Adenosine modulates the (Na(+)+K(+))ATPase activity in malpighian tubules isolated from Rhodnius prolixus.
The role of adenosine on regulation of the (Na(+)+K(+))ATPase activity present in the Malpighian tubules isolated from Rhodnius prolixus was investigated. Adenosine decreases the (Na(+)+K(+)) ATPase specific activity by 88%, in a dose-dependent manner, with maximal effect at a concentration of 10(-9) M. This effect was mimicked by N(6)-cyclohexyladenosine (CHA) at 10(-8) M, an agonist for A(1) adenosine receptor, and was reversed by 10(-9) M 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), an antagonist for A(1) adenosine receptor. On the other hand, 5'-N-ethyl-carboxamide adenosine (NECA), an agonist for A(2) adenosine receptor, used in the range of 10(-9)-10(-5) M, did not change the (Na(+)+K(+))ATPase specific activity. In the same way, 10(-8) M 3, 7-dimethyl-1-propargylxanthine (DMPX), an antagonist for A(2) adenosine receptor, did not modify the inhibitory effect of adenosine. These data suggest that the inhibitory effect of adenosine on the (Na(+)+K(+))ATPase specific activity present in Malpighian tubules from Rhodnius prolixus is mediated by A(1) adenosine receptor activation. Arch.
Caruso-Neves
C
C
Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Monteiro
S O
SO
de Oliveira
C F
CF
Filho
C C
CC
Lopes
A G
AG
D000241:Adenosine / Q000494:pharmacology*; D019830:Adenosine-5'-(N-ethylcarboxamide) / Q000494:pharmacology; D000818:Animals; D008317:Malpighian Tubules / Q000201:enzymology*; D018047:Receptors, Purinergic P1 / Q000378:metabolism; D012239:Rhodnius / Q000187:drug effects / Q000201:enzymology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013805:Theobromine / Q000031:analogs & derivatives / Q000494:pharmacology; D014970:Xanthines / Q000494:pharmacology
D018047:Receptors, Purinergic P1; D014970:Xanthines; D019830:Adenosine-5'-(N-ethylcarboxamide); C057837:3,7-dimethyl-1-propargylxanthine; C051360:1,3-dipropyl-8-cyclopentylxanthine; D000254:Sodium-Potassium-Exchanging ATPase; D000241:Adenosine; D013805:Theobromine