Natural polyamines stimulate G-proteins.
The natural polyamines spermine and spermidine, the biosynthetic precursor putrescine and their analogues cadaverine and tyramine stimulate the GTPase activity of purified GTP-binding proteins (Go/Gi) from calf brain reconstituted into phospholipid vesicles. The order of potency was spermine greater than spermidine greater than putrescine = cadaverine greater than tyramine. The physiological relevance of this observation was assessed, showing the same order of potency of polyamines in the stimulation of peritoneal and tracheal rat mast cells. The activation of rat mast cells by polyamines was inhibited by benzalkonium chloride or by a 2 h pretreatment of the cells with pertussis toxin. The increase in inositol phosphates evoked by polyamines was also inhibited by pertussis toxin. Therefore we propose that intracellular polyamines might control the basal level of second messengers and modulate extracellular signals transduced through G-protein-coupled receptors.
Bueb
J L
JL
Laboratoire de Neuroimmunopharmacologie, Université Louis Pasteur-Strasbourg I, Illkirch, France.
Da Silva
A
A
Mousli
M
M
Landry
Y
Y
D000818:Animals; D001548:Benzalkonium Compounds / Q000494:pharmacology; D001921:Brain / Q000378:metabolism; D002417:Cattle; D020558:GTP Phosphohydrolases / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006636:Histamine Release / Q000187:drug effects; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000096:biosynthesis; D008297:Male; D008407:Mast Cells / Q000378:metabolism; D009119:Muscle Contraction; D010529:Peritoneal Cavity / Q000166:cytology; D037342:Pertussis Toxin; D011073:Polyamines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D014132:Trachea / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D001548:Benzalkonium Compounds; D007295:Inositol Phosphates; D011073:Polyamines; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins