Differential effect of pertussis toxin on the affinity state for agonists of renal alpha 1- and alpha 2- adrenoceptors.
The effect of pertussis toxin treatment on the guanine nucleotide-induced modulation of the affinity of renal alpha 1- and alpha 2-adrenergic receptors was investigated. Pretreatment of rats with pertussis toxin did not induce any change in the number of or affinity for antagonists of alpha 1- or alpha 2-receptors studied using [3H]prazosin and [3H]yohimbine, respectively. Guanyl-5'-yl imidodiphosphate induced an "up-shift" in the number of alpha 2-adrenergic receptors; this up-shift was not observed for alpha 1-adrenergic receptors. Pertussis toxin treatment decreased the affinity of epinephrine for the [3H]yohimbine-binding sites and reduced the ability of guanine nucleotides to modulate alpha 2-adrenoceptor agonist affinity. The regulation by guanine nucleotides of alpha 1-adrenoceptor affinity for agonists was not altered. These results suggest that the modulation of alpha 1- and alpha 2-adrenoceptors by guanine nucleotides is probably exerted through different molecular entities.
D000818:Animals; D001427:Bacterial Toxins / Q000494:pharmacology*; D002462:Cell Membrane / Q000378:metabolism; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D007672:Kidney Cortex / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D037342:Pertussis Toxin; D011224:Prazosin / Q000378:metabolism*; D011799:Quinazolines / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000378:metabolism*; D010566:Virulence Factors, Bordetella; D015016:Yohimbine / Q000378:metabolism*
D001427:Bacterial Toxins; D011799:Quinazolines; D011942:Receptors, Adrenergic, alpha; D010566:Virulence Factors, Bordetella; D015016:Yohimbine; D006165:Guanylyl Imidodiphosphate; D037342:Pertussis Toxin; D011224:Prazosin