Endothelin antagonism does not affect adrenal catecholamine secretion and system haemodynamics during acute stress in Wistar rats

Citation
Dv. Zaretsky et al., Endothelin antagonism does not affect adrenal catecholamine secretion and system haemodynamics during acute stress in Wistar rats, J CARDIO PH, 36, 2000, pp. S374-S376
Citations number
9
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
Journal title
JOURNAL OF CARDIOVASCULAR PHARMACOLOGY
ISSN journal
01602446 → ACNP
Volume
36
Year of publication
2000
Supplement
1
Pages
S374 - S376
Database
ISI
SICI code
0160-2446(2000)36:<S374:EADNAA>2.0.ZU;2-R
Abstract
In the present work we evaluated the role of circulating endothelin-1 (ET-1 ) in haemodynamics and the adrenal medulla responses to stress using PD-142 893, a mixed endothelin-A- and -B- (ETA/ETB) receptor antagonist. Male Wist ar rats were chronically instrumented with arterial and venous catheters an d a microdialysis probe placed into the adrenal medulla. Stress was induced by a 1 h period of immobilization. PD-142893 was infused (20 mug/kg/min) f or 90 min starting 30 min before stress onset. Concentrations of norepineph rine and epinephrine in dialysate samples were measured by high-performance liquid chromatography (HPLC). At rest animals displayed a stable level of norepinephrine (85 +/- 34 pg/ml) and epinephrine (176 +/- 57 pg/ml) in adre nal perfusate and constant haemodynamic parameters. Stress increased adrena l secretion (norepinephrine 206 +/- 50%, epinephrine 202 +/- 45%) associate d with hypertension (peak 141 +/- 3 mmHg) and tachycardia (peak 505 +/- 5 b pm). No significant changes in haemodynamics or of plasma catecholamine lev els were observed during infusion of PD-142893. The antagonist did not sign ificantly change the stress-induced increase in catecholamine secretion, ta chycardia or hypertension. Thus, in Wistar rats, circulating ET-1 seems not to be essential for blood pressure control or adrenal catecholamine secret ion during acute stress.