To investigate the impairment of beta-adrenoceptor responsiveness in human hypertension, we evaluated the effect of an oral salt load (400 mEq/day of NaCl for 7 days) on plasma catecholamine concentrations and beta-adrenoceptor-mediated effects in 11 young patients with mild essential hypertension. Responses of heart rate and plasma cAMP to isoproterenol administration were used as indices of beta-adrenoceptor responsiveness. Salt loading induced a significant reduction in the dose of isoproterenol required to raise the heart rate by 25 bpm (CD25) (from 7.6 ± 1.5 to 5.3 ± 0.9 μg, p < 0.05) and an increase in the slopes of the regression lines for heart rate changes and isoproterenol doses (ΔHR/IS) (from 3.3 ± 0.6 to 4.7 ± 0.7, p < 0.05) and for plasma cyclic AMP (cAMP) level changes and isoproterenol doses (ΔcAMP/IS) (from 0.3 ± 0.06 to 1.4 ± 0.3, p < 0.05). After salt loading there was a significant reduction in plasma catecholamine concentrations with a significant relationship between changes in upright plasma epinephrine levels and changes in CD25 (r = 0.904, p < 0.01) and in the slopes for ΔHR/IS (r = 0.983, p < 0.001) and ΔcAMP/IS (r = 0.922, p < 0.001). These results support the hypothesis that the impairment of beta-adrenoceptor sensitivity observed in human hypertension is associated with a beta-adrenoceptor overstimulation due to chronically elevated adrenergic tone.
Studies of the mechanisms underlying impairment of beta-adrenoceptor-mediated effects in human hypertension / B., Trimarco; Volpe, Massimo; B., Ricciardelli; G. B., Picotti; M. D., Galva; R., Petracca; M., Condorelli. - In: HYPERTENSION. - ISSN 0194-911X. - 5:4(1983), pp. 584-590.
Studies of the mechanisms underlying impairment of beta-adrenoceptor-mediated effects in human hypertension
VOLPE, Massimo;
1983
Abstract
To investigate the impairment of beta-adrenoceptor responsiveness in human hypertension, we evaluated the effect of an oral salt load (400 mEq/day of NaCl for 7 days) on plasma catecholamine concentrations and beta-adrenoceptor-mediated effects in 11 young patients with mild essential hypertension. Responses of heart rate and plasma cAMP to isoproterenol administration were used as indices of beta-adrenoceptor responsiveness. Salt loading induced a significant reduction in the dose of isoproterenol required to raise the heart rate by 25 bpm (CD25) (from 7.6 ± 1.5 to 5.3 ± 0.9 μg, p < 0.05) and an increase in the slopes of the regression lines for heart rate changes and isoproterenol doses (ΔHR/IS) (from 3.3 ± 0.6 to 4.7 ± 0.7, p < 0.05) and for plasma cyclic AMP (cAMP) level changes and isoproterenol doses (ΔcAMP/IS) (from 0.3 ± 0.06 to 1.4 ± 0.3, p < 0.05). After salt loading there was a significant reduction in plasma catecholamine concentrations with a significant relationship between changes in upright plasma epinephrine levels and changes in CD25 (r = 0.904, p < 0.01) and in the slopes for ΔHR/IS (r = 0.983, p < 0.001) and ΔcAMP/IS (r = 0.922, p < 0.001). These results support the hypothesis that the impairment of beta-adrenoceptor sensitivity observed in human hypertension is associated with a beta-adrenoceptor overstimulation due to chronically elevated adrenergic tone.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.