Dose-dependent autonomic dysfunction in chronic L-NAME-hypertensive diabetic rats.
This study investigated the effects of varying doses of L-NAME on arterial pressure (AP), baroreflex control, and heart rate (HR)/AP variability in the STZ-diabetic rat. Fifty-two male Wistar rats were injected with 50 mg/kg IV STZ (diabetes, D, n = 24) or citrate (controls, C, n = 28) 30 days before recordings. After 16 days, they received 14 days of oral L-NAME, 10 (H10) or 30 (H30) mg/kg, or water. Catheters were implanted into the femoral artery and vein (PE-10) for measurements in conscious rats; recorded data were analyzed on a beat-to-beat basis. Mean AP was higher in CH30 versus C and in DH10 and DH30 versus D rats. Reflex tachycardia was blunted in CH30 and DH30 rats (b = -1.81, -1.41, -0.48 in C, CH10, and CH30, respectively, P < 0.05 and b = -1.45, -1.19, -0.28 in D, DH10, and DH30, respectively, P < 0.05). Although HR and AP variability were reduced in CH30 and DH30 rats versus C and D rats, the DH30 rat had more accentuated dysfunction. All doses of L-NAME produced similar AP responses in experimental versus control groups, independent of the disease state (diabetes). Thus, autonomic dysfunction is more related to the L-NAME dose used and to the association of diabetes and hypertension than to AP values.
Balbinott
Adriana Werner
AW
Instituto de Cardiologia do Rio Grande do Sul/Fundação Universitária de Cardiologia, Av. Princesa Isabel 370, Santana 90.620-001 Porto Alegre, RS, Brazil.
Irigoyen
Maria Claudia
MC
Brasileiro-Santos
Maria do Socorro
Mdo S
Zottis
Berenice
B
de Lima
Nelson Gianni
NG
Passaglia
Juliana
J
Schaan
Beatriz D'Agord
BD
D000818:Animals; D001342:Autonomic Nervous System Diseases / Q000139:chemically induced* / Q000150:complications / Q000503:physiopathology; D017704:Baroreflex / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002908:Chronic Disease; D003921:Diabetes Mellitus, Experimental / Q000150:complications* / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000139:chemically induced* / Q000150:complications / Q000503:physiopathology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
D019331:NG-Nitroarginine Methyl Ester