Negative chronotropic response to adenosine receptor stimulation in rat right atria after run training

Fernanda Priviero, Gilberto De Nucci, Edson Antunes, Angelina Zanesco

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

1. The aim of the present study was to evaluate the potency and maximal responses (Emax) to the adenosine receptor agonists N 6-cyclopentyladenosine (CPA), N-ethylcarboxamido-adenosine (NECA) and N6-(3-iodobenzyl)-5′-N-methylcarbax-amidoadenosine (IB-MECA) in right atria from trained rats. We also investigated the interaction between the training bradycardia and the sensitivity of the chronotropic response mediated by adenosine receptor stimulation. 2. Animals were submitted to run training for 60 min, 5 days a week, over a period of 8 weeks. Mean blood pressure and heart rate were measured in conscious animals. Right atria were isolated and concentration-response curves to CPA, NECA and IB-MECA were obtained. 3. A reduction in heart rate was found in trained rats, indicating that the training programme was successful in inducing physical conditioning. The three adenosine receptor agonists induced a concentration-dependent negative chronotropic response. The rank order of potency and Emax for the three adenosine receptor agonists was CPA > NECA > IB-MECA. 4. Dynamic exercise for 8 weeks did not alter the Emax for CPA, NECA and IB-MECA. Similarly, the potencies of CPA and NECA were not affected by run training, whereas the potency of IB-MECA was reduced (6.10 ± 0.09 vs 5.66 ± 0.10 for sedentary and trained groups, respectively). 5. In conclusion, run training for 8 weeks induced a desensitization of the chronotropic response to IB-MECA without changing the potency of CPA and NECA. These findings exclude the participation of adenosine receptors in the training bradycardia.

Original languageEnglish (US)
Pages (from-to)741-743
Number of pages3
JournalClinical and Experimental Pharmacology and Physiology
Volume31
Issue number10
DOIs
StatePublished - Oct 1 2004
Externally publishedYes

Fingerprint

Purinergic P1 Receptors
Heart Atria
Adenosine
Purinergic P1 Receptor Agonists
Bradycardia
Heart Rate
Blood Pressure
Education

Keywords

  • Adenosine agonist
  • Dynamic exercise
  • Heart rate
  • Potency

ASJC Scopus subject areas

  • Physiology
  • Pharmacology
  • Physiology (medical)

Cite this

Negative chronotropic response to adenosine receptor stimulation in rat right atria after run training. / Priviero, Fernanda; De Nucci, Gilberto; Antunes, Edson; Zanesco, Angelina.

In: Clinical and Experimental Pharmacology and Physiology, Vol. 31, No. 10, 01.10.2004, p. 741-743.

Research output: Contribution to journalArticle

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