The contribution of the sympathetic nervous system to the development and maintenance of experimental hypertension in the rat

Summary1. The degree of the decrease in the noradrenaline concentrations caused by 6-hydroxydopamine or immunosympathectomy was different in different areas of the cardiovascular system. 2. In rats or guinea-pigs 6-hydroxydopamine depleted the noradrenaline content of the heart by 90%, of the mesenteric vein by 80% and of the mesenteric artery and aorta by 30-60%. Immunosympathectomy elicited a 70% reduction in the cardiac noradrenaline but only a 50% reduction in the noradrenaline of the blood vessels of the rat. 3. The tyrosine hydroxylase activity of the heart, blood vessels, or adrenal glands was not significantly altered 2 weeks after 6-hydroxydopamine. Nor was the monoamine oxidase activity in heart or blood vessels changed. 4. The inconsistent ability of both 6-hydroxydopamine and immunosympathectomy to abolish experimental hypertension may be due to the partial persistence of noradrenaline and functional sympathetic nervous system activity in the blood vessels.

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Resistance of noradrenaline in blood vessels to depletion by 6‐hydroxydopamine or immunosympathectomy

Berkowitz¹,

Spector²,

Tarver³

1972

“…rats (Scientific Products), of 370-420 g body weight. Renal or DOCA/NaCl hypertension was induced by the methods described previously (Finch & Leach, 1970a). Chronic hypertension was considered to be present when systolic b!ood pressure in excess of 160 mmHg (1 mmHg=-1333 mbar) was maintained for a period of 8 weeks, and measured using the tail cuff method (Finch & Leach, 1970a).…”

Section: Methodsmentioning

confidence: 99%

Cardiovascular reactivity in the experimental hypertensive rat

Finch

1971

Self Cite

Summary1. In pithed preparations, deoxycorticosterone (DOCA) /NaCl-induced hypertensive rats showed increased cardiovascular reactivity to injected noradrenaline, DMPP, tyramine, angiotensin and to sympathetic nerve stimulation.2. Pithed, chronic renal hypertensive rats showed similar hyperreactivity to noradrenaline, DMPP and tyramine but responses to sympathetic nerve stimulation were within normal limits. 3. In the isolated, Krebs perfused mesentery preparation, vessels obtained from both DOCA/NaCl and renal hypertensive rats showed hyperreactivity to injected noradrenaline. Responses to periarterial nerve stimulation were also markedly increased in preparations from DOCA/NaCl hypertensive rats, while preparations from renal hypertensive rats showed this effect only at higher rates of stimulation (12 and 25 Hz).

“…These studies have demonstrated that a functional sympathetic nervous system is important for the development of hypertension. However, recent studies by Finch & Leach (1970a) showed that pretreatment of adult rats with 6-hydroxydopamine (6-OHDA) did not prevent the development of hypertension.…”

Section: Introductionmentioning

confidence: 99%

Importance of the sympathetic nervous system in the development of renal hypertension in the rat

Grewal¹,

Kaul²

1971

Summary1. Chemical sympathectomy with 6-hydroxydopamine (6-OHDA) prevented the development of renal hypertension in 80% of weanling male rats of the C.F. strain. 2. Adult male rats treated with 6-OHDA developed hypertension on bilateral clamping of the renal arteries. 3. Demedullation of the adrenal glands followed by 6-OHDA treatment in adult rats prevented the development of hypertension in 75% of them. 4. Weanling rats treated with 6-OHDA did not have any measurable catecholamines in their hearts up to 72-78 days after treatment. 5. Unlike the weanling rats, the hearts of adult rats (demedullated or with intact medulla) showed significant refilling (40-50%) of catecholamine stores 60 days after 6-OHDA treatment. 6. It is concluded that the functional sympathetic nervous system is important in the development of renal hypertension in the rat.