title: Phorbol ester contracts rabbit thoracic aorta by increasing intracellular calcium and by activating calcium influx.
abstract: The ability of the phorbol ester tumor promoter, PDB, to activate contraction and stimulate calcium influx was investigated in rabbit thoracic aorta. PDB caused a strong, slowly-developing sustained contraction in physiological salt solution which was concentration-related (0.01 to 10.0 microM). PDB-induced contractions (0.1 microM) in calcium-free medium were attenuated but not prevented. PDB (1.0 microM) maximally stimulated Ca influx above basal control, vehicle = 39.2 +/- 2.2; PDB 1.0 microM = 70.7 +/- 6.7 mumoles Ca/kg tissue; N = 16, p less than 0.01). These data suggest that PDB activates rabbit thoracic aorta by a combination of intracellular and extracellular calcium dependent mechanisms.
authors.forename: M M
authors.initials: MM
authors.lastname: Gleason
authors.forename: S F
authors.initials: SF
authors.lastname: Flaim
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000502:physiology*; D005576:Colforsin / Q000494:pharmacology; D003593:Cytoplasm / Q000502:physiology; D005110:Extracellular Space / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D009543:Nifedipine / Q000494:pharmacology; D015240:Phorbol 12,13-Dibutyrate; D010703:Phorbol Esters / Q000494:pharmacology*; D011224:Prazosin / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology; D011817:Rabbits; D013997:Time Factors
chemical_list: D010703:Phorbol Esters; D005576:Colforsin; D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C; D009543:Nifedipine; D002118:Calcium; D011224:Prazosin