The actions of endothelins−1 and −3 on the vascular and capsular smooth muscle of the isolated blood perfused spleen of the dog

Abstract

1 Endothelin-1 (ET-1), endothelin-3 (ET-3) and noradrenaline (NA) were administered as intra-arterial bolus injections into the isolated, blood-perfused spleen of the dog to assess agonist properties and relative molar potencies on the vascular and capsular smooth muscle. 2 An initial small vasodilatation was observed occasionally at low doses (1.0-i0pmol) of ET-1. 3 ET-1, ET-3 and NA all caused graded increases in splenic arterial vascular resistance. The molar ED50 for the splenic vasoconstrictor response to ET-1 was significantly less (P < 0.001) than that to ET-3; both peptides were significantly more potent as vasoconstrictor agents than NA. The maximum increase in splenic arterial vascular resistance was not significantly different for either ET-1, The time course of the splenic vasoconstrictor response to ET-1 was significantly (P < 0.01) longer than that to equieffective doses of ET-3 or NA. 5 The splenic vasoconstrictor responses to ET-1 and ET-3 were accompanied by reductions in spleen volume. The rank order of molar potency in causing splenic capsular contraction was ET-i > ET-3 > NA. The maximum reduction in splenic volume was significantly greater for NA than for either ET-i or ET-3. The two peptides (ET-1, ET-3) were equiefficacious in contracting splenic capsular smooth muscle. 6 The high molar potency of ET-1 as a splenic arterial vasoconstrictor, over 1,700 times more potent than NA, suggests that it may play an important local role in the control of splenic haemodynamics.

Proceedings of the Physiological Society, 17‐18 December 1992, Queen Mary and Westfield College Meeting: Poster Communications

“…ET-1 was injected intra-arterially as a bolus dose over the range 0.4-400 pmol; it caused graded increases in SAVR of prolonged duration accompanied by small changes in spleen weight confirming previous observations (Withrington et al 1992). In addition, ET-1 (at doses of 4.0, 40 and 200 pmol) caused graded increases in all three eicosanoids in the venous effluent; the mean (± S.E.M.)…”

Can We Continue Research in Splenectomized Dogs? <i>Mycoplasma haemocanis:</i> Old Problem – New Insight

“…Canine splenic contraction is mediated by endothelin and by norepinephrine via · 1 -adrenoceptors [9]. Of note, the splenic release of red cells is variable in dogs and negligible in humans [5].…”

Use of CPR in hemorrhagic shock, a dog model

“…Additional bleeding was needed in part due to dog's ability to respond with mobilization of blood from their spleen as described by previous studies. [13][14][15][16] All data points were recorded at 10-minute intervals through the PEA phase. At the conclusion of PEA, total blood loss was recorded.…”