TY - JOUR
T1 - Coexistence and localization of β
1
- and β
2
-adrenoceptors in the human heart
AU - Summers, R. J.
AU - Molnaar, P.
AU - Russell, F.
AU - Elnatan, J.
AU - Jones, C. R.
AU - Buxton, B. F.
AU - Chang, V.
AU - Hambley, J.
PY - 1989/1/1
Y1 - 1989/1/1
N2 -
Quantitative autoradiography was used to determine the location and density of β
1
- and β
2
-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 (-)-[
125
I]cyanopindolol (50 pM) 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 β
2
-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 β
1
- and β
2
-adrenoceptors are down-regulated in patients with end-stage cardiac failure. Positive inotropic responses were established to (-)-isoprenaline, RO363 (β
1
-selective), procaterol (β
2
-selective) and dopexamine in the absence or presence of the antagonist CGP 20712A (β
1
-selective) or ICI 118,551 (̄
2
-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 β
1
- or β
2
-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 β
1
- and β
2
-adrenoceptors in the human heart.
AB -
Quantitative autoradiography was used to determine the location and density of β
1
- and β
2
-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 (-)-[
125
I]cyanopindolol (50 pM) 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 β
2
-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 β
1
- and β
2
-adrenoceptors are down-regulated in patients with end-stage cardiac failure. Positive inotropic responses were established to (-)-isoprenaline, RO363 (β
1
-selective), procaterol (β
2
-selective) and dopexamine in the absence or presence of the antagonist CGP 20712A (β
1
-selective) or ICI 118,551 (̄
2
-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 β
1
- or β
2
-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 β
1
- and β
2
-adrenoceptors in the human heart.
UR - http://www.scopus.com/inward/record.url?scp=0024354017&partnerID=8YFLogxK
M3 - Article
C2 - 2553407
AN - SCOPUS:0024354017
SN - 0195-668X
VL - 10
SP - 11
EP - 21
JO - European Heart Journal
JF - European Heart Journal
IS - SUPPL. B
ER -
