Document Detail

Adrenergic receptors and the regulation of vascular resistance in bullfrog tadpoles (Rana catesbeiana).
MedLine Citation:
PMID:  1401339     Owner:  NLM     Status:  MEDLINE    
Vascular adrenergic sensitivity to exogenous catecholamines was examined in tadpoles of the American bullfrog (Rana catesbeiana), ranging from stage III to XIV. Central arterial blood pressure was measured in decerebrate bullfrog tadpoles to determine a reasonable initial infusion pressure. Solutions of epinephrine and phenylephrine were infused into the vasculature of pithed tadpoles, and the resulting changes in vascular resistance (Rv) were used to construct log dose-response relationships. Epinephrine infusion produced a dose-dependent increase in Rv (EC50 = 5.3 x 10(-7) M), which could be reversed by sodium nitroprusside (a smooth muscle relaxant) and blocked by phenoxybenzamine (an alpha-adrenergic antagonist). Larval Rv also increased with infusion of the alpha-agonist phenylephrine (EC50 = 7.4 x 10(-8) M). Infusion of 10(-6) M isoproterenol (a beta-agonist) largely reversed the phenylephrine-induced increase in Rv. These results indicate that the capacity exists for both alpha-mediated vasoconstriction and beta-mediated vasodilation early in bullfrog ontogeny. Neither initial Rv nor the responses to infused epinephrine or phenylephrine were significantly correlated to development over the range of larval stages used in this study.
P B Kimmel
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology     Volume:  162     ISSN:  0174-1578     ISO Abbreviation:  J. Comp. Physiol. B, Biochem. Syst. Environ. Physiol.     Publication Date:  1992  
Date Detail:
Created Date:  1992-11-13     Completed Date:  1992-11-13     Revised Date:  2009-06-08    
Medline Journal Info:
Nlm Unique ID:  8413200     Medline TA:  J Comp Physiol B     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  455-62     Citation Subset:  IM    
Department of Zoology, University of Massachusetts, Amherst 01003-0027.
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MeSH Terms
Blood Pressure / drug effects,  physiology
Epinephrine / pharmacology
Isoproterenol / pharmacology
Larva / physiology
Phenylephrine / pharmacology
Rana catesbeiana / physiology*
Receptors, Adrenergic / drug effects,  physiology*
Vascular Resistance / drug effects,  physiology*
Reg. No./Substance:
0/Receptors, Adrenergic; 51-43-4/Epinephrine; 59-42-7/Phenylephrine; 7683-59-2/Isoproterenol

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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