Determination of an optimal axial-length tension for the study of isolated resistance arteries on a pressure myograph.
The effects of longitudinal stretch on vasoreactivity were assessed in isolated, pressurised arteries from the rat mesentery, rat mid-cerebral and human subcutaneous vascular beds. A stretch-dependent increase in reactivity was observed only in rat third order mesenteric arteries. Longitudinal stretch >> 20 % (force equal to 0.23 +/- 0.04 mN) optimises vasoconstrictor responses to noradrenaline and phenylephrine in rat third order mesenteric arteries. Stretch did not affect the vasoconstriction response to depolarisation by 30 mM K+ PSS in any of the arteries studied. Similarly, stretch had no affect on pressure-dependent myogenic responses in rat mid-cerebral arteries. Endothelium-independent and endothelium-dependent mechanisms of vasorelaxation were unaffected by stretch in rat third order mesenteric arteries. Likewise, stretch did not affect vasoreactivity in rat mid-cerebral and human subcutaneous resistance arteries. Our results show that longitudinal stretch in isobaric-mounted rat third order mesenteric arteries is an important methodological consideration. Considering our results, we recommend that isobaric-mounted rat third order mesenteric arteries are stretched >> 20 % to provide optimal experimental conditions for pharmacological studies.
Coats
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P
Vascular Assessment Group, Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow G4 OBA, UK.
Hillier
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C
D000818:Animals; D002536:Cerebral Arteries / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000502:physiology; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D009213:Myography / Q000379:methods*; D009638:Norepinephrine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D014661:Vasoconstriction / Q000502:physiology; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation
D014662:Vasoconstrictor Agents; D010656:Phenylephrine; D011188:Potassium; D009638:Norepinephrine