.7 ± 14.822.9 ± 25.13.0 ± 6.352.7 ± 25.43.1 ± 10.1
Methacholine89.2 ± 5.810076.2 ± 12.413.3 ± 16.80.4 ± 1.142.0 ± 21.11.2 ± 2.9
  • a Values represent mean ± S.D. (n = 32–43).