Haemophilus influenzae induces a potentiated increase in guinea-pig pulmonary resistance to histamine.
The human respiratory pathogen Haemophilus influenzae (H.i.) induced bronchial hyperreactivity to histamine (1.0-8.0 micrograms/100 g b.w. i.v.) in vivo in anaesthetized spontaneously breathing guinea-pigs. This hyperreactivity was caused by a potentiated increase in pulmonary resistance. Decreases in dynamic compliance did not differ. Atropine prevented the potentiation at 1.0 and 2.0 micrograms histamine/100 g b.w. These results show that H.i. induces bronchial hyperreactivity in vivo which is mediated by direct and reflex effects of histamine in the central airways.
D000403:Airway Resistance / Q000187:drug effects*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D006192:Haemophilus Infections / Q000503:physiopathology*; D006193:Haemophilus influenzae; D006632:Histamine / Q000494:pharmacology*; D008170:Lung Compliance / Q000187:drug effects; D008297:Male
D001285:Atropine; D006632:Histamine