Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Sympathoinhibitory and depressor responses to long-term infusion of nifedipine in spontaneously hypertensive rats on high-salt diet
Autore:
Huang, BS; Murzenok, PP; Leenen, FHH;
Indirizzi:
Univ Ottawa, Inst Heart, Hypertens Unit, Ottawa, ON K1Y 4W7, Canada Univ Ottawa Ottawa ON Canada K1Y 4W7 ens Unit, Ottawa, ON K1Y 4W7, Canada
Titolo Testata:
JOURNAL OF CARDIOVASCULAR PHARMACOLOGY
fascicolo: 6, volume: 36, anno: 2000,
pagine: 704 - 710
SICI:
0160-2446(200012)36:6<704:SADRTL>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
HEART-RATE; SENSITIVE HYPERTENSION; CALCIUM-ANTAGONISTS; CARDIAC-HYPERTROPHY; BLOOD-PRESSURE; ANGIOTENSIN-II; BRAIN OUABAIN; SODIUM-INTAKE; STRESS; AGENTS;
Keywords:
nifedipine; spontaneously hypertensive rats; high-salt diet; renal sympathetic nerve activity; tissue distribution; air stress; guanabenz; hexamethonium;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
33
Recensione:
Indirizzi per estratti:
Indirizzo: Leenen, FHH Univ Ottawa, Inst Heart, Hypertens Unit, H360,40 Ruskin St, Ottawa, ON K1Y4W7, Canada Univ Ottawa H360,40 Ruskin St Ottawa ON Canada K1Y 4W7 Canada
Citazione:
B.S. Huang et al., "Sympathoinhibitory and depressor responses to long-term infusion of nifedipine in spontaneously hypertensive rats on high-salt diet", J CARDIO PH, 36(6), 2000, pp. 704-710

Abstract

Short-term (by hour) intracerebroventricular (i.c.v.) or i.v. infusion of nifedipine at low rates evokes parallel decreases in renal sympathetic nerve activity (RSNA) and blood pressure (BP) in spontaneously hypertensive rats (SHR). In the present study, effects of long-term administration of nifedipine on BP and control of sympathetic tone were examined in SHR on a high-salt (8%) diet. From 6 to 8 weeks of age, for 2 weeks concomitant with taking a high-salt diet, rats were also treated with subcutaneous infusion of nifedipine at 10, 50, or 100 mug/kg/h or vehicle solvent as control using osmotic minipumps. At the end of the 2-week treatment period, mean arterial pressure (MAP), heart rate (HR), and RSNA at rest and in response to air-jetstress, i.c.v. injection of the alpha -adrenoceptor agonist guanabenz (25 mug), and i.v. injection of the ganglionic blocker hexamethonium were recorded in conscious rats. In rats on nifedipine 50 or 100 mug/kg/h, resting MAP was significantly lower (136 +/- 4 or 130 +/- 4 vs. 145 +/- 2 mm Hg in control rats, p < 0.05 for both), the sympathoinhibitory and depressor responses to i.c.v. guanabenz were significantly decreased, and the absolute decreases in MAP in response to i.v. injection of hexamethonium were significantly smaller. Sympathoexcitatory and presser responses to air-jet stress, however, were not affected by nifedipine. Infusion of nifedipine at the threerates for 2 weeks caused concentrations of plasma nifedipine in a dose-related manner. Nifedipine was not detected in tissues of rats treated with 10<mu>g/kg/h nifedipine but was present in brain and other tissues of rats treated with nifedipine at the two higher rates. Thus in SHR on high-salt intake long-term treatment with nifedipine at 50 or 100 mug/kg/h decreased resting BP and the sympathetic component in BP control. In addition to possible peripheral effects, long-term administration of nifedipine may also act centrally to decrease sympathetic activity and BP, likely by increasing activity in central pathways involving sympathoinhibition, but not in pathwaysinvolving sympathoexcitation as evaluated by air-stress.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 24/09/20 alle ore 08:18:29