| pubmed-article:6267671 | pubmed:abstractText | Thin strips of lung parenchyma from guinea pigs were mounted in an isolated tissue bath and placed under an initial tension of 1.2 gm. Drug-induced changes in resting tension were recorded isometrically upon the addition of representative alpha- and beta-adrenergic agonists. Lung strips relaxed following challenge with isoproterenol, 10(-9) to 10(-6)M (beta-adrenergic agonist), and contracted following challenge with phenylephrine, 10(-6) to 10(-4)M (alpha-adrenergic agonist). The responses of lung strips to norepinephrine, 10(-8) to 10(-4)M (mixed alpha- or beta-agonist) were influenced by the presence of either an alpha- or beta-adrenergic antagonist: pretreatment with phentolamine, 10(-5)M (alpha-antagonist) resulted in relaxant responses to norepinephrine, whereas pretreatment with propranolol, 10(-5)M (beta-antagonist) resulted in contractile responses. Cocaine, an uptake-1 inhibitor, potentiated the contractile effect of norepinephrine but not the relaxant effect of isoproterenol or norepinephrine. These data support the existence of alpha- and beta-adrenergic receptors mediating contraction and relaxation, respectively, in guinea pig lungs. | lld:pubmed |
