title: Influence of pertussis toxin on the effects of guanine nucleotide on adenylate cyclase in rat striatal membranes.
abstract: The influence of pertussis toxin on the effects of guanine nucleotide on adenylate cyclase activity were investigated in rat striatal membranes. GTP promoted and inhibited the activity at 1 and 100 microM, respectively. The inhibitory effects of GTP were abolished by pretreatment of the membranes with pertussis toxin. GppNHp (guanyl-5'-y1-beta,gamma-imidodiphosphate) exerted only stimulatory effects and pertussis toxin did not affect the effects of GppNHp. GDP at 10 and 100 microM caused significant inhibition which was completely suppressed by pertussis toxin. It is suggested that guanine nucleotide regulates the affinity of as in stimulatory GTP-binding regulatory protein to either beta gamma or catalytic units of adenylate cyclase in a flip-flop manner. Inhibitory GTP-binding regulatory protein seems to play a regulatory role in inhibiting alpha s activity supplying the beta gamma heterodimer.
mesh_terms: D037361:Adenylate Cyclase Toxin; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D003342:Corpus Striatum / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism; D006150:Guanine Nucleotides / Q000494:pharmacology*; D046911:Macromolecular Substances; D037342:Pertussis Toxin; D051381:Rats; D011954:Receptors, Dopamine / Q000187:drug effects*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
chemical_list: D037361:Adenylate Cyclase Toxin; D006150:Guanine Nucleotides; D046911:Macromolecular Substances; D011954:Receptors, Dopamine; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases