title: Differential inhibition and potentiation of chemoattractant-induced superoxide formation in human neutrophils by the cell-permeant analogue of cyclic GMP, N2,2'-O-dibutyryl guanosine 3':5'-cyclic monophosphate.
abstract: Human neutrophils possess a superoxide (O2-)-forming NADPH oxidase which is activated by the chemoattractants, N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMet-Leu-Phe), complement C5a, platelet-activating factor and leukotriene B4. We studied the roles of cAMP and cGMP in the regulation of O2- formation using the cell-permeant analogues of cyclic nucleotides, N6,2'-O-dibutyryl adenosine 3':5'-cyclic monophosphate (Bt2cAMP) and N2,2'-O-dibutyryl guanosine 3':5'-cyclic monophosphate (Bt2cGMP). Bt2cAMP inhibited O2- formation induced by these chemoattractants to similar extents. Bt2cGMP as low as 10 mumol/l significantly inhibited O2- formation induced by fMet-Leu-Phe at a submaximally effective concentration (50 nmol/l), and Bt2cGMP was more effective in diminishing O2- formation than Bt2cAMP. In contrast, Bt2cGMP did not affect O2- formation induced by fMet-Leu-Phe at a maximally effective concentration (1 mumol/l). Bt2cGMP (0.1 and 1 mmol/l) enhanced O2- formation induced by 0.1 mumol/1 C5a by 23% and 49%, respectively, and Bt2cGMP antagonized inhibition of O2- formation caused by Bt2cAMP. Bt2cGMP inhibited platelet-activating factor-induced O2- formation to a lesser extent than Bt2cAMP and had no effect on that induced by leukotriene B4. Bt2cAMP and Bt2cGMP had no effect on O2- formation induced by NAF, gamma-hexachlorocyclohexane, phorbol myristate acetate, A 23187 and arachidonic acid. Our data suggest that: 1. Bt2cAMP generally inhibits chemoattractant-stimulated O2- formation. 2. Bt2cGMP inhibits fMet-Leu-Phe- and platelet-activating factor-stimulated O2- formation but potentiates C5a-induced O2- formation.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Institut für Pharmakologie, Freie Universität Berlin, Federal Republic of Germany.
authors.forename: J
authors.initials: J
authors.lastname: Ervens
authors.forename: G
authors.initials: G
authors.lastname: Schultz
authors.forename: R
authors.initials: R
authors.lastname: Seifert
mesh_terms: D003994:Bucladesine / Q000494:pharmacology*; D000242:Cyclic AMP / Q000031:analogs & derivatives; D006152:Cyclic GMP / Q000031:analogs & derivatives; D003995:Dibutyryl Cyclic GMP / Q000494:pharmacology*; D006801:Humans; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D012724:Sex Attractants / Q000494:pharmacology*; D013481:Superoxides / Q000302:isolation & purification*
chemical_list: D012724:Sex Attractants; D013481:Superoxides; D003995:Dibutyryl Cyclic GMP; D003994:Bucladesine; D000242:Cyclic AMP; D006152:Cyclic GMP