TY - JOUR
T1 - Characterization of renal ecto-phosphodiesterase
AU - Jackson, Edwin K.
AU - Ren, Jin
AU - Zacharia, Lefteris C.
AU - Mi, Zaichuan
PY - 2007/5
Y1 - 2007/5
N2 - In kidneys, stimulation of adenylyl cyclase causes egress of cAMP, conversion of cAMP to AMP by ecto-phosphodiesterase, and metabolism of AMP to adenosine by ecto-5′-nucleotidase. Although much is known about ecto-5′-nucleotidase, the renal ecto-phosphodiesterase remains uncharacterized. We administered cAMP (10 μM in the perfusate) to 12 different groups of perfused kidneys. AMP was measured in perfusate using ion trap mass spectrometry. In control kidneys (n = 19), basal renal secretion rate of AMP was 0.49 ± 0.08 and increased to 3.0 ± 0.2 nmol AMP/g kidney weight/min during administration of cAMP. A broad-spectrum phosphodiesterase (PDE) inhibitor (1,3-isobutyl-1-methylxanthine, 300 μM, n = 6) and an ecto-phosphodiesterase inhibitor (1,3-dipropyl-8-p- sulfophenylxanthine, 1 mM, n = 6) significantly attenuated cAMPinduced AMP secretion by 60 and 74%, respectively. Blockade of PDE1 (8-methoxymethyl-3- isobutyl-1-methylxanthine, 100 μM), PDE2 [erythro-9-(2-hydroxy-3-nonyl) adenine, 30 μM], PDE3 (milrinone, 10 μM; cGMP, 10 μM), PDE4 (Ro 20-1724 [4-(3-butoxy-4-methoxybenzyl)imidazolidin-2-one], 100 μM), PDE5 and PDE6 (zaprinast, 30 μM), and PDE7 [BRL-50481 (5-nitro-2,N,N- trimethylbenzenesulfonamide), 10 μM] did not alter renal ecto- phosphodiesterase activity. Administration of a concentration (100 μM) of dipyridamole that blocks PDE8 inhibited ecto-phosphodiesterase activity (by 44%). However, a lower concentration of dipyridamole (3 μM) that blocks PDE9, PDE10, and PDE11, but not PDE8, did not inhibit ecto-phosphodiesterase activity. These data support the conclusion that renal ecto-phosphodiesterase activity is not mediated by PDE1, PDE2, PDE3, PDE4, PDE5, PDE6, PDE7, PDE9, PDE10, or PDE11 and is inhibited by high concentrations of dipyridamole. Ecto-phosphodiesterase has some pharmacological characteristics similar to PDE8.
AB - In kidneys, stimulation of adenylyl cyclase causes egress of cAMP, conversion of cAMP to AMP by ecto-phosphodiesterase, and metabolism of AMP to adenosine by ecto-5′-nucleotidase. Although much is known about ecto-5′-nucleotidase, the renal ecto-phosphodiesterase remains uncharacterized. We administered cAMP (10 μM in the perfusate) to 12 different groups of perfused kidneys. AMP was measured in perfusate using ion trap mass spectrometry. In control kidneys (n = 19), basal renal secretion rate of AMP was 0.49 ± 0.08 and increased to 3.0 ± 0.2 nmol AMP/g kidney weight/min during administration of cAMP. A broad-spectrum phosphodiesterase (PDE) inhibitor (1,3-isobutyl-1-methylxanthine, 300 μM, n = 6) and an ecto-phosphodiesterase inhibitor (1,3-dipropyl-8-p- sulfophenylxanthine, 1 mM, n = 6) significantly attenuated cAMPinduced AMP secretion by 60 and 74%, respectively. Blockade of PDE1 (8-methoxymethyl-3- isobutyl-1-methylxanthine, 100 μM), PDE2 [erythro-9-(2-hydroxy-3-nonyl) adenine, 30 μM], PDE3 (milrinone, 10 μM; cGMP, 10 μM), PDE4 (Ro 20-1724 [4-(3-butoxy-4-methoxybenzyl)imidazolidin-2-one], 100 μM), PDE5 and PDE6 (zaprinast, 30 μM), and PDE7 [BRL-50481 (5-nitro-2,N,N- trimethylbenzenesulfonamide), 10 μM] did not alter renal ecto- phosphodiesterase activity. Administration of a concentration (100 μM) of dipyridamole that blocks PDE8 inhibited ecto-phosphodiesterase activity (by 44%). However, a lower concentration of dipyridamole (3 μM) that blocks PDE9, PDE10, and PDE11, but not PDE8, did not inhibit ecto-phosphodiesterase activity. These data support the conclusion that renal ecto-phosphodiesterase activity is not mediated by PDE1, PDE2, PDE3, PDE4, PDE5, PDE6, PDE7, PDE9, PDE10, or PDE11 and is inhibited by high concentrations of dipyridamole. Ecto-phosphodiesterase has some pharmacological characteristics similar to PDE8.
UR - http://www.scopus.com/inward/record.url?scp=34247236765&partnerID=8YFLogxK
U2 - 10.1124/jpet.106.119057
DO - 10.1124/jpet.106.119057
M3 - Article
C2 - 17308037
AN - SCOPUS:34247236765
SN - 0022-3565
VL - 321
SP - 810
EP - 815
JO - Journal of Pharmacology and Experimental Therapeutics
JF - Journal of Pharmacology and Experimental Therapeutics
IS - 2
ER -