| Autor: |
Summers, R. J., Molnaar, P., Russell, F., Elnatan, J., Jones, C. R., Buxton, B. F., Chang, V., Hambley, J. |
| Zdroj: |
European Heart Journal; 1989, Vol. 10 Issue suppl_B, p11-21, 11p |
| Abstrakt: |
Quantitative autoradiography was used to determine the location and density of β1- and β2-adrenoceptors in the right atrium (RA), left ventricular free wall (LVFW), right ventricular free wall (RVFW), interventricular septum (IVS), right atrium from an area near the atrioventricular node (RAAV) and cardiac nerves (N) taken from a patient with end-stage cardiac failure. The densities of β-adrenoceptors detected by the non-selective β-adrenoceptor antagonist radioligand (−)-[125I] cyanopindolol (50PM) were 4·93 (N), 10·6 (RVFW), 12·2 (RA), 12·4 (IVS), 15·8 (LVFW) and 18·7 fmol (mg protein)−1 (RAAV). The proportion of β2-adrenoceptors ranged from 19·5% (RAAV) to 95% (N). RA taken from patients with ischaemic heart disease had a higher density of β-adrenoceptors (29·3 fmol (mg protein)−1). The results suggest that both β1- and β2-adrenoceptors are down-regulated in patients with end-stage cardiac failure. Positive inotropic responses were established to (−)-isoprenaline, RO363 (β1-selective), procaterol (β2-selective) and dopexamine in the absence or presence of the antagonist CGP20712A (β1-selective) or ICI 118,551 (β2-selective) in electrically driven human right atrial appendage strips. RO363 and procaterol were nearly full agonists in this preparation and produced their responses through activation of β1- or (β2-adrenoceptors, while dopexamine was a partial agonist which produced its inotropic responses through activation of both receptor subtypes. These studies demonstrate the presence and location of β1- and β2-adrenoceptors in the human heart. [ABSTRACT FROM PUBLISHER] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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