Experimental renal anaphylaxis: release of histamine and study of its effect on renal perfusion

Immune release of histamine and other lipid mediators from guinea-pig isolated kidney: antagonism by BN-52021

The ability of a specific PAF-receptor antagonist, BN-52021, to control the release of mediators of anaphylaxis from actively sensitized (ovalbumin) guinea-pig has been investigated "in vitro". BN-52021 perfused through the kidney at different molar concentrations (1 x 10(-4)-1 x 10(-5)-1 x 10(-6] prior to antigen challenge neither modified the basal values of perfusion pressure nor stimulated mediator release from the organ. On the contrary, the compound antagonized in a concentration dependent way both vasoconstriction of the renal vessels and the increase in the perfusate of histamine, TXB2 and SRS-A due to antigenic shock. The antagonistic activity of BN-52021 was very consistent at 1 x 10(-4) M at which concentration the immunological release of histamine and TXB2 was reduced by 75%. The beneficial effect of BN-52021 in experimental anaphylaxis of the kidney may have some therapeutic implications principally in those pathological conditions where an abnormal increase of renal histamine and other mediators may compromise the haemodynamic function of this organ.

Role of thromboxane A2, leukotriene C4 and histamine in the antigen-induced vasoconstriction in perfused, sensitized guinea-pig kidney

The existence of a role for TXA2, histamine, and possibly LTC4 in the antigen-induced renal vasoconstriction in isolated, perfused kidney of sensitized guinea-pigs is demonstrated.

Substance P and Arg-Pro-Lys-Pro-NH-C12-H25-induced mediator release from different mast cell subtypes of rat and guinea-pig

Histamine was released from mast cells in isolated perfused heart and kidney of the rat, but not from mast cells in guinea-pig tissues, by a substance P (SP) analogue (SP(1-4)-NH-C12H25), SP(1-4)-C12 for abbreviation. This peptide also released histamine from peritoneal mast cells and basophil leucocytes of the rat. Substance P itself was compared with SP(1-4)-C12 and some structurally related peptides and showed weaker activity. SP(1-4)-C12 also released leukotrienes C4, D4, E4 and thromboxane B2 from rat heart. However, there was little effect on heart rate and force of contraction and no effect on perfusion pressure (vascular resistance) of either rat heart or kidney. The findings demonstrate the structural requirements for histamine release by SP (a possible mediator of 'neurogenic' inflammation), the metabolic energy-dependence of the release process and the functional heterogeneity and interspecies differences in mast cell populations.

Anaphylatoxin-induced release of histamine from in vitro perfused guinea pig kidney

The effect of porcine C5a des Arg and C3a, given as a bolus injection, in the isolated constant flow pump-perfused guinea-pig kidney was investigated. Only C5a des Arg showed activity which was manifested by a dose-dependent increase in perfusion pressure (PP, due to vasoconstriction) and histamine release. Although histamine release was substantial, it alone could not account for the increase in PP. The two more likely causes are a direct vasoconstrictor effect and the release of other mediators.