La histamina, el propanolol y la vagotomía para explorar el mecanismo de broncoconstricción en ratas y cobayos / Histamine, propanolol and vagotomy for exploring the vasoconstriction mechanism in rats and guinea pigs

Se explora el mecanismo de la constricción bronquial al investigar la interacción entre la respuesta a un fármaco broncoconstrictor (histamina), el control vagal a los pulmones y el receptor beta-adrenérgico. Las experiencias se llevan a cabo en ratas (un animal poco sensible a la histamina) y en cobayos (muy sensible en cuanto a la respuesta broncoconstrictora). Se demuestra el control neural autónomo del calibre bronquial y el papel del receptor beta-adrenérgico, que aumenta la broncoconstricción en las ratas cuando es bloqueado por propranolol, no sucede así con los cobayos, lo que sugiere una mayor población de estos receptores celulares en las ratas

Effect of exercise stress on the bronchospastic response of asthmatics in remission.

Twenty asthmatics in remission phase were subjected to exercise stress by running on level ground for 6 minutes and the degree of airway obstruction was measured by a peak flowmeter. The response was compared to 20 normal healthy volunteers. The prevalence of exercise induced asthma (EIA) was observed to be 75% among the asthmatics with male preponderance. A 100% response was seen in asthmatics of more than 25 years age. EIA was more, and so was the degree of response, as the duration of illness increased. The maximal fall in PEFR from its basal value was seen in the 6th minute after stopping the exercise in majority of the cases. No positive response was observed among the healthy controls.