Effects of nitric oxide system and osmotic stress on Aquaporin-1 in the postnatal heart.
Aquaporin-1 (AQP1) is expressed in the heart and its relationship with NO system has not been fully explored. The aims of this work were to study the effects of NO system inhibition on AQP1 abundance and localization and evaluate AQP1 S-nitrosylation in a model of water restriction during postnatal growth. Rats aged 25 and 50days (n=15) were divided in: R: water restriction; C: water ad libitum; RL: L-NAME (4mg/kgday)+water restriction; CL: L-NAME+water ad libitum. AQP1 protein levels, immunohistochemistry and S-nitrosylation (colocalization of AQP1 and S-nitrosylated cysteines by confocal microscopy) were determined in cardiac tissue. We also evaluated the effects of NO donor sodium nitroprusside (SNP) on osmotic water permeability of cardiac membrane vesicles by stopped-flow spectrometry. AQP1 was present in cardiac vascular endothelium and endocardium in C and CL animals of both ages. Cardiac AQP1 levels were increased in R50 and RL50 and appeared in cardiomyocyte plasma membrane. No changes in AQP1 abundance or localization were observed in R25, but RL25 group showed AQP1 presence on cardiomyocyte sarcolemma. AQP1 S-nitrosylation was increased in R25 group, without changes in the 50-day-old group. Cardiac membrane vesicles expressing AQP1 presented a high water permeability coefficient and pretreatment with SNP decreased water transport. Age-related influence of NO system on AQP1 abundance and localization in the heart may affect cardiac water homeostasis during hypovolemic state. Increased AQP1 S-nitrosylation in the youngest group may decrease osmotic water permeability of cardiac membranes, having a negative impact on cardiac water balance.
Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, IQUIMEFA-CONICET, Junín 956, Buenos Aires, Argentina. Electronic address: vnetti@conicet.gov.ar.
Vanina A
VA
Netti
Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, IQUIMEFA-CONICET, Junín 956, Buenos Aires, Argentina.
Agustina N
AN
Iovane
Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, IQUIMEFA-CONICET, Junín 956, Buenos Aires, Argentina.
Mariana C
MC
Vatrella
Laboratorio de Fisiopatogenia, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, Buenos Aires, Argentina.
Elsa
E
Zotta
Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, IQUIMEFA-CONICET, Junín 956, Buenos Aires, Argentina.
Andrea L
AL
Fellet
Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, IQUIMEFA-CONICET, Junín 956, Buenos Aires, Argentina.
Ana M
AM
Balaszczuk
D000818:Animals; D000831:Animals, Newborn; D051398:Aquaporin 1 / Q000378:metabolism*; D001794:Blood Pressure / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects; D006352:Heart Ventricles / Q000187:drug effects / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D008566:Membranes / Q000187:drug effects; D008954:Models, Biological; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000378:metabolism; D015538:Nitrosation; D009997:Osmotic Pressure / Q000187:drug effects; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D013599:Systole / Q000187:drug effects; D014867:Water
D020030:Nitric Oxide Donors; D014867:Water; D051398:Aquaporin 1; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester
Aquaporin-1; Dehydration; Heart; Nitric oxide; Postnatal growth