Haemodynamic and humoral consequences of chronic infusion of vasopressin in conscious rats.
1. To determine the long-term haemodynamic and humoral effects of arginine vasopressin (AVP), a chronic intravenous infusion of AVP was performed in conscious Wistar normotensive rats. 2. AVP (1, 10, 50 or 100 ng/h) or saline as a vehicle control was infused continuously into the right jugular vein at a rate of 1 microL/h using an osmotic minipump for 7 days. 3. As a result, significant elevations of systolic blood pressure were observed in association with increases in plasma AVP concentration. Significant decreases in heart rate were observed during infusion of 100 ng/h of AVP. Mean arterial pressures measured directly on the sixth day of infusion were significantly higher in the rats given 50 ng/h (125 +/- 3 mmHg) or 100 ng/h (125 +/- 2 mmHg) compared with control rats (117 +/- 2 mmHg). Intravenous injection of the V1 antagonist, d(CH2)5Tyr(Me)AVP, significantly reduced the elevated mean arterial pressure induced by 50 or 100 ng/h of AVP (-7 +/- 4 and -11 +/- 2 mmHg, respectively). Plasma renin and norepinephrine concentrations were not affected by AVP infusion, while plasma epinephrine concentration was lower in the rats given 100 ng/h of AVP. Intravenous infusion of AVP did not alter bodyweight, serum electrolytes or osmolality. 4. These results suggest that AVP has a long-term pressor effect which is attributable to its vasoconstrictor action in conscious rats.
Tsuchihashi
T
T
Second Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Takata
Y
Y
Nakao
Y
Y
Tominaga
M
M
Takishita
S
S
Kobayashi
K
K
Abe
I
I
Fujishima
M
M
D000818:Animals; D001127:Arginine Vasopressin / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000097:blood / Q000494:pharmacology*; D001774:Blood Chemical Analysis; D001794:Blood Pressure / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D004573:Electrolytes / Q000097:blood; D004837:Epinephrine / Q000097:blood; D006339:Heart Rate / Q000187:drug effects*; D007262:Infusions, Intravenous; D008297:Male; D009638:Norepinephrine / Q000097:blood; D009994:Osmolar Concentration; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D012083:Renin / Q000097:blood; D014661:Vasoconstriction / Q000187:drug effects
D004573:Electrolytes; D001127:Arginine Vasopressin; C025043:vasopressin, 1-(1-mercaptocyclohexaneacetic acid)-2-(O- methyl-L-tyrosine)-8-L-arginine-; D012083:Renin; D009638:Norepinephrine; D004837:Epinephrine