title: Acidosis reduces the function and expression of α1D-adrenoceptor in superior mesenteric artery ofCapra hircus.
abstract: OBJECTIVE
  The objective of this study was to characterize the α1-adrenoceptor (α1-AR) subtypes and evaluate the effect of acidosis on α1-AR function and expression in goat superior mesenteric artery (GSMA).
  
  
  METHODS
  GSMA rings were mounted in a thermostatically controlled (37.0°C ± 0.5°C) organ bath containing 20 ml of modified Krebs-Henseleit solution, maintained at pHoof 7.4, 6.8, 6.0, 5.5, 5.0, and 4.5. Noradrenaline (NA)- and phenylephrine (PE)-induced contractile response was elicited in the absence or presence of endothelium and prazosin at pHoof 7.4, 6.0, and 5.0. The responses were recorded isometrically by an automatic organ bath connected to PowerLab and analyzed using Labchart 7.1.3 software. Expression of α1D-AR was compared at physiological and acidic pHousing reverse transcription-polymerase chain reaction (RT-PCR).
  
  
  RESULTS
  NA- and PE-induced contractile responses were attenuated proportionately with a decrease in extracellular pH (pHo), i.e. 7.4 → 6.8 → 6.0 → 5.5 → 5.0 → 4.5. Endothelium denudation increased the contractile response at both normal and acidic pHo. Prazosin (1 nM, 10 nM, and 0.1 μM) inhibited the NA- and PE-induced contractile response at pHo7.4 and the blocking effect of prazosin was potentiated at pHoof 6.0 and 5.0. RT-PCR analysis for α1D-AR in GSMA showed that the mRNA expression of α1D-AR was decreased under acidic pHoas compared to physiological pHo.
  
  
  CONCLUSIONS
  (i) Adrenergic receptor mediates vasoconstriction in GSMA under normal physiological pHo, and α1Dis the possible subtype involved in this event (ii) acidosis attenuates the vasocontractile response due to reduced function and expression of α1D-AR and also increased the release of endothelial-relaxing factors.
authors.affiliation: Department of Pharmacology and Toxicology, Faculty of Veterinary Sciences, Orissa University of Agriculture and Technology, Bhubaneswar, Odisha, India.
authors.forename: Ipsita
authors.initials: I
authors.lastname: Mohanty
authors.affiliation: Tumor Microenvironment and Animal Models, Institute of Life Sciences, Bhubaneswar, Odisha, India.
authors.forename: Sujit
authors.initials: S
authors.lastname: Suklabaidya
authors.affiliation: Department of Pharmacology and Toxicology, College of Veterinary Sciences and Animal Husbandry, Orissa University of Agriculture and Technology, Bhubaneswar, Odisha, India.
authors.forename: Subas Chandra
authors.initials: SC
authors.lastname: Parija
mesh_terms: D000138:Acidosis / Q000378:metabolism*; D058668:Adrenergic alpha-1 Receptor Antagonists / Q000494:pharmacology; D000818:Animals; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects; D006041:Goats; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D017538:Mesenteric Artery, Superior / Q000187:drug effects / Q000378:metabolism*; D009119:Muscle Contraction / Q000187:drug effects; D009638:Norepinephrine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D018340:Receptors, Adrenergic, alpha-1 / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014661:Vasoconstriction / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology
chemical_list: D058668:Adrenergic alpha-1 Receptor Antagonists; D018340:Receptors, Adrenergic, alpha-1; D014662:Vasoconstrictor Agents; D010656:Phenylephrine; D009638:Norepinephrine; D011224:Prazosin
keywords: Acidosis; Capra hircus; prazosin; superior mesenteric artery; α1D-adrenoceptor