Pertussis toxin and N-ethylmaleimide inhibit histamine- but not calcium ionophore-induced endothelium-dependent relaxation.
Endothelium-dependent relaxation of the guinea pig pulmonary artery induced by histamine was inhibited by preincubation of the tissue with 10 microM N-ethylmaleimide (NEM) for 10 min, whereas the endothelium-dependent relaxation induced by the calcium ionophore A 23187 was not affected by NEM. Pretreatment of the preparations with 0.2-1 microgram/ml pertussis toxin for 120 min inhibited concentration-dependently the histamine-induced relaxation. In contrast, endothelium-dependent relaxation in response to the calcium ionophore A 23187 was not affected by pertussis toxin. Since NEM and pertussis toxin are thought to interfere with membrane located GTP binding proteins, it is suggested that such a coupling protein is involved in the signal transduction of the histamine receptor leading to endothelium-dependent relaxation.
Weinheimer
G
G
Gödecke Research Institute, Freiburg, Federal Republic of Germany.
Osswald
H
H
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000502:physiology*; D005033:Ethylmaleimide / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D006633:Histamine Antagonists; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D037342:Pertussis Toxin; D011651:Pulmonary Artery / Q000187:drug effects; D011969:Receptors, Histamine H1 / Q000378:metabolism; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D006633:Histamine Antagonists; D011969:Receptors, Histamine H1; D010566:Virulence Factors, Bordetella; D000001:Calcimycin; D037342:Pertussis Toxin; D005033:Ethylmaleimide; D009638:Norepinephrine