Pertussis toxin attenuates presynaptic inhibition of cholinergic but not nonadrenergic noncholinergic contraction in guinea pig airways.
Several alpha-2- and opioid receptors exert their intracellular effects via a pertussis toxin-sensitive G protein. Both cholinergic and nonadrenergic noncholinergic nerve-mediated contractions of airways can be reduced by stimulation of presynaptic alpha-2- and opioid receptors. Using guinea pig trachea and bronchi, pretreated with pertussis toxin 100 micrograms/kg or 0.9% NaCl, we investigated whether these inhibitory effects on airway contractions, evoked by electrical field stimulation, are mediated via a pertussis toxin-sensitive G protein. The results indicate a difference between cholinergic and excitatory nonadrenergic non-cholinergic neurotransmission. Inhibition of cholinergic contraction via presynaptic alpha-2- and opioid receptors seems to be mediated via a pertussis toxin-sensitive G protein, whereas inhibition of nonadrenergic noncholinergic contraction is not affected by pertussis toxin.
Department of Pharmacology, Faculty of Health Sciences, University of Linköping, Sweden.
I G
IG
Johansson-Rydberg
N
N
Grundström
R G
RG
Andersson
D000818:Animals; D000068438:Brimonidine Tartrate; D001980:Bronchi / Q000294:innervation*; D004305:Dose-Response Relationship, Drug; D019204:GTP-Binding Proteins / Q000502:physiology*; D006168:Guinea Pigs; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D010275:Parasympathetic Nervous System / Q000187:drug effects* / Q000502:physiology; D037342:Pertussis Toxin; D011810:Quinoxalines / Q000494:pharmacology; D018341:Receptors, Adrenergic, alpha-2 / Q000502:physiology; D011957:Receptors, Opioid / Q000502:physiology; D014132:Trachea / Q000294:innervation*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D011810:Quinoxalines; D018341:Receptors, Adrenergic, alpha-2; D011957:Receptors, Opioid; D010566:Virulence Factors, Bordetella; D000068438:Brimonidine Tartrate; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins