Suppressing effect of pertussis toxin on clonidine-induced inhibition of noradrenaline release from cerebral cortical slices of rats.
Clonidine at 1.0 microM significantly decreased 20 mM K+-evoked release of L-[3H]noradrenaline (NA) from rat cerebral cortical slices preloaded with L-[3H]NA. Inhibitory effects of clonidine, however, were not observed in slices pretreated with 20 micrograms/ml pertussis toxin, an islet-activating protein, together with NAD and adenosine triphosphate. It is suggested that the inhibitory guanine nucleotide-binding protein (Ni) could be involved in alpha 2-adrenoceptor-mediated inhibition of NA release from nerve terminals in the central nervous system.
D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology*; D003000:Clonidine / Q000008:administration & dosage*; D004347:Drug Interactions; D019204:GTP-Binding Proteins / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D009638:Norepinephrine / Q000378:metabolism*; D037342:Pertussis Toxin; D011188:Potassium / Q000008:administration & dosage; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D010566:Virulence Factors, Bordetella / Q000008:administration & dosage*
D011942:Receptors, Adrenergic, alpha; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D003000:Clonidine; D011188:Potassium; D009638:Norepinephrine