PMID- 6327523
OWN - NLM
STAT- MEDLINE
DCOM- 19840711
LR  - 20190722
IS  - 0194-911X (Print)
IS  - 0194-911X (Linking)
VI  - 6
IP  - 2 Pt 2
DP  - 1984 Mar-Apr
TI  - Decreased isoproterenol-induced "down"-regulation of beta-adrenergic receptors in 
      the myocardium of SHR.
PG  - I31-9
AB  - The number of cardiac beta-adrenergic receptors and the activity of 
      isoproterenol-stimulated adenylate cyclase are lower in spontaneously 
      hypertensive rats (SHRs) and may account for diminished inotropic responsiveness 
      to beta-agonists. Differences in isoproterenol-induced desensitization of the 
      cardiac adenylate cyclase system between 14- to 16-week-old SHRs and Wistar-Kyoto 
      (WKY) controls were studied using cardiac membranes, isolated cardiac myocytes, 
      and intact animals. In both animal strains, the isoproterenol-induced "loss" of 
      beta-adrenergic receptors in the cardiac membranes required adenosine 
      triphosphate (ATP), magnesium (Mg2+), and guanosine 5'-triphosphate (GTP). The 
      ATP and Mg2+ requirement may reflect a crucial role for a phosphorylation step, 
      since desensitization was prevented by cordycepin, a nonspecific phosphorylation 
      inhibitor. In both isolated myocytes and intact animals, isoproterenol induced a 
      redistribution of the beta-adrenergic receptors (but not of adenylate cyclase) 
      from the cell membrane to the cytosol. Internalization of the receptors was not 
      secondary to the loss of membrane fragments to the cytosol, since the receptors 
      sequestered in a fraction devoid of cell surface markers. In all three 
      preparations, the extent of isoproterenol-induced "loss" of beta-receptors and 
      isoproterenol-stimulated adenylate cyclase was considerably lower in SHRs than 
      WKYs. This difference appeared to be due to a reduced capacity of isoproterenol 
      to induce translocation of beta-receptors from the membranes to the cytosol of 
      SHRs, because of a change in the physical properties of either the beta-receptors 
      themselves or the membranes into which they were embedded.
FAU - Limas, C J
AU  - Limas CJ
FAU - Limas, C
AU  - Limas C
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PL  - United States
TA  - Hypertension
JT  - Hypertension (Dallas, Tex. : 1979)
JID - 7906255
RN  - 0 (Receptors, Adrenergic, beta)
RN  - 9Y8NXQ24VQ (Propranolol)
RN  - L628TT009W (Isoproterenol)
RN  - X4W3ENH1CV (Norepinephrine)
RN  - YKH834O4BH (Epinephrine)
SB  - IM
MH  - Animals
MH  - Cell Membrane/physiology
MH  - Dose-Response Relationship, Drug
MH  - Epinephrine/pharmacology
MH  - Heart/drug effects/*physiopathology
MH  - Heart Ventricles/physiopathology
MH  - Hypertension/*physiopathology
MH  - In Vitro Techniques
MH  - Isoproterenol/*pharmacology
MH  - Male
MH  - Norepinephrine/pharmacology
MH  - Propranolol/pharmacology
MH  - Rats
MH  - Rats, Inbred Strains
MH  - Rats, Mutant Strains
MH  - Receptors, Adrenergic, beta/drug effects/*physiology
MH  - Ventricular Function
EDAT- 1984/03/01 00:00
MHDA- 1984/03/01 00:01
CRDT- 1984/03/01 00:00
PHST- 1984/03/01 00:00 [pubmed]
PHST- 1984/03/01 00:01 [medline]
PHST- 1984/03/01 00:00 [entrez]
AID - 10.1161/01.hyp.6.2_pt_2.i31 [doi]
PST - ppublish
SO  - Hypertension. 1984 Mar-Apr;6(2 Pt 2):I31-9. doi: 10.1161/01.hyp.6.2_pt_2.i31.