2.9. Histamine-induced bronchospasm in Guinea pigs

Taur et al.³² suggested the method for experimentally induced bronchospasm by histamine aerosol exposing to guinea pig. Briefly, guinea pig of either sex was selected and grouped (n = 5). Animals were treated with extracts of ET as shown in Table 2. Animals showed progressive dyspnea when they were challenged with 1% w/v histamine aerosol at 40 mmHg pressure from nebulizer of histamine chamber (M/s Inco Ambala, India). The time of onset of pre-convulsive dyspnea (PCD) recorded as pre-convulsive time (PCT). The moment when the PCD were recorded immediately the animals were relocated in the fresh air. This time of PCD was taken as day 0 value for the treatment. On day 5th, the PCT was recorded after 2 h of administration of ET extracts. Percent increase PCD was estimated using equation: % PCD = (1 – T₁/T₂) × 100 Where T₁ = time for PCD onset on day 0, T₂ = time for the PCD onset on day 5^th.

Effect of ET extracts on compound 48/80 induced mast cell degranulation in rats.