Constitutive nitric oxide synthase inhibition combined with histamine and serotonin receptor blockade improves the initial ovalbumin-induced arterial hypotension but decreases the survival time in brown norway rats anaphylactic shock.
Anaphylactic shock accidents after allergen exposure are frequent. After immunization with ovalbumin (OVA), a common dietary constituent, we evaluated the efficacy of pretreatment with histamine-receptor or serotonin-receptor blockers administered alone or in combination with a nitric oxide synthase inhibitor (L-NAME) on OVA-induced anaphylactic shock in Brown Norway rats. Animals were allocated to the following groups (n = 6 each): control (0.9% saline); diphenydramine (15 mg kg(-1)); cimetidine (20 mg kg(-1)); diphenydramine + cimetidine; dihydroergotamine (50 microg kg(-1)); diphenydramine + cimetidine + dihydroergotamine; L-NAME (100 mg/kg) alone or associated with diphenydramine, cimetidine, diphenydramine + cimetidine, dihydroergotamine, or diphenydramine + cimetidine + dihydroergotamine. Mean arterial blood pressure (MABP), heart rate (HR), and survival time were monitored for 60 min following treatment. The shock was initiated with i.v. OVA. The MABP drop after i.v. OVA was worsened by diphenydramine and was modestly attenuated by cimetidine, dihydroergotamine, or both together. L-NAME potentiated slightly the effects of cimetidine and dihydroergotamine by lessening the initial MABP decrease, but this transient effect was not sufficient to prevent the final collapse or to improve survival time. Decreased vasodilatory (prostaglandins E2), increased vasoconstrictory (thromboxane B2) prostaglandins, and unchanged leukotriene C4 concentrations were contributory to the overall hemodynamic changes. Thus, the combined blockade of vasodilator mediators (histamine, serotonin, and nitric oxide) slowed the MABP drop in anaphylactic shock, but did not improve survival. More studies are needed to understand these discordant effects.
Bellou
Abdelouahab
A
Experimental Nephrology Laboratory, Vandoeuvre les Nancy, 54505, France.
Lambert
Henri
H
Gillois
Pierre
P
Montémont
Chantal
C
Gerard
Philippe
P
Vauthier
Eliane
E
Sainte-Laudy
Jean
J
Longrois
Dan
D
Guéant
Jean Louis
JL
Mallié
Jean Pierre
JP
D000707:Anaphylaxis / Q000401:mortality*; D000818:Animals; D001158:Arteries / Q000473:pathology*; D002927:Cimetidine / Q000494:pharmacology; D004087:Dihydroergotamine / Q000494:pharmacology; D015232:Dinoprostone / Q000378:metabolism; D015777:Eicosanoids / Q000097:blood; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects; D006632:Histamine / Q000378:metabolism* / Q000494:pharmacology; D007022:Hypotension / Q000378:metabolism*; D017997:Leukotriene C4 / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000201:enzymology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D010047:Ovalbumin / Q000378:metabolism*; D011312:Pressure; D051381:Rats; D011914:Rats, Inbred BN; D011985:Receptors, Serotonin / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism / Q000494:pharmacology; D013929:Thromboxane B2 / Q000378:metabolism; D013997:Time Factors
D015777:Eicosanoids; D004791:Enzyme Inhibitors; D011985:Receptors, Serotonin; D017997:Leukotriene C4; D012701:Serotonin; D004087:Dihydroergotamine; D013929:Thromboxane B2; D002927:Cimetidine; D006632:Histamine; D010047:Ovalbumin; D019001:Nitric Oxide Synthase; D015232:Dinoprostone; D019331:NG-Nitroarginine Methyl Ester