PMID- 1706799
OWN - NLM
STAT- MEDLINE
DCOM- 19910426
LR  - 20190724
IS  - 0160-2446 (Print)
IS  - 0160-2446 (Linking)
VI  - 16
IP  - 4
DP  - 1990 Oct
TI  - Modulation of adrenoceptor-mediated cardiovascular effects by short-term in vivo 
      infusion of isoproterenol in rats.
PG  - 584-93
AB  - After a 16-h in vivo infusion period of isoproterenol (400 micrograms/kg/h) from 
      a minipump implanted subcutaneously (s.c.) in rats, we observed an increase in 
      heart weight due to tissue edema. In isolated perfused heart preparations, the 
      EC50s of isoproterenol to induce positive inotropy and increase in coronary flow 
      were increased approximately 7 and 4 times, respectively. Isoproterenol 
      dose-response curves performed in trachea preparations, were shifted to the right 
      by about fivefold as compared with the control group. In the presence of 
      phentolamine, the isoproterenol induced maximal relaxation in the isolated aorta 
      from isoproterenol-pretreated animals was reduced from 46.5 to 9.2% as compared 
      with saline-pretreated rats. In the absence of phentolamine, the epinephrine 
      (EPI) and norepinephrine (NE) cumulative dose-response curves in this preparation 
      were not affected by isoproterenol pretreatment with respect to EC50 and maximal 
      effect. However, in the presence of phentolamine, the contractile response to a 
      supramaximal dose of NE (10 microM) amounted to 30 and 70% in the saline- and 
      isoproterenol-pretreated rats, respectively. In the presence of both phentolamine 
      and propranolol, a similar response of 70% was observed by this supramaximal dose 
      of agonist in the saline-pretreated rats as well. In anesthetized rats, 120 min 
      after removal of the minipumps, sodium nitroprusside induced increase in heart 
      rate (HR) was reduced after isoproterenol pretreatment, whereas for salbutamol 
      the decrease in diastolic blood pressure (DBP) was also reduced. As compared with 
      salbutamol, a marked increase was observed in the ratio of mean arterial blood 
      pressure (MAP) to HR for SNP after isoproterenol pretreatment. The 
      phenylephrine-induced increase in MAP was increased after isoproterenol 
      pretreatment. We conclude that in the pathogenesis of heart failure the 
      beta-adrenoceptor-mediated effects of catecholamines are attenuated and 
      alpha-adrenoceptor-mediated effects become progressively important.
FAU - Vleeming, W
AU  - Vleeming W
AD  - Department of Pharmacotherapy, Faculty of Pharmacy, University Utrecht, The 
      Netherlands.
FAU - van Rooij, H H
AU  - van Rooij HH
FAU - Wemer, J
AU  - Wemer J
FAU - Porsius, A J
AU  - Porsius AJ
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Cardiovasc Pharmacol
JT  - Journal of cardiovascular pharmacology
JID - 7902492
RN  - 0 (Receptors, Adrenergic, beta)
RN  - L628TT009W (Isoproterenol)
SB  - IM
MH  - Animals
MH  - Aorta, Thoracic
MH  - Cardiovascular System/*drug effects
MH  - Coronary Circulation/drug effects
MH  - Dose-Response Relationship, Drug
MH  - Hemodynamics/drug effects
MH  - In Vitro Techniques
MH  - Infusion Pumps
MH  - Isoproterenol/administration & dosage/*pharmacology
MH  - Male
MH  - Myocardial Contraction/drug effects
MH  - Rats
MH  - Rats, Inbred Strains
MH  - Receptors, Adrenergic, beta/*drug effects
MH  - Stimulation, Chemical
MH  - Time Factors
MH  - Trachea
EDAT- 1990/10/01 00:00
MHDA- 1990/10/01 00:01
CRDT- 1990/10/01 00:00
PHST- 1990/10/01 00:00 [pubmed]
PHST- 1990/10/01 00:01 [medline]
PHST- 1990/10/01 00:00 [entrez]
AID - 10.1097/00005344-199010000-00009 [doi]
PST - ppublish
SO  - J Cardiovasc Pharmacol. 1990 Oct;16(4):584-93. doi: 
      10.1097/00005344-199010000-00009.