Mechanisms of Increased Sensitivity to A(2) Adenosine Receptor Stimulation in Immature Rabbit Aortic Rings
| Autor: | McDaniel Nl, Girling Pw, Matherne Gp |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Agonist
medicine.medical_specialty Adenosine Endothelium medicine.drug_class Vasodilator Agents Aorta Thoracic Vasodilation Stimulation Adenosine-5'-(N-ethylcarboxamide) In Vitro Techniques Muscle Development Muscle Smooth Vascular Adenosine A1 receptor Internal medicine Cyclic AMP Purinergic P1 Receptor Agonists medicine Animals Pharmacology (medical) General Pharmacology Toxicology and Pharmaceutics Chemistry Isoproterenol Receptors Purinergic P1 Adenosine receptor Stimulation Chemical medicine.anatomical_structure Endocrinology cardiovascular system Endothelium Vascular Rabbits Blood vessel medicine.drug |
| Zdroj: | Developmental Pharmacology and Therapeutics. 20:121-128 |
| ISSN: | 2504-2505 0379-8305 |
| DOI: | 10.1159/000457552 |
| Popis: | Adenosine receptor-mediated vasodilation is increased in immature vessels compared to mature vessels. To determine the mechanism of this increased sensitivity, isolated vascular rings from mature and immature rabbits were studied to evaluate the contribution of the endothelium and the contribution of adenosine-dependent 3',5'-cyclic monophosphate (cAMP) to adenosine receptor-mediated relaxation. Dose responses were measured in endothelial-intact and nonendothelialized aortic rings using 5'-(N-ethylcarboxamido)-adenosine (NECA), a nonhydrolyzable adenosine agonist. Immature rings were more sensitive to NECA than mature rings as demonstrated by a lower ED50 and steeper slope of the dose-response curve. There was no effect on endothelial removal in immature rings while there was a significant decrease in response in mature rings. Despite being more sensitive to NECA, immature rings had less increase in cAMP (percent change from basal level) at maximal vasodilation than mature rings although cAMP did not change in either age at the ED50. The lack of change with endothelial removal in immature vessels suggests that the endothelium is not involved in the increased sensitivity of immature rings to NECA. The cAMP data suggests that other mechanisms for vasodilation are important at the ED50 for NECA in both ages. Maximal vasodilation with NECA on the other hand was associated with increases in cAMP although they were lower in the immature rings. |
| Databáze: | OpenAIRE |
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