TY - JOUR T1 - Airway responsiveness in wheezy infants: evidence for functional beta adrenergic receptors. JF - Thorax JO - Thorax SP - 100 LP - 104 DO - 10.1136/thx.42.2.100 VL - 42 IS - 2 AU - A Prendiville AU - S Green AU - M Silverman Y1 - 1987/02/01 UR - http://thorax.bmj.com/content/42/2/100.abstract N2 - The effect of nebulised salbutamol on the bronchial response to nebulised histamine was studied in five wheezy infants aged 3-12 months. The response to doubling concentrations of up to 8 g/l of histamine was assessed by the change in the maximum flow at FRC (VmaxFRC), measured by flow-volume curves produced during forced expiration with a pressure jacket. The concentration of histamine required to provoke a 30% fall in VmaxFRC (PC30) was measured. All of the infants responded to low concentrations of histamine during control tests before and after nebulised saline (mean PC30 1.07 and 0.51 g/l). On a separate day there was a similar response to histamine before salbutamol (PC30 0.57 g/l), but after salbutamol the response was completely abolished up to the maximum concentration of histamine in all subjects (PC30 greater than 8 g/l). Thus wheezy infants have highly effective beta 2 adrenoceptors in intrathoracic airways. ER -