Reactivity of aorta and portal vein in germfree rats.
The responsiveness of conventional and germfree rat aortas and portal veins to vasoactive agents were compared in vitro. The results indicate: (1) aortas and portal veins from germfree rats exhibit an attenuated reactivity to angiotensin, vasopressin and epinephrine but not to KC1; (2) the dose-response curves for epinephrine and the peptides were shifted to the right concomitant with a decrease in maximum contractile tension, and (3) CaC12 dose-response curves obtained on potassium-depolarized aorta were not different from one another, whereas those obtained on portal veins from germfree animals were shifted to the right with a concomitant decrease in maximum response. In addition, aortas and portal veins from germfree rats were found to exhibit a higher total Ca content (but not Mg or water) when compared to conventional animals.
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000187:drug effects*; D002118:Calcium / Q000032:analysis; D002122:Calcium Chloride; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000494:pharmacology; D005856:Germ-Free Life; D066298:In Vitro Techniques; D008236:Lypressin / Q000494:pharmacology; D008274:Magnesium / Q000032:analysis; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000032:analysis / Q000187:drug effects*; D011169:Portal Vein / Q000187:drug effects*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D013268:Stimulation, Chemical; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D008236:Lypressin; D011189:Potassium Chloride; D008274:Magnesium; D002122:Calcium Chloride; D002118:Calcium; D004837:Epinephrine