Effects of L-NMMA and L-NNA on the selective ATP-induced enhancement of intratumoral blood flow.
We studied the effects of NG-monomethyl-L-arginine (L-NMMA) and N omega-nitro-L-arginine (L-NNA) on the selective ATP and adenosine-induced enhancement of intratumoral blood flow in rats measured by the hydrogen clearance method. Both adenosine and ATP produced a selective enhancement of the intratumoral blood flow. Neither L-NMMA nor L-NNA had a significant effect on either the CBF or the intratumoral blood flow. Adenosine-induced enhancement was not inhibited by L-NMMA or L-NNA. On the other hand, the ATP-induced enhancement was totally inhibited by both L-NMMA and L-NNA. The inhibitory action of L-NMMA against ATP was blocked by L-arginine, but not by D-arginine. It is suggested that the ATP-induced increase of intratumoral blood flow is evoked by nitric oxide synthesized from the endothelium of the intratumoral blood vessels.
Natori
Y
Y
Department of Neurosurgery, Kyushu University, Fukuoka, Japan.
Moriguchi
M
M
Fujiwara
S
S
Takeshita
I
I
Fukui
M
M
Iwaki
T
T
Kanaide
H
H
D000241:Adenosine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D001932:Brain Neoplasms / Q000098:blood supply*; D005910:Glioma / Q000098:blood supply*; D008297:Male; D019335:Nitroarginine; D051381:Rats; D011919:Rats, Inbred Strains; D012039:Regional Blood Flow / Q000187:drug effects; D014407:Tumor Cells, Cultured; D019323:omega-N-Methylarginine
D019335:Nitroarginine; D019323:omega-N-Methylarginine; D000255:Adenosine Triphosphate; D001120:Arginine; D000241:Adenosine