Increased Plasma Noradrenaline During Severe Sodium Restriction Does Not Stimulate Platelet Release in Essential Hypertension

Summary

Seventeen 50-year old hypertensive men, previously untreated with blood pressure 157 ± 4/110 ± 2 mmHg (means ± SE) were given a low sodium diet for 2 weeks. During the second week, the diet was supplemented with potassium. The urinary Na⁺/K⁺ excretion ratio changed from 2:1 to 1:4 and 1:11, respectively.

Sympathetic noradrenergic tone increased considerably during the first week. Thus, venous plasma noradrenaline increased from 254 ± 22 to 347 ± 28 pg/ml (p <0.001) and arterial concentration from 253 ± 36 to 317 ± 42 pg/ml (n = 10, p <0.001). No significant change was observed in sympathetic adrenal tone as reflected by normal plasma adrenaline in venous (42 ± 5 vs 43 ± 6 pg/ml, ns) or arterial blood (71 ± 10 vs 82 ± 15 pg/ml, n = 10, ns) or in venous plasma concentration of the blood platelet release product beta-thromboglobulin (BTG) (50 ± 8 vs 43 ± 5 ng/ml, ns). During the second week sympathetic noradrenergic tone remained highly significantly elevated compared to baseline but still no change in plasma adrenaline or plasma BTG was found.

Thus, whereas sodium depletion did increase plasma noradrenaline concentration markedly in these hypertensive men, no change in adrenaline concentration was observed, and blood platelet release reaction was unchanged. Plasma noradrenaline within the physiological concentration range does not seem to serve as a regulator of in vivo platelet function.

Key words

Adrenaline - Beta-thromboglobulin - Catecholamines - Platelet function - Salt

• References

• 1 Ludlam CA, Moore S, Bolton AE, Pepper DS, Cash JD. The release of human platelet specific protein measured by a radioimmunoassay. Thromb Res 1975; 6: 543-548
• 2 Zahavi J, Kakkar VV. Beta-thromboglobulin - a specific marker of in vivo platelet release reaction. Thromb Haemostas 1980; 44: 23-29
• 3 Kjeldsen SE, Gjesdal K, Eide I, Aakesson I, Amundsen R, Foss OP, Leren P. Increased β-thromboglobulin in essential hypertension: Interactions between arterial plasma adrenaline, platelet function and blood lipids. Acta Med Scand 1983; 213: 369-373
• 4 Mehta J, Mehta P. Platelet function in hypertension and effect of therapy. Am J Cardiol 1981; 47: 331-334
• 5 Vlachakis ND, Aledort L. Hypertension and propranolol therapy: Effect on blood pressure, plasma catecholamines and platelet aggregation. Am J Cardiol 1980; 45: 321-325
• 6 McMillan R, Bakich MJ, Yelenosky RJ. The adrenaline binding site on human platelets. Br J Haematol 1979; 41: 597-604
• 7 O’Brien JR. Some effects of adrenaline and antiadrenaline compounds on platelets in vitro and in vivo. Nature 1963; 200: 763-764
• 8 Nordøy A, Rørvik TO. Some effects of adrenaline on rat platelets in vitro and in vivo. Scand J Clin Lab Invest 1965; 17 (Suppl. 84) 151-158
• 9 Lande K, Gjesdal K, Fønstelien E, Kjeldsen SE, Eide I. Effect of adrenaline infusion on platelet number, volume and release reaction. Thromb Haemostas 1985; 54: 450-453
• 10 Øian P, Lande K, Kjeldsen SE, Gjesdal K, Aakesson I, Eide I, Maltau JM. Enhanced platelet release reaction related to arterial plasma adrenaline and blood pressure in preeclampsia. Br J Gyn Obst 1986; 93: 548-553
• 11 Nordøy A, Gjesdal K, Jaeger S, Berntsen H. The effect of noradrenaline infusion on plasma and platelet lipids and platelet function in man. Thrombos Diathes Haemorrh 1975; 33: 328-334
• 12 Kjeldsen SE, Os I, Forsberg G, Aakesson I, Skjøtø J, Frederichsen P, Fønstelien E, Eide I. Dietary sodium intake increases vasopressin secretion in man. J Clin Hypertens 1985; 2: 123-131
• 13 Watson RD S, Esler MD, Leonard P, Korner PI. Influence of variation in dietary sodium intake on biochemical indices of sympathetic activity in normal man. Clin Exper Pharmacol Physiol 1984; 11: 163-170
• 14 MacGregor GA, Markandu ND, Best FE, Elder D, Can J, Sagnella GA, Squires M. Double-blind randomized cross-over trial of moderate sodium restriction in essential hypertension. Lancet 1982; 1: 351-355
• 15 Iimura O, Kijima T, Kikuchi K, Miyami A, Ando T, Nakao T, Tahigami Y. Studies on the hypotensive effect of high potassium intake in patients with essential hypertension. Clin Sci 1981; 61 (Suppl. 07) 77s-80s
• 16 Kjeldsen SE, Eide I. Arterial plasma adrenaline in essential hypertension (editorial). Scand J Clin Lab Invest 1984; 44: 271-274
• 17 Leren P, Askevold E-M, Foss OP, Frøili A, Grymyr D, Helgeland A, Hjermann I, Holme I, Lund-Larson PG, Norum KR. The Oslo Study. Cardiovascular disease in middle-aged and young Oslo men. Acta Med Scand 1975; Suppl 588
• 18 Peuler JD, Johnson GA. Simultaneous single radioenzymatic assay of plasma norepinephrine, epinephrine and dopamine. Life Sci 1977; 21: 625-636
• 19 Kjeldsen SE, Flaaten B, Eide I, Helgeland A, Leren P. Evidence of increased peripheral catecholamine release in patients with longstanding, untreated essential hypertension. Scand J Clin Lab Invest 1982; 42: 217-223
• 20 Clutter WE, Bier DM, Shah SD, Cryer PE. Epinephrine plasma metabolic clearance rates and physiologic thresholds for metabolic and hemodynamic action in man. J Clin invest 1980; 66: 94-101
• 21 Izzo J. Cardiovascular and hormonal effects of circulating norepinephrine. Hypertension 1983; 5: 787-789
• 22 Ashida T, Tanaka T, Yokouchi M, Kuramochi M, Deguchi F, Kimura G, Kojima S, Ito K, Ikeda M. Effect of dietary sodium on platelet α₂-adrenergic receptors in essential hypertension. Hypertension 1985; 7: 972-978
• 23 Egan B, Neubig R, Julius S. Pharmacologic reduction of sympathetic drive increases platelet alpha-2-receptor number. Clin Pharmacol Ther 1985; 38: 519-524
• 24 Cryer PE. Glucose counterregulation in man. Diabetes 1981; 30: 261-264
• 25 Ardlie NG, Cameron HA, Garrett J. Platelet activation by circulating levels of hormones: a possible link in coronary heart disease. Thromb Res 1984; 36: 315-322
• 26 Dawes J, Smith RC, Pepper DS. The release, distribution, and clearance of plasma β-thromboglobulin and platelet factor 4. Thromb Res 1978; 12: 857-861
• 27 Nara Y, Kihara M, Kanbe T, Horie R, Endo J, Yamori Y. Sodium-accelerated platelet aggregation in men predisposed to essential hypertension. Clin Sci 1982; 63 (Suppl. 08) 319s-23s
• 28 Sealey JE, Bühler FR, Laragh JH, Manning EL, Brunner HR. Aldosterone excretion: physiological variations in man measured by radioimmunoassay or double-isotope dilution. Circ Res 1972; 31: 367-378