Airway responsiveness in wheezy infants: evidence for functional beta adrenergic receptors.
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.
Prendiville
A
A
Department of Paediatrics and Neonatal Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London.
Green
S
S
Silverman
M
M
D000420:Albuterol / Q000008:administration & dosage / Q000494:pharmacology*; D001980:Bronchi / Q000187:drug effects* / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005652:Functional Residual Capacity; D006632:Histamine / Q000008:administration & dosage; D006633:Histamine Antagonists; D006801:Humans; D007223:Infant; D009330:Nebulizers and Vaporizers; D011943:Receptors, Adrenergic, beta / Q000502:physiology; D012135:Respiratory Sounds / Q000503:physiopathology*
D006633:Histamine Antagonists; D011943:Receptors, Adrenergic, beta; D006632:Histamine; D000420:Albuterol