caa a22 4500 469079037 CHVBK 20180323132944.0 cr unu---uuuuu 170328e19920101xx s 000 0 eng 10.1007/BF00175465 doi (NATIONALLICENCE)springer-10.1007/BF00175465 Activation of β2-adrenoceptors by isoprenaline and adrenaline enhances noradrenaline release in cortical kidney slices of young spontaneously hypertensive rats [Elektronische Daten] [L. Rump, M. Schuster, P. Schollmeyer] Summary: The aim of the present study was to investigate β-adrenoceptor modulation of noradrenaline release from sympathetic nerves in superfused cortical kidney slices of 4-week-old spontaneously hypertensive rats (SHR) and age-matched controls (WKY). After preincubation with 3H-noradrenaline the kidney slices were electrically stimulated in superfusion chambers. The stimulation induced (S-I) outflow of radioactivity was mainly composed of unmetabolized 3H-noradrenaline in both strains and thus taken as an index of noradrenaline release. There was a frequency-dependent (1.25-20 Hz) increase in the S-1 outflow of radioactivity. At all stimulation frequencies tested S-I outflow of radioactivity was similar or even slightly lower in SHR than in WKY kidney slices in either the absence or presence of cocaine (10 μmol/l). The non-selective β-adrenoceptor agonists isoprenaline (0.l gmol/1) and adrenaline (0.01 and 0.1 μmol/l) enhanced S-I outflow of radioactivity. The facilitatory effects of isoprenaline (0.1 μmol/l) and adrenaline (0.1 μmol/l) were blocked by the selective β2-adrenoceptor antagonist ICI 118551 (0.1 μmol/l) but not by the selective β1-adrenoceptor antagonist atenolol (0.3 μmol/l). The cell-permeable CAMP analogue 8-bromo-cAMP (300 μmol/l) enhanced S-1 outflow of radioactivity to a similar extent in both SHR and WKY kidney slices. A combination of 8-bromo-cAMP (300 μmol/l) and adrenaline (0.1 μmol/l) did not enhance S-1 outflow of radioactivity to a greater extent than 8-bromo cAMP (300 μmol/l) alone in both strains. However, the facilitatory effects of isoprenaline (0.1 μmol/l) and adrenaline (0.1 μmol/l) but not that of adrenaline (0.01 μmol/l) were significantly greater in SHR than in WKY. The results suggest that stimulation of prejunctional β2-adrenoceptors by adrenaline even in the absence of a-adrenoceptor blockade enhances noradrenaline release in kidney cortex of young SHR and WKY. This β2-adrenoceptor mediated effect may possibly be dependent on cAMP formation. The greater facilitatory effects of isoprenaline (0.1 μmol/l) and adrenaline (0.1 μmol/l) in SHR as compared to WKY are in accord with receptor binding studies which show a higher density of β2-adrenoceptors in SHR than in WKY kidney cortex. Springer-Verlag, 1992 3H-noradrenaline release nationallicence SHR nationallicence Kidney nationallicence Prejunctional β-adrenoceptors nationallicence Adrenaline nationallicence Isoprenaline nationallicence cAMP nationallicence SHR : Spontaneously hypertensive rats nationallicence WKY : WistarKyoto rats nationallicence cAMP : 3′-5′-cyclic adenosine monophosphate nationallicence S-I : stimulation induced nationallicence Rump L. Medizinische Universitatsklinik Freiburg, Innere Medizin IV, Hugstetter Strasse 55, W-7800, Freiburg, Federal Republic of Germany aut Schuster M. Medizinische Universitatsklinik Freiburg, Innere Medizin IV, Hugstetter Strasse 55, W-7800, Freiburg, Federal Republic of Germany aut Schollmeyer P. Medizinische Universitatsklinik Freiburg, Innere Medizin IV, Hugstetter Strasse 55, W-7800, Freiburg, Federal Republic of Germany aut Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 345/1(1992-01-01), 25-32 0028-1298 345:1<25 1992 345 210 https://doi.org/10.1007/BF00175465 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00175465 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Rump L. Medizinische Universitatsklinik Freiburg, Innere Medizin IV, Hugstetter Strasse 55, W-7800, Freiburg, Federal Republic of Germany aut NATIONALLICENCE 700 1- Schuster M. Medizinische Universitatsklinik Freiburg, Innere Medizin IV, Hugstetter Strasse 55, W-7800, Freiburg, Federal Republic of Germany aut NATIONALLICENCE 700 1- Schollmeyer P. Medizinische Universitatsklinik Freiburg, Innere Medizin IV, Hugstetter Strasse 55, W-7800, Freiburg, Federal Republic of Germany aut NATIONALLICENCE 773 0- Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 345/1(1992-01-01), 25-32 0028-1298 345:1<25 1992 345 210 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer