Reduced spontaneous relaxation in immature guinea pig airway smooth muscle is associated with increased prostanoid release

摘要: Airway smooth muscle (ASM) from infant guinea pigs has less spontaneous relaxation during stimulation than ASM adults. Inhibition of cyclooxygenase (COX), which catalyzes the production prostanoids, increases this in and abolishes age differences, thus suggesting that prostanoids reduce ASM. In study, we investigated whether leukotrienes are also involved reducing relaxation; two COX isoforms, COX-1 COX-2, differentially regulate prostanoid release is developmentally regulated pig different groups, measured after electrical tracheal strips as well segments. Relaxation was studied absence presence a lipoxygenase inhibitor, cysteinyl leukotriene receptor-1 antagonist, or COX-2 inhibitor. We found inhibition antagonism did not increase at any age, excluding role for phenomenon. but COX-1, promoted relaxation. The basal more abundant tissue animals decreased significantly with age. Thromboxane B 2 most metabolite released all ages. Electrical epithelium removal affect difference release. conclude increased contributes to reduced immature compared older animals. By regulating relaxation, may play airway hyperresponsiveness young