Concentration-related differences in the effects of the Ca2+ agonist Bay K 8644 in human bronchus in vitro.
1. In human isolated bronchial muscle Bay K 8644 (1 nM-1 microM) increased the force of contraction. In concentrations greater than 1 microM (in sensitized tissues), and 10 microM (in control), Bay K 8644 relaxed tissues to below their pretreatment baseline tension. 2. In control tissues contracted with methacholine or LTD4, Bay K 8644 (10 microM) produced a further small contraction; Bay K 8644 (100 microM) relaxed the tissues below baseline. 3. In tissues contracted with histamine, Bay K 8644 (10-100 microM) produced only relaxation. 4. Bay K 8644 therefore has both Ca2+ agonist and Ca2+ antagonist properties, the calcium agonist activity is more pronounced in sensitized tissues.
Raeburn
D
D
Department of Pharmacology and Experimental Therapeutics, Louisiana State University Medical Center, New Orleans 70112.
Roberts
J A
JA
Rodger
I W
IW
Thomson
N C
NC
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology*; D000403:Airway Resistance / Q000187:drug effects*; D001980:Bronchi / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D016210:Methacholine Chloride; D008688:Methacholine Compounds / Q000494:pharmacology; D013189:SRS-A / Q000494:pharmacology
D008688:Methacholine Compounds; D013189:SRS-A; D016210:Methacholine Chloride; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester