A comparison of cyclic AMP signaling system in rat aortic myocytes in primary culture and aorta.
Cyclic AMP (cAMP) metabolism has been studied in rat aortic myocytes grown in primary culture to characterize this second messenger system in vascular smooth muscle cells that retain responses to vasoactive drugs. For comparison, cAMP metabolism was also studied in the aorta from donor rats. Adenylate cyclase activity from myocytes and from the aorta was stimulated to a similar degree by GTP, NaF, or forskolin, and the enzyme activation produced by isoproterenol or vasoactive intestinal polypeptide was observed only in the presence of GTP. A cAMP phosphodiesterase activity was found in homogenates from cultured myocytes and aorta as well, and it was similarly stimulated by calmodulin in both cases. The rates of cAMP production and degradation were about seven-fold higher in cultured myocytes than in aorta. Basal levels of cAMP were also higher in the cultured cells than in the aorta. Hormones and drugs acting on adenylate cyclase or cAMP-phosphodiesterase in cell-free preparations altered the cAMP content of undisrupted cultured myocytes and aorta in the expected manner. Differences between cultured myocytes and aorta resided in the courses of drug-induced cAMP increases and in the magnitude of the cAMP response to isoproterenol, which was markedly increased in cultured myocytes compared with aorta. It is concluded that, despite some quantitative differences, the cAMP system of rat aortic myocytes grown in primary culture has characteristics similar to those displayed in rat isolated aorta. These cells are therefore suitable for studying the effects of drugs involving cAMP as a second messenger.
Schoeffter
P
P
Laboratoire de Pharmacologie Cellulaire et Moléculaire, Université Louis Pasteur de Strasbourg, Faculté de Pharmacie, Illkirch, France.
Lugnier
C
C
Travo
C
C
Stoclet
J C
JC
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
D005576:Colforsin; D014660:Vasoactive Intestinal Peptide; D000242:Cyclic AMP; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D000262:Adenylyl Cyclases; D007545:Isoproterenol; D015056:1-Methyl-3-isobutylxanthine