Renal and systemic effects of aminoacids administered separately: comparison between L-arginine and non-nitric oxide donor aminoacids.
The present study examined the mechanisms of the renal effect of the NO-donor aminoacid, L-Arg and different non-NO-donor aminoacids, namely L-Asn, L-Ala, L-Gly L-Gln administered separately. In conscious, unrestricted Wistar rats, a bolus of L-Arg produced a short-lasting decrease in mean arterial pressure. No variations in mean arterial pressure were found with either L-Gly, L-Asn, L-Ala or L-Gln. This effect of L-Arg was inhibited by NwNLA, methylene blue and atropine and not affected by meclofenamate. Simultaneously, a dose-response diuretic and natriuretic effect was observed with all the aminoacids. In further experiments with L-Arg and L-Gly, this effect was associated with increased glomerular filtration rate, renal plasma flow, fractional sodium and free water excretion and urinary cyclic guanosine monophosphate. These effects of L-Arg and L-Gly were inhibited by NwNLA. On the contrary, no inhibition by NwNLA was detected on the diuretic, natriuretic and renal hemodynamic effects of L-Gln, and the diuretic and natriuretic effects of L-Asn or L-Ala. Our results show that all the assayed aminoacids were endowed of diuretic and natriuretic capabilities. Such effects were apparently related with a NO-mediated mechanism in the case of L-Arg and L-Gly, but not in the case of L-Gln, L-Asn or L-Ala, therefore suggesting that more than one mechanism is involved in the renal effect of the different aminoacids. Simultaneously, only L-Arg produced a NO-, cyclic guanosine monophosphate-dependent hypotensive effect, which was not shared by the other assayed aminoacids.
Cernadas
M R
MR
Laboratorio de Nefrología Fundación Jiménez Díaz, Universidad Autónoma, Madrid, Spain.
López-Farré
A
A
Riesco
A
A
Gallego
M J
MJ
Espinosa
G
G
Digiuni
E
E
Hernando
L
L
Casado
S
S
Caramelo
C
C
D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology*; D009320:Atrial Natriuretic Factor / Q000097:blood; D001285:Atropine / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects*; D006152:Cyclic GMP / Q000652:urine; D004231:Diuresis / Q000187:drug effects; D005998:Glycine / Q000494:pharmacology; D007668:Kidney / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009318:Natriuresis / Q000187:drug effects; D009569:Nitric Oxide / Q000378:metabolism*; D019335:Nitroarginine; D051381:Rats; D017208:Rats, Wistar
D000596:Amino Acids; D019335:Nitroarginine; D009569:Nitric Oxide; D001285:Atropine; D009320:Atrial Natriuretic Factor; D001120:Arginine; D006152:Cyclic GMP; D005998:Glycine